summary of bullying thesis

• Write my thesis
• Thesis writers
• Buy thesis papers
• Bachelor thesis
• Master's thesis
• Thesis editing services
• Thesis proofreading services
• Buy a thesis online
• Write my dissertation
• Dissertation proposal help
• Pay for dissertation
• Custom dissertation
• Dissertation help online
• Buy dissertation online
• Cheap dissertation
• Dissertation editing services
• Write my research paper
• Buy research paper online
• Pay for research paper
• Research paper help
• Order research paper
• Custom research paper
• Cheap research paper
• Research papers for sale
• Thesis subjects
• How It Works

What Is a Good Thesis Statement About Bullying?

Unfortunately, bullying is still part of our society despite civilization and technology. But, that does not mean the issue cannot be addressed and fixed. It is the responsibility of parents, teachers, and institutions to find a way to reduce the blow of bullying in our society for everyone to be safe and happy. Are you concerned about bullying and want to be a part of the solution? One of the ways to do this is by writing an interesting essay that educates about bullying and its effects. As a part of the project, you will need a thesis statement for a bullying essay that stands out.

As much as you want to address the nasty effects of bullying, you also need to pass your exams. That is why you need to get a thesis about bullying that will impress your professor. Let us learn more here.

What’s a Bullying Thesis Statement?

• How to Write a Thesis Statement about Bullying?

What Is a Good Thesis Statement For Bullying?

Interesting examples on thesis statement for bullying research paper, straightforward thesis statement for bullying essay examples, exciting thesis statement on cyberbullying homework, our writing services guarantees good thesis statement.

A bullying thesis statement helps you address an issue about bullying. It needs to include the topic of the research paper you are writing about and the claim you have about the bullying topic. Your thesis statement determines whether your paper will stand out.

Which Of The Following Statements About Bullying Is True?

Most people are oblivious to cyberbullying and its effect. So you need first to understand what bullying is to develop a great thesis statement for bullying. Below are four statements that you can read to determine the truth about bullying.

• Bullying is a growing phase that children will grow out of.
• Bullying does not have to be physical; it can also be cyberbullying, verbal, and emotional.
• Bullying is not harmful.
• As children mature, they will learn positive behavior on their own.

What do you think is the correct answer? All the above statements are false except b. Bullying is not limited to the physical like fighting and hitting. Cyberbullying, verbal and emotional abuse are all bullying, and they all have devastating effects on the individual or group of people getting bullied.

How to Write a Thesis Statement About Bullying?

The thesis on bullying should be under the introduction. Most students prefer writing a statement when they complete their introduction. But the best way to write a thesis is by finishing your research.

Note that the thesis statement needs to be a summary of your research. You will have a better idea of what your essay is all about once you have completed your project. Ensure that the subject is exciting and as per your tutor’s instruction.

A good thesis statement on bullying needs to be a great impression so that it can hook your instructor or any other person who will read your thesis statement. It needs to be the hook to your essay and motivate the readers. The bullying essay thesis statement needs to be;

• An interpretation of the subject
• Precise, forceful, and confident
• It should challenge the readers

Bullying Thesis Statement Examples

If you have a hard time creating a thesis statement about bullying that will make your essay stand out, worry no more. Our team of experts has combined a list of thesis statements on cyberbullying you can use in your essay to impress your professors. Here we go!

You can make your essay research paper interesting by choosing the right thesis statement about bullying to use. In case you are not sure, here is a list you can choose from.

• Bullying and its effects on youth, and some possible solutions to the problem it causes.
• There are several ideas and concepts that most institutes have come up with to help stop bullying, but the challenge is the implementation of these policies.
• International progress can be hasted by the eradication of bully in and so government bodies should cultivate solutions to address the matter.
• Corporate bullying could push individuals into isolation, leading to depression and suicide.
• Bullying has been ignored for a long time, even though it has been a problem in the school system; people have only recently started discussing it.

A bullying thesis does not have to be complex. In fact, at times keeping the thesis statement on bullying essay simple could help capture the attention of your tutor and help improve your grade. Here is a look at the straightforward statements about bullying.

• The effects of physical bullying are depression, stress, withdrawal, physical, and emotional problems, which could destroy a child’s life.
• Parents and tutors should always be on the lookout for any bullying so they can fix the problem before it gets out of control.
• Most bullies have emotional or physical abuse, so they turn to bullies to help them feel in a position of power.
• Bullying could affect the mental health of the person being bullied, affecting their everyday life.
• Bullies have a hard time following the regulations, caring for other people, and having self-control.

Cyberbullying is often underestimated, and it makes people feel as though they are not good enough and do not deserve to live. Use these examples in your homework.

• School violence and cyberbullying attacks affect everyone who attends the school and compromise students’ safety.
• Cyberbullying is not new and can be used in many ways to bring individuals or a group down, yet not much is being done to address the issue.
• Proper measures should be implemented to help better predict communication during cyberbullying episodes.
• As technology advances, teens have become more prone to the internet’s dangers like cyberbullying.
• A look at the similarities and differences between bullying and cyberbullying and the best way to handle both situations.

Are you still wondering what’s a good thesis statement for bullying is? Reach out to our writing service today. We have skilled writers to help you get the best bullying thesis for a research paper. We can also write the research paper for you and ensure you attain the best grades. So get in touch with us today.

Leave a Reply Cancel reply

Preventing Bullying Through Science, Policy, and Practice (2016)

Chapter: 1 introduction, 1 introduction.

Bullying, long tolerated by many as a rite of passage into adulthood, is now recognized as a major and preventable public health problem, one that can have long-lasting consequences ( McDougall and Vaillancourt, 2015 ; Wolke and Lereya, 2015 ). Those consequences—for those who are bullied, for the perpetrators of bullying, and for witnesses who are present during a bullying event—include poor school performance, anxiety, depression, and future delinquent and aggressive behavior. Federal, state, and local governments have responded by adopting laws and implementing programs to prevent bullying and deal with its consequences. However, many of these responses have been undertaken with little attention to what is known about bullying and its effects. Even the definition of bullying varies among both researchers and lawmakers, though it generally includes physical and verbal behavior, behavior leading to social isolation, and behavior that uses digital communications technology (cyberbullying). This report adopts the term “bullying behavior,” which is frequently used in the research field, to cover all of these behaviors.

Bullying behavior is evident as early as preschool, although it peaks during the middle school years ( Currie et al., 2012 ; Vaillancourt et al., 2010 ). It can occur in diverse social settings, including classrooms, school gyms and cafeterias, on school buses, and online. Bullying behavior affects not only the children and youth who are bullied, who bully, and who are both bullied and bully others but also bystanders to bullying incidents. Given the myriad situations in which bullying can occur and the many people who may be involved, identifying effective prevention programs and policies is challenging, and it is unlikely that any one approach will be ap-

propriate in all situations. Commonly used bullying prevention approaches include policies regarding acceptable behavior in schools and behavioral interventions to promote positive cultural norms.

STUDY CHARGE

Recognizing that bullying behavior is a major public health problem that demands the concerted and coordinated time and attention of parents, educators and school administrators, health care providers, policy makers, families, and others concerned with the care of children, a group of federal agencies and private foundations asked the National Academies of Sciences, Engineering, and Medicine to undertake a study of what is known and what needs to be known to further the field of preventing bullying behavior. The Committee on the Biological and Psychosocial Effects of Peer Victimization:

Lessons for Bullying Prevention was created to carry out this task under the Academies’ Board on Children, Youth, and Families and the Committee on Law and Justice. The study received financial support from the Centers for Disease Control and Prevention (CDC), the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the Health Resources and Services Administration, the Highmark Foundation, the National Institute of Justice, the Robert Wood Johnson Foundation, Semi J. and Ruth W. Begun Foundation, and the Substance Abuse and Mental Health Services Administration. The full statement of task for the committee is presented in Box 1-1 .

Although the committee acknowledges the importance of this topic as it pertains to all children in the United States and in U.S. territories, this report focuses on the 50 states and the District of Columbia. Also, while the committee acknowledges that bullying behavior occurs in the school

environment for youth in foster care, in juvenile justice facilities, and in other residential treatment facilities, this report does not address bullying behavior in those environments because it is beyond the study charge.

CONTEXT FOR THE STUDY

This section of the report highlights relevant work in the field and, later in the chapter under “The Committee’s Approach,” presents the conceptual framework and corresponding definitions of terms that the committee has adopted.

Historical Context

Bullying behavior was first characterized in the scientific literature as part of the childhood experience more than 100 years ago in “Teasing and Bullying,” published in the Pedagogical Seminary ( Burk, 1897 ). The author described bullying behavior, attempted to delineate causes and cures for the tormenting of others, and called for additional research ( Koo, 2007 ). Nearly a century later, Dan Olweus, a Swedish research professor of psychology in Norway, conducted an intensive study on bullying ( Olweus, 1978 ). The efforts of Olweus brought awareness to the issue and motivated other professionals to conduct their own research, thereby expanding and contributing to knowledge of bullying behavior. Since Olweus’s early work, research on bullying has steadily increased (see Farrington and Ttofi, 2009 ; Hymel and Swearer, 2015 ).

Over the past few decades, venues where bullying behavior occurs have expanded with the advent of the Internet, chat rooms, instant messaging, social media, and other forms of digital electronic communication. These modes of communication have provided a new communal avenue for bullying. While the media reports linking bullying to suicide suggest a causal relationship, the available research suggests that there are often multiple factors that contribute to a youth’s suicide-related ideology and behavior. Several studies, however, have demonstrated an association between bullying involvement and suicide-related ideology and behavior (see, e.g., Holt et al., 2015 ; Kim and Leventhal, 2008 ; Sourander, 2010 ; van Geel et al., 2014 ).

In 2013, the Health Resources and Services Administration of the U.S. Department of Health and Human Services requested that the Institute of Medicine 1 and the National Research Council convene an ad hoc planning committee to plan and conduct a 2-day public workshop to highlight relevant information and knowledge that could inform a multidisciplinary

___________________

1 Prior to 2015, the National Academy of Medicine was known as the Institute of Medicine.

road map on next steps for the field of bullying prevention. Content areas that were explored during the April 2014 workshop included the identification of conceptual models and interventions that have proven effective in decreasing bullying and the antecedents to bullying while increasing protective factors that mitigate the negative health impact of bullying. The discussions highlighted the need for a better understanding of the effectiveness of program interventions in realistic settings; the importance of understanding what works for whom and under what circumstances, as well as the influence of different mediators (i.e., what accounts for associations between variables) and moderators (i.e., what affects the direction or strength of associations between variables) in bullying prevention efforts; and the need for coordination among agencies to prevent and respond to bullying. The workshop summary ( Institute of Medicine and National Research Council, 2014c ) informs this committee’s work.

Federal Efforts to Address Bullying and Related Topics

Currently, there is no comprehensive federal statute that explicitly prohibits bullying among children and adolescents, including cyberbullying. However, in the wake of the growing concerns surrounding the implications of bullying, several federal initiatives do address bullying among children and adolescents, and although some of them do not primarily focus on bullying, they permit some funds to be used for bullying prevention purposes.

The earliest federal initiative was in 1999, when three agencies collaborated to establish the Safe Schools/Healthy Students initiative in response to a series of deadly school shootings in the late 1990s. The program is administered by the U.S. Departments of Education, Health and Human Services, and Justice to prevent youth violence and promote the healthy development of youth. It is jointly funded by the Department of Education and by the Department of Health and Human Services’ Substance Abuse and Mental Health Services Administration. The program has provided grantees with both the opportunity to benefit from collaboration and the tools to sustain it through deliberate planning, more cost-effective service delivery, and a broader funding base ( Substance Abuse and Mental Health Services Administration, 2015 ).

The next major effort was in 2010, when the Department of Education awarded $38.8 million in grants under the Safe and Supportive Schools (S3) Program to 11 states to support statewide measurement of conditions for learning and targeted programmatic interventions to improve conditions for learning, in order to help schools improve safety and reduce substance use. The S3 Program was administered by the Safe and Supportive Schools Group, which also administered the Safe and Drug-Free Schools and Communities Act State and Local Grants Program, authorized by the

1994 Elementary and Secondary Education Act. 2 It was one of several programs related to developing and maintaining safe, disciplined, and drug-free schools. In addition to the S3 grants program, the group administered a number of interagency agreements with a focus on (but not limited to) bullying, school recovery research, data collection, and drug and violence prevention activities ( U.S. Department of Education, 2015 ).

A collaborative effort among the U.S. Departments of Agriculture, Defense, Education, Health and Human Services, Interior, and Justice; the Federal Trade Commission; and the White House Initiative on Asian Americans and Pacific Islanders created the Federal Partners in Bullying Prevention (FPBP) Steering Committee. Led by the U.S. Department of Education, the FPBP works to coordinate policy, research, and communications on bullying topics. The FPBP Website provides extensive resources on bullying behavior, including information on what bullying is, its risk factors, its warning signs, and its effects. 3 The FPBP Steering Committee also plans to provide details on how to get help for those who have been bullied. It also was involved in creating the “Be More than a Bystander” Public Service Announcement campaign with the Ad Council to engage students in bullying prevention. To improve school climate and reduce rates of bullying nationwide, FPBP has sponsored four bullying prevention summits attended by education practitioners, policy makers, researchers, and federal officials.

In 2014, the National Institute of Justice—the scientific research arm of the U.S. Department of Justice—launched the Comprehensive School Safety Initiative with a congressional appropriation of $75 million. The funds are to be used for rigorous research to produce practical knowledge that can improve the safety of schools and students, including bullying prevention. The initiative is carried out through partnerships among researchers, educators, and other stakeholders, including law enforcement, behavioral and mental health professionals, courts, and other justice system professionals ( National Institute of Justice, 2015 ).

In 2015, the Every Student Succeeds Act was signed by President Obama, reauthorizing the 50-year-old Elementary and Secondary Education Act, which is committed to providing equal opportunities for all students. Although bullying is neither defined nor prohibited in this act, it is explicitly mentioned in regard to applicability of safe school funding, which it had not been in previous iterations of the Elementary and Secondary Education Act.

The above are examples of federal initiatives aimed at promoting the

2 The Safe and Drug-Free Schools and Communities Act was included as Title IV, Part A, of the 1994 Elementary and Secondary Education Act. See http://www.ojjdp.gov/pubs/gun_violence/sect08-i.html [October 2015].

3 For details, see http://www.stopbullying.gov/ [October 2015].

healthy development of youth, improving the safety of schools and students, and reducing rates of bullying behavior. There are several other federal initiatives that address student bullying directly or allow funds to be used for bullying prevention activities.

Definitional Context

The terms “bullying,” “harassment,” and “peer victimization” have been used in the scientific literature to refer to behavior that is aggressive, is carried out repeatedly and over time, and occurs in an interpersonal relationship where a power imbalance exists ( Eisenberg and Aalsma, 2005 ). Although some of these terms have been used interchangeably in the literature, peer victimization is targeted aggressive behavior of one child against another that causes physical, emotional, social, or psychological harm. While conflict and bullying among siblings are important in their own right ( Tanrikulu and Campbell, 2015 ), this area falls outside of the scope of the committee’s charge. Sibling conflict and aggression falls under the broader concept of interpersonal aggression, which includes dating violence, sexual assault, and sibling violence, in addition to bullying as defined for this report. Olweus (1993) noted that bullying, unlike other forms of peer victimization where the children involved are equally matched, involves a power imbalance between the perpetrator and the target, where the target has difficulty defending him or herself and feels helpless against the aggressor. This power imbalance is typically considered a defining feature of bullying, which distinguishes this particular form of aggression from other forms, and is typically repeated in multiple bullying incidents involving the same individuals over time ( Olweus, 1993 ).

Bullying and violence are subcategories of aggressive behavior that overlap ( Olweus, 1996 ). There are situations in which violence is used in the context of bullying. However, not all forms of bullying (e.g., rumor spreading) involve violent behavior. The committee also acknowledges that perspective about intentions can matter and that in many situations, there may be at least two plausible perceptions involved in the bullying behavior.

A number of factors may influence one’s perception of the term “bullying” ( Smith and Monks, 2008 ). Children and adolescents’ understanding of the term “bullying” may be subject to cultural interpretations or translations of the term ( Hopkins et al., 2013 ). Studies have also shown that influences on children’s understanding of bullying include the child’s experiences as he or she matures and whether the child witnesses the bullying behavior of others ( Hellström et al., 2015 ; Monks and Smith, 2006 ; Smith and Monks, 2008 ).

In 2010, the FPBP Steering Committee convened its first summit, which brought together more than 150 nonprofit and corporate leaders,

researchers, practitioners, parents, and youths to identify challenges in bullying prevention. Discussions at the summit revealed inconsistencies in the definition of bullying behavior and the need to create a uniform definition of bullying. Subsequently, a review of the 2011 CDC publication of assessment tools used to measure bullying among youth ( Hamburger et al., 2011 ) revealed inconsistent definitions of bullying and diverse measurement strategies. Those inconsistencies and diverse measurements make it difficult to compare the prevalence of bullying across studies ( Vivolo et al., 2011 ) and complicate the task of distinguishing bullying from other types of aggression between youths. A uniform definition can support the consistent tracking of bullying behavior over time, facilitate the comparison of bullying prevalence rates and associated risk and protective factors across different data collection systems, and enable the collection of comparable information on the performance of bullying intervention and prevention programs across contexts ( Gladden et al., 2014 ). The CDC and U.S. Department of Education collaborated on the creation of the following uniform definition of bullying (quoted in Gladden et al., 2014, p. 7 ):

Bullying is any unwanted aggressive behavior(s) by another youth or group of youths who are not siblings or current dating partners that involves an observed or perceived power imbalance and is repeated multiple times or is highly likely to be repeated. Bullying may inflict harm or distress on the targeted youth including physical, psychological, social, or educational harm.

This report noted that the definition includes school-age individuals ages 5-18 and explicitly excludes sibling violence and violence that occurs in the context of a dating or intimate relationship ( Gladden et al., 2014 ). This definition also highlighted that there are direct and indirect modes of bullying, as well as different types of bullying. Direct bullying involves “aggressive behavior(s) that occur in the presence of the targeted youth”; indirect bullying includes “aggressive behavior(s) that are not directly communicated to the targeted youth” ( Gladden et al., 2014, p. 7 ). The direct forms of violence (e.g., sibling violence, teen dating violence, intimate partner violence) can include aggression that is physical, sexual, or psychological, but the context and uniquely dynamic nature of the relationship between the target and the perpetrator in which these acts occur is different from that of peer bullying. Examples of direct bullying include pushing, hitting, verbal taunting, or direct written communication. A common form of indirect bullying is spreading rumors. Four different types of bullying are commonly identified—physical, verbal, relational, and damage to property. Some observational studies have shown that the different forms of bullying that youths commonly experience may overlap ( Bradshaw et al., 2015 ;

Godleski et al., 2015 ). The four types of bullying are defined as follows ( Gladden et al., 2014 ):

• Physical bullying involves the use of physical force (e.g., shoving, hitting, spitting, pushing, and tripping).
• Verbal bullying involves oral or written communication that causes harm (e.g., taunting, name calling, offensive notes or hand gestures, verbal threats).
• Relational bullying is behavior “designed to harm the reputation and relationships of the targeted youth (e.g., social isolation, rumor spreading, posting derogatory comments or pictures online).”
• Damage to property is “theft, alteration, or damaging of the target youth’s property by the perpetrator to cause harm.”

In recent years, a new form of aggression or bullying has emerged, labeled “cyberbullying,” in which the aggression occurs through modern technological devices, specifically mobile phones or the Internet ( Slonje and Smith, 2008 ). Cyberbullying may take the form of mean or nasty messages or comments, rumor spreading through posts or creation of groups, and exclusion by groups of peers online.

While the CDC definition identifies bullying that occurs using technology as electronic bullying and views that as a context or location where bullying occurs, one of the major challenges in the field is how to conceptualize and define cyberbullying ( Tokunaga, 2010 ). The extent to which the CDC definition can be applied to cyberbullying is unclear, particularly with respect to several key concepts within the CDC definition. First, whether determination of an interaction as “wanted” or “unwanted” or whether communication was intended to be harmful can be challenging to assess in the absence of important in-person socioemotional cues (e.g., vocal tone, facial expressions). Second, assessing “repetition” is challenging in that a single harmful act on the Internet has the potential to be shared or viewed multiple times ( Sticca and Perren, 2013 ). Third, cyberbullying can involve a less powerful peer using technological tools to bully a peer who is perceived to have more power. In this manner, technology may provide the tools that create a power imbalance, in contrast to traditional bullying, which typically involves an existing power imbalance.

A study that used focus groups with college students to discuss whether the CDC definition applied to cyberbullying found that students were wary of applying the definition due to their perception that cyberbullying often involves less emphasis on aggression, intention, and repetition than other forms of bullying ( Kota et al., 2014 ). Many researchers have responded to this lack of conceptual and definitional clarity by creating their own measures to assess cyberbullying. It is noteworthy that very few of these

definitions and measures include the components of traditional bullying—i.e., repetition, power imbalance, and intent ( Berne et al., 2013 ). A more recent study argues that the term “cyberbullying” should be reserved for incidents that involve key aspects of bullying such as repetition and differential power ( Ybarra et al., 2014 ).

Although the formulation of a uniform definition of bullying appears to be a step in the right direction for the field of bullying prevention, there are some limitations of the CDC definition. For example, some researchers find the focus on school-age youth as well as the repeated nature of bullying to be rather limiting; similarly the exclusion of bullying in the context of sibling relationships or dating relationships may preclude full appreciation of the range of aggressive behaviors that may co-occur with or constitute bullying behavior. As noted above, other researchers have raised concerns about whether cyberbullying should be considered a particular form or mode under the broader heading of bullying as suggested in the CDC definition, or whether a separate defintion is needed. Furthermore, the measurement of bullying prevalence using such a definiton of bullying is rather complex and does not lend itself well to large-scale survey research. The CDC definition was intended to inform public health surveillance efforts, rather than to serve as a definition for policy. However, increased alignment between bullying definitions used by policy makers and researchers would greatly advance the field. Much of the extant research on bullying has not applied a consistent definition or one that aligns with the CDC definition. As a result of these and other challenges to the CDC definition, thus far there has been inconsistent adoption of this particular definition by researchers, practitioners, or policy makers; however, as the definition was created in 2014, less than 2 years is not a sufficient amount of time to assess whether it has been successfully adopted or will be in the future.

THE COMMITTEE’S APPROACH

This report builds on the April 2014 workshop, summarized in Building Capacity to Reduce Bullying: Workshop Summary ( Institute of Medicine and National Research Council, 2014c ). The committee’s work was accomplished over an 18-month period that began in October 2014, after the workshop was held and the formal summary of it had been released. The study committee members represented expertise in communication technology, criminology, developmental and clinical psychology, education, mental health, neurobiological development, pediatrics, public health, school administration, school district policy, and state law and policy. (See Appendix E for biographical sketches of the committee members and staff.) The committee met three times in person and conducted other meetings by teleconferences and electronic communication.

Information Gathering

The committee conducted an extensive review of the literature pertaining to peer victimization and bullying. In some instances, the committee drew upon the broader literature on aggression and violence. The review began with an English-language literature search of online databases, including ERIC, Google Scholar, Lexis Law Reviews Database, Medline, PubMed, Scopus, PsycInfo, and Web of Science, and was expanded as literature and resources from other countries were identified by committee members and project staff as relevant. The committee drew upon the early childhood literature since there is substantial evidence indicating that bullying involvement happens as early as preschool (see Vlachou et al., 2011 ). The committee also drew on the literature on late adolescence and looked at related areas of research such as maltreatment for insights into this emerging field.

The committee used a variety of sources to supplement its review of the literature. The committee held two public information-gathering sessions, one with the study sponsors and the second with experts on the neurobiology of bullying; bullying as a group phenomenon and the role of bystanders; the role of media in bullying prevention; and the intersection of social science, the law, and bullying and peer victimization. See Appendix A for the agendas for these two sessions. To explore different facets of bullying and give perspectives from the field, a subgroup of the committee and study staff also conducted a site visit to a northeastern city, where they convened four stakeholder groups comprised, respectively, of local practitioners, school personnel, private foundation representatives, and young adults. The site visit provided the committee with an opportunity for place-based learning about bullying prevention programs and best practices. Each focus group was transcribed and summarized thematically in accordance with this report’s chapter considerations. Themes related to the chapters are displayed throughout the report in boxes titled “Perspectives from the Field”; these boxes reflect responses synthesized from all four focus groups. See Appendix B for the site visit’s agenda and for summaries of the focus groups.

The committee also benefited from earlier reports by the National Academies of Sciences, Engineering, and Medicine through its Division of Behavioral and Social Sciences and Education and the Institute of Medicine, most notably:

• Reducing Risks for Mental Disorders: Frontiers for Preventive Intervention Research ( Institute of Medicine, 1994 )
• Community Programs to Promote Youth Development ( National Research Council and Institute of Medicine, 2002 )
• Deadly Lessons: Understanding Lethal School Violence ( National Research Council and Institute of Medicine, 2003 )
• Preventing Mental, Emotional, and Behavioral Disorders Among Young People: Progress and Possibilities ( National Research Council and Institute of Medicine, 2009 )
• The Science of Adolescent Risk-Taking: Workshop Report ( Institute of Medicine and National Research Council, 2011 )
• Communications and Technology for Violence Prevention: Workshop Summary ( Institute of Medicine and National Research Council, 2012 )
• Building Capacity to Reduce Bullying: Workshop Summary ( Institute of Medicine and National Research Council, 2014c )
• The Evidence for Violence Prevention across the Lifespan and Around the World: Workshop Summary ( Institute of Medicine and National Research Council, 2014a )
• Strategies for Scaling Effective Family-Focused Preventive Interventions to Promote Children’s Cognitive, Affective, and Behavioral Health: Workshop Summary ( Institute of Medicine and National Research Council, 2014b )
• Investing in the Health and Well-Being of Young Adults ( Institute of Medicine and National Research Council, 2015 )

Although these past reports and workshop summaries address various forms of violence and victimization, this report is the first consensus study by the National Academies of Sciences, Engineering, and Medicine on the state of the science on the biological and psychosocial consequences of bullying and the risk and protective factors that either increase or decrease bullying behavior and its consequences.

Terminology

Given the variable use of the terms “bullying” and “peer victimization” in both the research-based and practice-based literature, the committee chose to use the current CDC definition quoted above ( Gladden et al., 2014, p. 7 ). While the committee determined that this was the best definition to use, it acknowledges that this definition is not necessarily the most user-friendly definition for students and has the potential to cause problems for students reporting bullying. Not only does this definition provide detail on the common elements of bullying behavior but it also was developed with input from a panel of researchers and practitioners. The committee also followed the CDC in focusing primarily on individuals between the ages of 5 and 18. The committee recognizes that children’s development occurs on a continuum, and so while it relied primarily on the CDC defini-

tion, its work and this report acknowledge the importance of addressing bullying in both early childhood and emerging adulthood. For purposes of this report, the committee used the terms “early childhood” to refer to ages 1-4, “middle childhood” for ages 5 to 10, “early adolescence” for ages 11-14, “middle adolescence” for ages 15-17, and “late adolescence” for ages 18-21. This terminology and the associated age ranges are consistent with the Bright Futures and American Academy of Pediatrics definition of the stages of development. 4

A given instance of bullying behavior involves at least two unequal roles: one or more individuals who perpetrate the behavior (the perpetrator in this instance) and at least one individual who is bullied (the target in this instance). To avoid labeling and potentially further stigmatizing individuals with the terms “bully” and “victim,” which are sometimes viewed as traits of persons rather than role descriptions in a particular instance of behavior, the committee decided to use “individual who is bullied” to refer to the target of a bullying instance or pattern and “individual who bullies” to refer to the perpetrator of a bullying instance or pattern. Thus, “individual who is bullied and bullies others” can refer to one who is either perpetrating a bullying behavior or a target of bullying behavior, depending on the incident. This terminology is consistent with the approach used by the FPBP (see above). Also, bullying is a dynamic social interaction ( Espelage and Swearer, 2003 ) where individuals can play different roles in bullying interactions based on both individual and contextual factors.

The committee used “cyberbullying” to refer to bullying that takes place using technology or digital electronic means. “Digital electronic forms of contact” comprise a broad category that may include e-mail, blogs, social networking Websites, online games, chat rooms, forums, instant messaging, Skype, text messaging, and mobile phone pictures. The committee uses the term “traditional bullying” to refer to bullying behavior that is not cyberbullying (to aid in comparisons), recognizing that the term has been used at times in slightly different senses in the literature.

Where accurate reporting of study findings requires use of the above terms but with senses different from those specified here, the committee has noted the sense in which the source used the term. Similarly, accurate reporting has at times required use of terms such as “victimization” or “victim” that the committee has chosen to avoid in its own statements.

4 For details on these stages of adolescence, see https://brightfutures.aap.org/Bright%20Futures%20Documents/3-Promoting_Child_Development.pdf [October 2015].

ORGANIZATION OF THE REPORT

This report is organized into seven chapters. After this introductory chapter, Chapter 2 provides a broad overview of the scope of the problem.

Chapter 3 focuses on the conceptual frameworks for the study and the developmental trajectory of the child who is bullied, the child who bullies, and the child who is bullied and also bullies. It explores processes that can explain heterogeneity in bullying outcomes by focusing on contextual processes that moderate the effect of individual characteristics on bullying behavior.

Chapter 4 discusses the cyclical nature of bullying and the consequences of bullying behavior. It summarizes what is known about the psychosocial, physical health, neurobiological, academic-performance, and population-level consequences of bullying.

Chapter 5 provides an overview of the landscape in bullying prevention programming. This chapter describes in detail the context for preventive interventions and the specific actions that various stakeholders can take to achieve a coordinated response to bullying behavior. The chapter uses the Institute of Medicine’s multi-tiered framework ( National Research Council and Institute of Medicine, 2009 ) to present the different levels of approaches to preventing bullying behavior.

Chapter 6 reviews what is known about federal, state, and local laws and policies and their impact on bullying.

After a critical review of the relevant research and practice-based literatures, Chapter 7 discusses the committee conclusions and recommendations and provides a path forward for bullying prevention.

The report includes a number of appendixes. Appendix A includes meeting agendas of the committee’s public information-gathering meetings. Appendix B includes the agenda and summaries of the site visit. Appendix C includes summaries of bullying prevalence data from the national surveys discussed in Chapter 2 . Appendix D provides a list of selected federal resources on bullying for parents and teachers. Appendix E provides biographical sketches of the committee members and project staff.

Berne, S., Frisén, A., Schultze-Krumbholz, A., Scheithauer, H., Naruskov, K., Luik, P., Katzer, C., Erentaite, R., and Zukauskiene, R. (2013). Cyberbullying assessment instruments: A systematic review. Aggression and Violent Behavior, 18 (2), 320-334.

Bradshaw, C.P., Waasdorp, T.E., and Johnson, S.L. (2015). Overlapping verbal, relational, physical, and electronic forms of bullying in adolescence: Influence of school context. Journal of Clinical Child & Adolescent Psychology, 44 (3), 494-508.

Burk, F.L. (1897). Teasing and bullying. The Pedagogical Seminary, 4 (3), 336-371.

Currie, C., Zanotti, C., Morgan, A., Currie, D., de Looze, M., Roberts, C., Samdal, O., Smith, O.R., and Barnekow, V. (2012). Social determinants of health and well-being among young people. Copenhagen, Denmark: World Health Organization Regional Office for Europe.

Eisenberg, M.E., and Aalsma, M.C. (2005). Bullying and peer victimization: Position paper of the Society for Adolescent Medicine. Journal of Adolescent Health, 36 (1), 88-91.

Espelage, D.L., and Swearer, S.M. (2003). Research on school bullying and victimization: What have we learned and where do we go from here? School Psychology Review, 32 (3), 365-383.

Farrington, D., and Ttofi, M. (2009). School-based programs to reduce bullying and victimization: A systematic review. Campbell Systematic Reviews, 5 (6).

Finkelhor, D., Ormrod, R.K., and Turner, H.A. (2007). Poly-victimization: A neglected component in child victimization. Child Abuse & Neglect , 31 (1), 7-26.

Gladden, R.M., Vivolo-Kantor, A.M., Hamburger, M.E., and Lumpkin, C.D. (2014). Bullying Surveillance among Youths: Uniform Definitions for Public Health and Recommended Data Elements, Version 1.0 . Atlanta, GA: Centers for Disease Control and Prevention and U.S. Department of Education.

Godleski, S.A., Kamper, K.E., Ostrov, J.M., Hart, E.J., and Blakely-McClure, S.J. (2015). Peer victimization and peer rejection during early childhood. Journal of Clinical Child & Adolescent Psychology, 44 (3), 380-392.

Hamburger, M.E., Basile, K.C., and Vivolo, A.M. (2011). Measuring Bullying Victimization, Perpetration, and Bystander Experiences: A Compendium of Assessment Tools. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Injury Prevention and Control.

Hellström, L., Persson, L., and Hagquist, C. (2015). Understanding and defining bullying—Adolescents’ own views. Archives of Public Health, 73 (4), 1-9.

Holt, M.K., Vivolo-Kantor, A.M., Polanin, J.R., Holland, K.M., DeGue, S., Matjasko, J.L., Wolfe, M., and Reid, G. (2015). Bullying and suicidal ideation and behaviors: A meta-analysis. Pediatrics, 135 (2), e496-e509.

Hopkins, L., Taylor, L., Bowen, E., and Wood, C. (2013). A qualitative study investigating adolescents’ understanding of aggression, bullying and violence. Children and Youth Services Review, 35 (4), 685-693.

Hymel, S., and Swearer, S.M. (2015). Four decades of research on school bullying: An introduction. American Psychologist, 70 (4), 293.

Institute of Medicine. (1994). Reducing Risks for Mental Disorders: Frontiers for Preventive Intervention Research. Committee on Prevention of Mental Disorders. P.J. Mrazek and R.J. Haggerty, Editors. Division of Biobehavioral Sciences and Mental Disorders. Washington, DC: National Academy Press.

Institute of Medicine and National Research Council. (2011). The Science of Adolescent Risk-taking: Workshop Report . Committee on the Science of Adolescence. Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2012). Communications and Technology for Violence Prevention: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2014a). The Evidence for Violence Prevention across the Lifespan and around the World: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2014b). Strategies for Scaling Effective Family-Focused Preventive Interventions to Promote Children’s Cognitive, Affective, and Behavioral Health: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2014c). Building Capacity to Reduce Bullying: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2015). Investing in the Health and Well-Being of Young Adults . Washington, DC: The National Academies Press.

Kim, Y.S., and Leventhal, B. (2008). Bullying and suicide. A review. International Journal of Adolescent Medicine and Health, 20 (2), 133-154.

Koo, H. (2007). A time line of the evolution of school bullying in differing social contexts. Asia Pacific Education Review, 8 (1), 107-116.

Kota, R., Schoohs, S., Benson, M., and Moreno, M.A. (2014). Characterizing cyberbullying among college students: Hacking, dirty laundry, and mocking. Societies, 4 (4), 549-560.

McDougall, P., and Vaillancourt, T. (2015). Long-term adult outcomes of peer victimization in childhood and adolescence: Pathways to adjustment and maladjustment. American Psychologist, 70 (4), 300.

Monks, C.P., and Smith, P.K. (2006). Definitions of bullying: Age differences in understanding of the term and the role of experience. British Journal of Developmental Psychology, 24 (4), 801-821.

National Institute of Justice. (2015). Comprehensive School Safety Initiative. 2015. Available: http://nij.gov/topics/crime/school-crime/Pages/school-safety-initiative.aspx#about [October 2015].

National Research Council and Institute of Medicine. (2002). Community Programs to Promote Youth Development . Committee on Community-Level Programs for Youth. J. Eccles and J.A. Gootman, Editors. Board on Children, Youth, and Families, Division of Behavioral and Social Sciences and Education. Washington, DC: National Academy Press.

National Research Council and Institute of Medicine. (2003). Deadly Lessons: Understanding Lethal School Violence . Case Studies of School Violence Committee. M.H. Moore, C.V. Petrie, A.A. Barga, and B.L. McLaughlin, Editors. Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press.

National Research Council and Institute of Medicine. (2009). Preventing Mental, Emotional, and Behavioral Disorders among Young People: Progress and Possibilities. Committee on the Prevention of Mental Disorders and Substance Abuse Among Children, Youth, and Young Adults: Research Advances and Promising Interventions. M.E. O’Connell, T. Boat, and K.E. Warner, Editors. Board on Children, Youth, and Families, Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press.

Olweus, D. (1978). Aggression in the Schools: Bullies and Whipping Boys. Washington, DC: Hemisphere.

Olweus, D. (1993). Bullying at School. What We Know and Whal We Can Do. Oxford, UK: Blackwell.

Olweus, D. (1996). Bully/victim problems in school. Prospects, 26 (2), 331-359.

Slonje, R., and Smith, P.K. (2008). Cyberbullying: Another main type of bullying? Scandinavian Journal of Psychology, 49 (2), 147-154.

Smith, P. ., and Monks, C. . (2008). Concepts of bullying: Developmental and cultural aspects. International Journal of Adolescent Medicine and Health, 20 (2), 101-112.

Sourander, A. (2010). The association of suicide and bullying in childhood to young adulthood: A review of cross-sectional and longitudinal research findings. Canadian Journal of Psychiatry, 55 (5), 282.

Sticca, F., and Perren, S. (2013). Is cyberbullying worse than traditional bullying? Examining the differential roles of medium, publicity, and anonymity for the perceived severity of bullying. Journal of Youth and Adolescence, 42 (5), 739-750.

Substance Abuse and Mental Health Services Administration. (2015). Safe Schools/Healthy Students. 2015. Available: http://www.samhsa.gov/safe-schools-healthy-students/about [November 2015].

Tanrikulu, I., and Campbell, M. (2015). Correlates of traditional bullying and cyberbullying perpetration among Australian students. Children and Youth Services Review , 55 , 138-146.

Tokunaga, R.S. (2010). Following you home from school: A critical review and synthesis of research on cyberbullying victimization. Computers in Human Behavior, 26 (3), 277-287.

U.S. Department of Education. (2015). Safe and Supportive Schools . Available: http://www.ed.gov/news/press-releases/us-department-education-awards-388-million-safe-and-supportive-school-grants [October 2015].

Vaillancourt, T., Trinh, V., McDougall, P., Duku, E., Cunningham, L., Cunningham, C., Hymel, S., and Short, K. (2010). Optimizing population screening of bullying in school-aged children. Journal of School Violence, 9 (3), 233-250.

van Geel, M., Vedder, P., and Tanilon, J. (2014). Relationship between peer victimization, cyberbullying, and suicide in children and adolescents: A meta-analysis. Journal of the American Medical Association. Pediatrics, 168 (5), 435-442.

Vivolo, A.M., Holt, M.K., and Massetti, G.M. (2011). Individual and contextual factors for bullying and peer victimization: Implications for prevention. Journal of School Violence, 10 (2), 201-212.

Vlachou, M., Andreou, E., Botsoglou, K., and Didaskalou, E. (2011). Bully/victim problems among preschool children: A review of current research evidence. Educational Psychology Review, 23 (3), 329-358.

Wolke, D., and Lereya, S.T. (2015). Long-term effects of bullying. Archives of Disease in Childhood, 100 (9), 879-885.

Ybarra, M.L., Espelage, D.L., and Mitchell, K.J. (2014). Differentiating youth who are bullied from other victims of peer-aggression: The importance of differential power and repetition. Journal of Adolescent Health, 55 (2), 293-300.

This page intentionally left blank.

Bullying has long been tolerated as a rite of passage among children and adolescents. There is an implication that individuals who are bullied must have "asked for" this type of treatment, or deserved it. Sometimes, even the child who is bullied begins to internalize this idea. For many years, there has been a general acceptance and collective shrug when it comes to a child or adolescent with greater social capital or power pushing around a child perceived as subordinate. But bullying is not developmentally appropriate; it should not be considered a normal part of the typical social grouping that occurs throughout a child's life.

Although bullying behavior endures through generations, the milieu is changing. Historically, bulling has occurred at school, the physical setting in which most of childhood is centered and the primary source for peer group formation. In recent years, however, the physical setting is not the only place bullying is occurring. Technology allows for an entirely new type of digital electronic aggression, cyberbullying, which takes place through chat rooms, instant messaging, social media, and other forms of digital electronic communication.

Composition of peer groups, shifting demographics, changing societal norms, and modern technology are contextual factors that must be considered to understand and effectively react to bullying in the United States. Youth are embedded in multiple contexts and each of these contexts interacts with individual characteristics of youth in ways that either exacerbate or attenuate the association between these individual characteristics and bullying perpetration or victimization. Recognizing that bullying behavior is a major public health problem that demands the concerted and coordinated time and attention of parents, educators and school administrators, health care providers, policy makers, families, and others concerned with the care of children, this report evaluates the state of the science on biological and psychosocial consequences of peer victimization and the risk and protective factors that either increase or decrease peer victimization behavior and consequences.

READ FREE ONLINE

Welcome to OpenBook!

You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

Do you want to take a quick tour of the OpenBook's features?

Show this book's table of contents , where you can jump to any chapter by name.

...or use these buttons to go back to the previous chapter or skip to the next one.

Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

Switch between the Original Pages , where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

To search the entire text of this book, type in your search term here and press Enter .

Share a link to this book page on your preferred social network or via email.

View our suggested citation for this chapter.

Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

Get Email Updates

Do you enjoy reading reports from the Academies online for free ? Sign up for email notifications and we'll let you know about new publications in your areas of interest when they're released.

An official website of the United States government

The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• Browse Titles

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Committee on the Biological and Psychosocial Effects of Peer Victimization: Lessons for Bullying Prevention; Board on Children, Youth, and Families; Committee on Law and Justice; Division of Behavioral and Social Sciences and Education; Health and Medicine Division; National Academies of Sciences, Engineering, and Medicine; Rivara F, Le Menestrel S, editors. Preventing Bullying Through Science, Policy, and Practice. Washington (DC): National Academies Press (US); 2016 Sep 14.

Preventing Bullying Through Science, Policy, and Practice.

• Hardcopy Version at National Academies Press

4 Consequences of Bullying Behavior

Bullying behavior is a serious problem among school-age children and adolescents; it has short- and long-term effects on the individual who is bullied, the individual who bullies, the individual who is bullied and bullies others, and the bystander present during the bullying event. In this chapter, the committee presents the consequences of bullying behavior for children and youth. As referenced in Chapter 1 , bullying can be either direct or indirect, and children and youth may experience different types of bullying. Specifically the committee examines physical (including neurobiological), mental, and behavioral health consequences. The committee also examines consequences for academic performance and achievement and explores evidence for some of the mechanisms proposed for the psychological effects of bullying. When applicable, we note the limited, correlational nature of much of the available research on the consequences of bullying.

• CONSEQUENCES FOR INDIVIDUALS WHO ARE BULLIED

Mounting evidence on bullying has highlighted the detrimental effects of being bullied on children's health and behavior ( Gini and Pozzoli, 2009 ; Lereya et al., 2015 ; Reijntjes et al., 2010 ; Ttofi et al., 2011 ). In this section, the committee reviews the research on physical, psychosocial, and academic achievement consequences for those children and youth who are bullied.

Perspectives from the Field

Being bullied makes young people incredibly insecure: When you're being bullied, you can feel constantly insecure and on guard. Even if you're not actively being bullied, you're aware it could start anytime. It has a big mental and emotional impact—you feel unaccepted, isolated, angry, and withdrawn. You're always wondering how you can do better and how you can escape a bully's notice. You're also stunted because of the constant tension and because maybe you forego making certain friendships or miss out on taking certain chances that could actually help your development.

—Summary of themes from young adults focus group (See Appendix B for additional highlights from interviews.)

Physical Health Consequences

The physical health consequences of bullying can be immediate, such as physical injury, or they can involve long-term effects, such as headaches, sleep disturbances, or somatization. 1 However, the long-term physical consequences of bullying can be difficult to identify and link with past bullying behavior versus being the result of other causes such as anxiety or other adverse childhood events that can also have physical effects into adulthood ( Hager and Leadbeater, 2016 ). In one of the few longitudinal studies on the physical and mental effects of bullying, Bogart and colleagues (2014) studied 4,297 children and their parents from three urban locales: Birmingham, Alabama; 25 contiguous school districts in Los Angeles County, California; and one of the largest school districts in Houston, Texas. Bogart and her team were interested in the cumulative effects of bullying on an individual. They collected data when the cohort was in fifth grade (2004 to 2006), seventh grade (2006 to 2008), and tenth grade (2008 to 2010). Data consisted of responses to the Peer Experience Questionnaire, the Pediatric Quality of Life Inventory with its Psychosocial Subscale and Physical Health Subscale, and a Self-Perception Profile. The Physical Health Subscale measured perceptions of physical quality of life.

Bogart and colleagues (2014) found that children who were bullied experienced negative physical health compared to non-involved peers. Among seventh grade students with the worst-decile physical health, 6.4 percent were not bullied, 14.8 percent had been bullied in the past only, 23.9 percent had been bullied in the present only, and nearly a third (30.2%) had been bullied in both the past and present. These effects were not as strong when students were in tenth grade. Limitations to this study were that physical health was measured by participants' perceptions of their health-related quality of life, rather than by objectively defined physical symptoms. It is critical to understand that this study, or other studies assessing correlations between behavior and events, cannot state that the events caused the behavior. Future research might build on this large multisite longitudinal study and obtain more in-depth evidence on individuals' physical health as a consequence of bullying.

In their study of 2,232 twins reared together and separately as a part of the Environmental Risk (E-Risk) Longitudinal Twin Study, Baldwin and colleagues (2015) found that children who had experienced chronic bullying showed greater adiposity subsequently, but not at the time of victimization. The study revealed that at age 18, these children had a higher body mass index ( b = 1.11, CI [0.33, 1.88]), waist-hip ratio ( b = 0.017, CI [0.008, 0.026]), and were at a higher risk of being overweight ( OR = 1.80, CI [1.28, 2.53]) than their nonbullied counterparts ( Baldwin et al., 2015 ).

An important future direction for research is to gather more information on physical consequences such as elevated blood pressure, inflammatory markers, and obesity in light of work showing effects on these outcome of harsh language by parents and other types of early life adversity ( Danese and Tan, 2014 ; Danese et al., 2007 ; Evans et al., 2007 ; Miller and Chen, 2010 ).

Somatic Symptoms

Most of the extant evidence on the physical consequences—somatic symptoms in particular—of bullying pertains to the individual who is bullied. The emotional effects of being bullied can be expressed through somatic disturbances, which, similar to somatization, are physical symptoms that originate from stress or an emotional condition. Common stress or anxiety-related symptoms include sleep disorders, gastrointestinal concerns, headaches, palpitations, and chronic pain. The relationship between peer victimization and sleep disturbances has been well documented ( Hunter et al., 2014 ; van Geel et al., 2014 ).

For instance, Hunter and colleagues (2014) examined sleep difficulties (feeling too tired to do things, had trouble getting to sleep, and had trouble staying asleep) among a sample of 5,420 Scottish adolescents. The researchers found that youth who were bullied ( OR = 1.72, 95% CI [1.07, 2.75]) and youth who bully ( OR = 1.80, CI [1.16, 2.81]) were nearly twice as likely as youth who were not involved in bullying to experience sleep difficulties. One limitation of this study is that it was based on self-reports, which have sometimes been criticized as being subject to specific biases. Patients with insomnia may overestimate how long it takes them to fall asleep ( Harvey and Tang, 2012 ). Another limitation is that the study included young people at different stages of adolescence. Sleep patterns and sleep requirements vary across the different stages of adolescence.

A recent meta-analysis based on 21 studies involving an international sample of 363,539 children and adolescents examined the association between peer victimization and sleeping problems. A broader focus on peer victimization was used because of the definitional issues related to bullying. The authors defined peer victimization as “being the victim of relational, verbal or physical aggression by peers” ( van Geel et al., 2015 , p. 89). Children and youth who were victimized reported more sleeping problems than children who did not report victimization ( OR = 2.21, 95% CI [2.01, 2.44]). Moreover, the relationship between peer victimization and sleeping problems was stronger for younger children than it was for older children ( van Geel et al., 2015 ). This study was based on cross-sectional studies that varied widely in how peer victimization and sleeping problems were operationalized and thus cannot make any claims about causal relations between peer victimization and sleeping problems.

Knack and colleagues (2011a) posited that bullying results in meaningful biological alterations that may result in changes in one's sensitivity to pain responses. A recent meta-analysis by Gini and Pozzoli (2013) concluded that children and adolescents who are bullied were at least twice as likely to have psychosomatic disturbances (headache, stomachache, dizziness, bedwetting, etc.) than nonbullied children and adolescents ( OR = 2.39, 95% CI [1.76, 3.24] for longitudinal studies; OR = 2.17, 95% CI [1.91, 2.46] for cross-sectional studies). Although the use of self-report measures are very common in bullying research and are usually considered to be valid and reliable (Ladd and Kochenderfer- Ladd, 2002 ), their use requires adequate self-awareness on the part of the respondent, and some children who are bullied may be in denial about their experience of having been bullied.

There is also evidence of gender differences in the physical effects of being bullied. For example, Kowalski and Limber (2013) examined the relation between experiences with cyberbullying or traditional bullying (i.e., bullying that does not involve digital electronic means of communication) and psychological and physical health, as well as academic performance, of 931 students in grades 6 through 12 living in rural Pennsylvania. Students were asked how often in the past 4 weeks they experienced 10 physical health symptoms, with scores across these 10 symptoms averaged to provide an overall health index (higher scores equal more health problems). Traditional bullying was defined as “aggressive acts that are meant to hurt another person, that happen repeatedly, and that involve an imbalance of power” ( Kowalski and Limber, 2013 , p. S15). The authors found that girls who were traditionally bullied reported more anxiety and overall health problems than boys who were bullied (females: M = 1.65, SD = 0.41; males: M = 1.42, SD = 0.38). A limitation of this study is that it is correlational in nature and the authors cannot conclude that being a victim of traditional bullying caused the psychological or physical problems.

In summary, it is clear that children and youth who have been bullied also experience a range of somatic disturbances. There are also gender differences in the physical health consequences of being bullied.

Neuroendocrinology of Stress

Psychological and physical stressors, such as being the target of bullying, activate the stress system centered on the hypothalamic-pituitary-adrenal (HPA) axis ( Dallman et al., 2003 ; McEwen and McEwen, 2015 ). The role of HPA and other hormones is to promote adaptation and survival, but chronically elevated hormones can also cause problems. Stress has ubiquitous effects on physiology and the brain, alters levels of many hormones and other biomarkers, and ultimately affects behavior. Therefore, both a general understanding of stress during early adolescence and, where known, specific links between stress and bullying can provide insight into the enduring effects of bullying.

The levels of the stress hormone cortisol have been shown to change in targets of repeated bullying, with being bullied associated with a blunted cortisol response ( Booth et al., 2008 ; Kliewer, 2006 ; Knack et al., 2011b ; Ouellet-Morin et al., 2011 ; Vaillancourt et al., 2008 ). To the committee's knowledge, no study has examined bidirectional changes in cortisol, although there is evidence to suggest that cortisol is typically elevated immediately following many types of stress and trauma but blunted after prolonged stress ( Judd et al., 2014 ; Miller et al., 2007 ). Kliewer (2006) did find that cortisol increased from pre-task to post-task (i.e., watching a video clip from the film Boyz 'n the Hood followed by a discussion) among youth who had been bullied, and in a more recent study, Kliewer and colleagues (2012) reported, among African American urban adolescents, that peer victimization was associated with greater sympathetic nervous system (fight or flight reaction) reactivity to a stress task (measured using salivary a-amylase, an enzyme that increases in saliva when the sympathetic nervous system is activated). However, in these studies, the immediate effect of being bullied on stress reactivity was not examined. In contrast, Ouellet-Morin and colleagues (2011) and Knack and colleagues (2011b) did not find an increase in cortisol in bullied youth following a psychosocial stress test but rather found a blunted pattern of response after the test had concluded (see Figures 4-1 and 4-2 ). In order to test whether, in the short-term, bullying produces an increase in cortisol, whereas in the long-term it is associated with a blunted cortisol response (as seen with other types of psychosocial stressors; Judd et al., 2014 ; Miller et al., 2007 ), a longitudinal study is needed to examine bullying chronicity and regulation of the HPA axis. The importance of this future work notwithstanding, there is evidence to support a finding that when stress becomes prolonged, the stress hormone system becomes hypofunctional and a blunted stress response results ( McEwen, 2014 ).

Cortisol reactivity for victimized and nonvictimized adolescents during the Trier Social Stress Test. SOURCE: Adapted from Knack et al. (2011b, Fig. 3, p. 5).

Cortisol responses to a psychosocial stress test (PST) in the total sample and according to maltreatment/bullying victimization. SOURCE: Adapted from Ovellet-Morin et al. (2011, Fig. 1, p. 14).

When stress becomes prolonged, the stress hormone system becomes hypofunctional and a blunted stress response results ( Knack et al., 2012a ; McEwen, 2014 ; Vaillancourt et al., 2013a ). That is, the elevation in cortisol in response to stress fails to occur. Scientists are not exactly sure how this happens, but evidence suggests that the stress system has shut itself down through “negative feedback.” Although on the surface this may seem to be beneficial, it is not. Cortisol has many functions and serves to regulate myriad biological systems; a blunted stress response compromises the orchestration of cortisol's biological functions. The critical importance of the massive over-activation of the stress system producing a blunted stress response is clinically relevant since it is associated with posttraumatic stress disorder and other psychiatric disorders ( Heim et al., 1997 ). It is also relevant for understanding an individual's inability to self-regulate and cope with stress.

Prolonged stress also disrupts the circadian or daily rhythm of cortisol, which is normally elevated in the morning and slowly decreases over the day to result in low levels at bedtime ( Barra et al., 2015 ). An altered circadian rhythm results not only in difficulty awaking in the morning but also in difficulty falling asleep at night. It can cause profound disruption in sleep patterns that can initiate myriad additional problems; sleep deficits are associated with problems with emotional regulation, learning, mood disorders, and a heightened social threat detection and response system ( McEwen and Karatsoreos, 2015 ). Recent research suggests that the consolidation of memories 2 one learns each day continues during sleep ( Barnes and Wilson, 2014 ; Shen et al., 1998 ). Sleep disturbances disrupt memory consolidation, and studies in animals suggest stress during learning engages unique neurochemical and molecular events that cause memory to be encoded by some unique mechanism ( Baratta et al., 2015 ; Belujon and Grace, 2015 ; McGaugh, 2015 ; Rau and Fanselow, 2009 ). Although victims of bullying have sleep problems ( Miller-Graff et al., 2015 ), causal relations between bullying, sleep disorders, learning/memory consolidation, and cortisol dysregulation have not been established. Indeed, these correlations between being a target of bullying and physiological problems may highlight important interactions between events and outcome, but it is also likely that unidentified variables might be the critical causal factors.

It is also noteworthy that the HPA axis showed heightened responsiveness during the peak ages of bullying ( Blakemore, 2012 ; Dahl and Gunnar, 2009 ; Romeo, 2010 ; Spear, 2010 ). For example, cortisol response characteristics in children are such that, when cortisol is activated, the hormonal response is protracted and takes almost twice as much time to leave the blood and brain compared to adults ( Romeo, 2010 , 2015 ). The circadian rhythm of cortisol also seems altered during early adolescence, most notably associated with morning cortisol levels, with levels increasing with age and pubertal development ( Barra et al., 2015 ). Animal models suggest that the extended cortisol response begins in pre-puberty and indicate that recovery from stressful events is more challenging during this age range ( Romeo, 2015 ).

Emotional regulation, including a person's ability to recover from a traumatic or stressful event, involves being able to regulate or normalize stress hormone levels. Before adolescence, children's ability to regulate their stress response can be greatly assisted by parents or other significant caregivers—a process referred to as “social buffering” ( Hostinar et al., 2014 ; Ouellet-Morin et al., 2011 , 2013 ). Specifically, it is well documented in the human and animal research literature that a sensitive caregiver or a strong support system can greatly dampen the stress system's response and actually reduce the amount of stress hormone released, as well as shorten the amount of time the stress hormones circulate within the body and brain. This results in dramatic decreases in stress-related behavior ( Gee et al., 2014 ; Hostinar et al., 2014 ). The social cues actually reduce stress by reducing the activation of the stress system, or HPA axis, at the level of the hypothalamus ( Hennessy et al., 2009 , 2015 ; Moriceau and Sullivan, 2006 ). The social stimuli that buffer children as they transition into adolescence appear to begin to have greater reliance on peers rather than on the caregiver ( Hostinar et al., 2015 ).

Other physiological effects of stress include the activation of the immune system by bullying-induced stress ( Copeland et al., 2014 ; McCormick and Mathews, 2007 ), and a cardiovascular blunting among individuals with a history of being bullied ( Newman, 2014 ). Other hormones and physiological mechanisms are also involved in the stress activation response. For example, cortisol is associated with an increase in testosterone, the male sex hormone associated with aggression in nonhuman animals and with dominance and social challenge in humans, particularly among boys and men ( Archer, 2004 ). In fact, in rodents the combined assessment of testosterone and cortisol provides more predictive value of behavioral variability ( McCormick and Mathews, 2007 ) compared to controls ( Márquez et al., 2013 ). In humans, there is increasing evidence supporting an interaction between testosterone and cortisol in the prediction of social aggression (see Montoya et al., 2012 ). In a study of 12-year-olds, Vaillancourt and colleagues (2009) found that testosterone levels were higher among bullied boys than nonbullied boys, but lower among bullied girls than nonbullied girls. The authors speculated that the androgen dynamics were possibly adrenocortical in origin, highlighting the need to examine testosterone and cortisol in consort. To date, researchers have only investigated cortisol response to being bullied ( Kliewer, 2006 ; Knack et al., 2011b ; Ouellet-Morin et al., 2011 ; Vaillancourt et al., 2008 ), and only one study has examined testosterone and peer victimization ( Vaillancourt et al., 2009 ). There are no studies examining these two important hormones together in relation to bullying perpetration or to being bullied.

Together, the research on both humans and animals suggests that stress is beneficial when it is experienced at low-to-moderate levels, whereas prolonged or repeated stress becomes toxic by engaging a unique neural and molecular cascade within the brain that is thought to initiate a different developmental pathway. Indeed, from animal models, brain architecture is altered by chronic stress, with amygdala activity being enhanced, hippocampal function impaired, and medial prefrontal cortex function being reduced, leading to increased anxiety and aggression and decreased capacity for self-regulation, as well as a more labile mood ( Chattarji et al., 2015 ; McEwen and Morrison, 2013 ; McEwen et al., 2015 ). This stress effect on the brain is particularly strong when experienced during adolescence, but it is even more pronounced if combined with early life adversity ( Gee et al., 2014 ; Hanson et al., 2015 ; Richter-Levin et al., 2015 ; Romeo, 2015 ; Sandi and Haller 2015 ). This could produce behavioral responses that become maladaptive by compromising emotional and cognitive functioning or perhaps it could produce adaptive behavior for a dangerous environment that results in socially inappropriate behavior.

Consequences of Bullying on Brain Function

Being a child or youth who is bullied changes behavior, and neuroscience research suggests this experience may also change the brain ( Bradshaw et al., 2012 ; Vaillancourt et al., 2013a ). The major technique used to monitor brain function in humans is functional magnetic resonance imaging (fMRI), which works by monitoring blood flow to indirectly assess the functioning of thousands of brain cells over an area of the brain. This technique has rarely been used on either the perpetrator or target of a bullying incident during this very particular social interaction, and for that reason little is known about whether or not the brain of a child who bullies or of a child who has been bullied is different before these experiences or is changed by them. These very specific studies are required before one can make definitive statements about the brain for this topic or for how this information might help develop novel interventions or prevention.

Additionally, it is important to consider two limitations for understanding fMRI. First, one cannot scan the brain of a child during the action of bullying or being a target of bullying. Instead, one must rely on the child staying perfectly still as the investigator tries to approximate one or two aspects of the complex experience that occur in this complicated behavioral interaction. For example, the fMRI task used during a brain imaging session might mimic social exclusion as one facet of bullying, without the full social and emotional context of the real bullying process. Although this is an important methodology, these results need to be assessed with caution at this time and not directly applied as an accepted scientific interpretation of bullying. Therefore, the examples used below to assess brain function rely not on monitoring actual instances of bullying behavior but on monitoring components of behaviors that are thought to occur during a bullying incident.

Second, fMRI monitors a large brain area, which is composed of many smaller brain areas, each of which is involved in many, many behaviors, many of which are not yet fully understood. Thus, it is difficult to determine why the brain area one is examining changed, since that brain area is involved in hundreds of diverse behaviors. For this reason, the results reviewed below need to be viewed as preliminary and should not be misinterpreted as explaining any aspect of the experience of bullying. Rather, these preliminary results highlight the importance of brain assessment before and after bullying experiences, including developing monitorable tasks that more closely approximate the bullying experience within the physical constraints of an immobile subject during an fMRI brain scan. The value of neuroscience is that it enables exploration of brain mechanisms controlling behavior that are not obvious from behavioral assessment.

Social Pain

Whereas there are no studies directly examining bullying using neural imaging techniques, there are several studies examining how the brain processes social pain. Social pain describes the “feelings of pain that follow the experiences of peer rejection, ostracism, or loss” ( Vaillancourt et al., 2013a , p. 242). Social pain is consistent with how people describe their feeling about being bullied. For example, one victim of bullying described the emotional toll of his experience by saying, “I feel like, emotionally, they [his bullies] have been beating me with a stick for 42 years” ( Vaillancourt et al., 2013a , p. 242).

Researchers have demonstrated that when people experience social pain, they activate regions in their brain similar to those activated when they experience physical pain ( Eisenberger, 2012 ; Eisenberger and Lieberman, 2004 ; Eisenberger et al., 2003 ; Kross et al., 2011 ; Vaillancourt et al., 2010a ). Specifically, the dorsal anterior cingulate cortex, which is part of the prefrontal cortex, seems to be implicated in the processing of both physical and social pain. The fact that physical and social pain have overlapping neural systems might explain why people tend to use physical pain metaphors (e.g., “It broke my heart when she called me ugly.”) when describing their experiences with being humiliated, oppressed, or rejected ( Eisenberger, 2012 ). Eisenberger and Leiberman (2004) noted that these fMRI results are correlations between pain and the anterior cingulate cortex and could reflect other functions of that brain region, such as detecting conflict or errors, different ideas or goals about the task, or individual differences in the task difficulty. In a recent fMRI study by Rudolph and colleagues (2016) , adolescent girls were socially excluded during a laboratory task (i.e., cyberball; Williams et al., 2000 ). Results indicated that activation of the social pain network—the dorsal anterior cingulate cortex, subgenual anterior cingulate cortex, and anterior insula—was associated with internalizing symptoms. Of note, this effect was particularly pronounced among adolescent girls with a history of peer victimization. 3

In addition to studies on social pain, there are some studies examining how the brains of children who had been bullied reacted subsequently to different stimuli. Experiences of being bullied can alter an individual's view of the world. While no brain imaging study has directly addressed this issue, a longitudinal study investigating the risk factors of depression found that being a child who was bullied at ages 11 and 12 was associated with a decreased response to reward in the medial prefrontal cortex at age 16, although it was unclear if these brain differences were present before the bullying experiences or developed after them ( Casement et al., 2014 ). The medial prefrontal cortex, which is a brain area involved in memory and learning, was found to be disrupted in children who have been bullied ( Vaillancourt et al., 2011 ). Because it also has countless other functions including decision making, risk taking, and conflict monitoring, disruption of this region compromises one's ability to interpret results with respect to bullying ( Euston et al., 2012 ; Vaillancourt et al., 2011 ).

In another fMRI study involving children, 10-12 years old, who were presented with a task that examined their response to negative feedback stimuli of emotional faces, greater and more extensive brain activation was found in the amygdala, orbitofrontal cortex, and ventrolateral prefrontal cortex of children who had been rejected by their peers, compared with children in a control group who had not been rejected by peers ( Lee et al., 2014 ), a condition that is highly correlated with being bullied by peers ( r = .57; Knack et al., 2012a ). The prefrontal cortex is a very large brain area with many subareas, all of which serve diverse functions in many different behaviors, not just executive function. Indeed, the prefrontal cortex processes pain, self-regulation, stress integration, and safety signals and has been implicated in psychiatric disorders, higher order learning, extinction (active process to suppress a memory), personality, social behavior, planning, decision making, and many other behaviors and percepts including social exclusion, social/physical pain, and empathy ( Casey and Jones, 2010 ; Spear, 2013 ). These few studies are consistent with other imaging studies demonstrating functional brain differences among individuals who were maltreated in childhood ( Lim et al., 2014 , 2015 ). Taken together, this work supports a finding that being exposed to such adversity during maturation has enduring effects on brain function, although additional research is needed to establish the parameters controlling these effects (and qualifying the generalization).

There is also evidence that stressful events, such as might occur with bullying experiences, impact emotional brain circuits, an inference that is supported by changes in amygdala architecture and function described earlier in animal models in adulthood but more robust changes in brain structure are produced by stress during early life and around adolescence ( Chattarji et al., 2015 ; McEwen and Morrison, 2013 ; McEwen et al., 2015 ). This point is critical because the stress system of adolescents seems to have a heightened sensitivity, and experiencing bullying can increase stress hormones ( Romeo, 2010 , 2015 ; Spear, 2013 ; Vaillancourt et al., 2011 ). Human brain scanning experiments suggest the prefrontal cortex is affected by stress through attenuating the connectivity to the hippocampus and amygdala, which are brain areas critical for emotional regulation and emotional memories ( Ganzel et al., 2008 ; Liston et al., 2009 ). Animal research shows that this connectivity loss is caused by stress-induced atrophy of the prefrontal cortex ( Radley et al., 2006 ), although this brain region does show the ability to recover once the stress has terminated ( Liston et al., 2009 ). One aspect of being a target of bullying is that the memory of the experience seems to be enduring; the unique function of the prefrontal cortex and emotional circuits during preadolescence and adolescence may provide insight into the enduring memories of being bullied. Specifically, one function of the prefrontal cortex is to help suppress memories that are no longer important or true. Typically, memories are not simply forgotten or unlearned. Rather, as we update information in our brain, the old memory is suppressed by overlaying a new memory to attenuate the old memory, an active brain process called extinction ( Milaid and Quirk, 2012 ). With respect to memories of trauma, of being bullied, or of experiencing a threat, the prefrontal cortex is important for attenuating (extinguishing) memories in emotional brain areas, such as the amygdala. Importantly, dramatic changes occur in the extinction system during adolescence, where fear extinction learning is attenuated relative to children and adults ( Pattwell et al., 2012 , 2013 ). This learning mode has been modeled in animals to understand how the process occurs in the adolescent brain ( Kim and Richardson, 2010 ; Nair and Gonzalez-Lima, 1999 ; Pattwell et al., 2012 ). The research suggests that around the time of adolescence, it is more difficult to decrease emotionally aversive memories, such as experiences of being bullied, than at other times in the life cycle. Furthermore, anxious teens (anxiety is sometimes comorbid with experience of being bullied) show even greater difficulties with processing extinction of fear memory ( Jovanovic et al., 2013 ).

In conclusion, the available evidence indicates that the brain functioning of individuals who are bullied is altered (see reviews by Bradshaw et al., 2012 ; Vaillancourt et al., 2013a ). However, it is difficult to ascertain fully what it means when fMRI scans detect an alteration in brain activity. In terms of understanding the prolonged and repeated stress associated with bullying, this research suggests that greater experience with being bullied and repeated exposure as a target of bullying produces a neural signature in the brain that could underlie some of the behavioral outcomes associated with being bullied.

Psychosocial Consequences

In this section, the committee examines what is known about the psychosocial consequences of being bullied. A common method of examining mental health issues separates internalizing and externalizing problems ( Sigurdson et al., 2015 ). Internalizing symptoms include problems directed within the individual, such as depression, anxiety, fear, and withdrawal from social contacts. Externalizing symptoms reflect behavior that is typically directed outwards toward others, such as anger, aggression, and conduct problems, including a tendency to engage in risky and impulsive behavior, as well as criminal behavior. Externalizing problems also include the use and abuse of substances.

Psychological problems are common after being bullied (see review by Hawker and Boulton, 2000 ) and include internalizing problems, such as depression, anxiety, and, especially for girls, self-harming behavior ( Kidger et al., 2015 ; Klomek et al., 2009 , 2015 ). There can also be subsequent externalizing problems, especially for boys (see review by McDougall and Vaillancourt, 2015 ). Rueger and colleagues (2011) found consistent concurrent association with timing of peer victimization and maladjustment. Both psychological and academic outcomes were particularly strong for students who experienced sustained victimization over the school year.

“And these are the kids that are at risk for anxiety and depression and bipolar disorder to begin with, and it almost seems like it's a cycle that makes it worse. So they are isolated and they are angry, they are fearful. Many of them end up severely depressed, attempting suicide, utilizing NSSIs [nonsuicidal self-injuries] for comfort. Some turn to gangs because that is the group that would accept them. So that's when we get involved and we have to start working backwards.”

—Quote from community-based provider discussing bullying during focus group (See Appendix B for additional highlights from interviews.)

Internalizing Problems

A robust literature documents that youth who are bullied often have low self-esteem and feel depressed, anxious, and lonely ( Juvonen and Graham, 2014 ). Data from developmental psychopathology research indicate that stressful life events can lead to the onset and maintenance of depression, anxiety, and other psychiatric symptoms and that for many youth, being bullied is a major life stressor ( Swearer and Hymel, 2015 ). Based on sociometric nominations, targets of bullying also are disliked by the general peer group ( Knack et al., 2012b ).

Several meta-analyses have specifically explored the relation between depression and being bullied at school ( Ttofi et al., 2011 ) and victimized by peers 4 ( Hawker and Boulton, 2000 ; Reijntjes et al., 2010 ). Individuals who had been cyberbullied reported higher levels of depression and suicidal ideation, as well as increased emotional distress, externalized hostility, and delinquency, compared with peers who were not bullied ( Patchin, 2006 ; Ybarra et al., 2006 ). Furthermore, severity of depression in youth who have been cyberbullied has been shown to correlate with the degree and severity of cyberbullying ( Didden et al., 2009 ).

Two meta-analyses found that across several different longitudinal studies using different study populations, internalizing emotional problems increases both the risk and the harmful consequences of being bullied ( Cook et al., 2010 ; Reijntjes et al., 2010 ). Internalizing problems can thus function as both antecedents and consequences of bullying ( Reijntjes et al., 2010 ; Vaillancourt et al., 2013b ). Although most longitudinal studies suggest that psychological problems result from being bullied (see review by McDougall and Vaillancourt, 2015 ) and meta-analyses ( Reijntjes et al., 2010 ; Ttofi et al., 2011 ) support this directionality, there is some evidence that for some youth, the temporal pattern begins with mental health problems ( Kochel et al., 2012 ; Vaillancourt et al., 2013b ).

In a large cohort of Canadian children followed every year from grade 5 to grade 8, Vaillancourt and colleagues (2013b) found that internalizing problems in grades 5 and 7 predicted increased self-reported bullying behavior the following year. They noted that these findings provide evidence for the “symptom-driven pathway” across time with increased internalizing problems predicting greater self-reported peer victimization. This “symptom-drive pathway” was noted from grade 5 to grade 6 and again from grade 7 to grade 8 and was consistent with other published work. For instance, Kochel et al. (2012) reported a symptom-driven pathway in which depressive symptoms predicted peer victimization 5 1 year later (grade 4 to grade 5 and grade 5 to grade 6) and argued that this pathway may result from depressed youth displaying “social deficits,” selecting “maladaptive relationships,” and/or displaying a behavioral style that is perceived poorly by the peer group ( Kochel et al., 2012 , p. 638). Vaillancourt and colleagues (2013b) have also argued that depressed youth could be more “treat sensitive.” That is, these youth may select information from their environment that is consistent with their negative self-opinion. The idea that certain individuals may be more sensitive to environmental cues or make more hostile interpretation of ambiguous social data has been well documented in the literature ( Crick and Dodge, 1994 ; Dodge, 1986 ). This work is consistent with studies showing that social information processing differs in children based on their experience with being bullied and that hypersensitivity can impact their interpretation of social behavior and their self-reports of subsequent incidents of being bullied ( Camodeca et al., 2003 ; Smalley and Banerjee, 2013 ).

Most longitudinal studies to date are of relatively short duration (i.e., less than 2 years) and focus on a narrow developmental period such as childhood or adolescence ( McDougall and Vaillancourt, 2015 ). Nevertheless, there are several recently published studies examining the long-term adult outcomes of childhood bullying. These studies indicate that being bullied does affect future mental health functioning, as reviewed in the following paragraphs.

Most long-term studies of childhood bullying have focused on links to internalizing problems in adulthood, demonstrating robust long-standing effects ( Gibb et al., 2011 ; Olweus, 1993b ; Sourander et al., 2007 ; Stapinski et al., 2014 ). For example, Bowes and colleagues (2015) examined depression in a large sample of participants who reported being the target of bullying at age 13 and found higher rates of depression at age 18 compared to peers who had not been bullied. Specifically, they reported that 14.8 percent of participants who reported being frequently bullied in childhood at age 13 were clinically depressed at age 18 ( OR = 2.96, 95% CI [2.21, 3.97]) and that the population attributable fraction was 29.2 percent, suggesting that close to a third of the variance in depression could be explained by being bullied in childhood ( Bowes et al., 2015 ).

In another longitudinal study using two large population-based cohorts from the United Kingdom (the ALSPAC Cohort) and the United States (the GSMS Cohort), Lereya and colleagues (2015) reported that the effects of childhood bullying on adult mental health were stronger in magnitude than the effects of being maltreated by a caregiver in childhood. Being bullied only (and not maltreated) placed individuals at higher risk for mental health difficulties than being maltreated only (and not bullied) ( OR = 1.6, 95% CI [1.1, 2.2] for ALSPAC cohort; OR = 3.8, 95% CI [1.8, 7.9] for GSMS cohort). Children who were bullied were more likely than maltreated children to be anxious ( OR = 4.9, 95% CI [2.0, 12.0] for GSMS cohort), depressed ( OR = 1.7, 95% CI [1.1, 2.7] for ALSPAC cohort), and to engage in self-harming behavior ( OR = 1.7, 95% CI [1.1-2.6] for ALSPAC cohort) in adulthood ( Lereya et al., 2015 ).

Similarly, Stapinski and colleagues (2014) found that adolescents who experienced frequent peer victimization 6 were two to three times more likely to develop an anxiety disorder 5 years later at age 18 than nonvictimized adolescents ( OR = 2.49, 95% CI [1.62, 3.85]). The association remained after adjusting for potentially confounding individual and family factors and was not attributable to diagnostic overlap with depression. Frequently victimized adolescents were also more likely to develop multiple internalizing problems in adulthood ( Stapinski et al., 2014 ). After controlling for childhood psychiatric problems or family hardship, Copeland and colleagues (2013) found that individuals who were bullied continued to have higher prevalence of generalized anxiety ( OR = 2.7, 95% CI [1.1, 6.3]).

These findings suggest that being bullied and internalizing problems such as depression are mutually reinforcing, with the experience of one increasing the risk of the other in a harmful cycle that contributes to the high stability of being both bullied and experiencing other internalizing problems. These studies also suggest that the long-term consequences of being bullied, which extend into adulthood, can be more severe than being maltreated as a child by a caregiver.

Externalizing Problems

Alcohol and drug abuse and dependence have been associated with being bullied as a child ( Radliff et al., 2012 ). A longitudinal study of adolescents found that those who reported being bullied were more likely to report use of alcohol, cigarettes, and inhalants 12 months later ( Tharp-Taylor et al., 2009 ), compared to those who did not report being bullied. More longitudinal research that tracks children through adulthood is needed to fully understand the link between being bullied and substance abuse (see review by McDougall and Vaillancourt, 2015 ).

Several studies show links between being bullied and violence or crime, especially for men ( Gibb et al., 2011 ; McGee et al., 2011 ; Sourander et al., 2007 , 2011 ). A meta-analysis by Reijntjes and colleagues (2011) that included studies with data on 5,825 participants showed that after controlling for externalizing symptoms at baseline, peer victimization—under which they included being the target of teasing, deliberate exclusion, and being the target of physical threats and malicious gossip—was associated over time with exhibiting externalizing problems such as aggression, truancy, and delinquency ( r = .14, 95% CI [.09, .19]). This research team also found that externalizing problems predicted changes in peer victimization over time ( r = .13, 95% CI [.04, .21]) and concluded that there is a bidirectional relationship between peer victimization and externalizing problems.

Psychotic Symptoms

Evidence from the broader research on childhood trauma and stress indicates that earlier adverse life experiences, such as child abuse, are associated with the development of psychotic symptoms later in life ( Institute of Medicine and National Research Council, 2014b ). Until recently, the association between bullying and psychotic symptoms has been understudied ( van Dam et al., 2012 ). Two recent meta-analyses support the association between bullying and the development of psychotic symptoms later in life ( Cunningham et al., 2015 ; van Dam et al., 2012 ). van Dam and colleagues (2012) conducted a meta-analysis of 14 studies to assess whether being bullied in childhood is related to the development of psychotic (either clinical or nonclinical) symptoms. (Nonclinical psychotic symptoms 7 place individuals at risk for the development of psychotic disorders ( Cougnard et al., 2007 ).) Results from the analyses of studies that examined the association between bullying and nonclinical symptoms (six studies) were more definitive (adjusted OR = 2.3; 95% CI [1.5, 3.4]), with stronger associations when there was an increased frequency, severity, and persistence of bullying ( Cougnard et al., 2007 ). Although some research has found this association, a recent longitudinal study from New Zealand found that the link between bullying and the development of psychosis later in life is likely not causal but instead reflects the fact that individuals who display disordered behaviors across childhood and adolescences are more likely to become bullying targets ( Boden et al., 2016 ) An analysis of studies that examined the association between bullying and psychosis in clinical samples was inconclusive ( van Dam et al., 2012 ).

A recent meta-analysis conducted by Cunningham and colleagues (2015) examined ten European prospective studies, four from the Avon Longitudinal Study of Parents and Children. This analysis found that individuals who were bullied were more than twice as likely to develop later psychotic symptoms, compared to those who were not bullied ( OR = 2.1, 95% CI [1.1, 4.0]). These results were consistent in all but one of the studies included in the meta-analysis. More longitudinal research is needed to more fully understand the mechanisms through which trauma such as bullying may lead to the development of psychotic symptoms ( Cunningham et al., 2015 ; van Dam et al., 2012 ). Importantly, this research will need to be prospective and examine the development of bullying and psychotic symptoms in order to truly identify the temporal priority. The inclusion criteria for the Cunningham and colleagues (2015) meta-analysis included that the study had to be prospective and had to include a measure of psychosis and that bullying needed to be reported before the age of 18. Although the authors stated that “bullying appears to cause later development of psychosis,” such a conclusion requires that mental health functioning be assessed early and over time, as it is possible that premorbid characteristics may make individuals targets for poor peer treatment (see Kochel et al., 2012 ; Vaillancourt et al., 2013b , regarding depression leading to peer victimization).

Academic Performance Consequences

A growing literature has documented that targets of bullying suffer diminished academic achievement whether measured by grades or standardized test scores ( Espelage et al., 2013 ; Nakamoto and Schwartz, 2010 ). Cross-sectional research indicates that children who are bullied are at increased risk for poor academic achievement ( Beran, 2009 ; Beran and Lupart, 2009 ; Beran et al., 2008 ; Glew et al., 2005 ; Neary and Joseph, 1994 ; see also meta-analysis by Nakamoto and Schwartz, 2010 ) and increased absenteeism ( Juvonen et al., 2000 ; Kochenderfer and Ladd, 1996 ; Vaillancourt et al., 2013b ).

The negative relation between being bullied and academic achievement is evident as early as kindergarten ( Kochenderfer and Ladd, 1996 ) and continues into high school ( Espinoza et al., 2013 ; Glew et al., 2008 ). In a 2-week daily diary study with ninth and tenth grade Latino students, Espinoza and colleagues (2013) reported that on days when adolescents' reports of being bullied were greater than what was typical for them, they also reported more academic challenges such as doing poorly on a quiz, test, or homework and felt like less of a good student. Thus, even episodic encounters of being bullied can interfere with a student's ability to concentrate on any given day. In a cross-sectional study of more than 5,000 students in grades 7, 9, and 11, Glew and colleagues (2008) found that for every 1-point increase in grade point average (GPA), the odds of being a child who was bullied (versus a bystander) decreased by 10 percent. However, due to the cross-sectional nature of this study, this association does not establish whether lower academic achievement among children who were bullied was a consequence of having been bullied.

Several short-term (one academic year) longitudinal studies indicate that being bullied predicts academic problems rather than academic problems predicting being a target of bullying ( Kochenderfer and Ladd, 1996 ; Schwartz et al., 2005 ). Given the impairments in brain architecture associated with self-regulation and memory in animal models and the currently limited imaging data in human subjects, this is a reasonable inference, although reverse causation is possible. For instance, early life abuse and neglect impair these same abilities, lower self-esteem, and may make an individual more likely to be a target of bullying. In one of the few longitudinal studies to extend beyond one year, Juvonen and colleagues (2011) examined the relation between victimization 8 and academic achievement across the three years of middle school. Academic adjustment was measured by both year-end grades and teacher reports of engagement. These authors found that more self-reported victimization was related to lower school achievement from sixth to eighth grade. For every 1-unit increase in victimization (on a 1-4 scale), GPA declined by 0.3 points.

Other short-term longitudinal studies found similar results. For example, Nansel and colleagues (2003) found that being bullied in a given year (grade 6 or 7) predicted poor academic outcomes the following year, after controlling for prior school adjustment and if they were previously targets of bullying or not. Similarly, Schwartz and colleagues (2005) reported a negative association for third and fourth grade children between victimization 9 and achievement 1 year later. In addition, Baly and colleagues (2014) found that the cumulative impact of being bullied over 3 years from sixth grade to eighth grade had a negative impact on GPA and standardized test scores.

However, other studies have not found such associations. For instance, Kochenderfer and Ladd (1996) found no relation between being bullied and subsequent academic achievement in their study of students assessed in the fall and spring of kindergarten, nor did Rueger and Jenkins (2014) in their study of seventh and eighth graders assessed in the fall and spring of one academic year. Feldman and colleagues (2014) also reported no association between being a target of bullying and academic achievement in their 5-year longitudinal study of youth ages 11-14. Poor academic performance can also be a predictor of peer victimization ( Vaillancourt et al., 2013b ). The authors found that poor writing performance in third grade predicted increased bullying behavior in fifth grade that was stable until the end of eighth grade.

The longitudinal associations between peer victimization and school attendance are also equivocal, with some showing positive associations ( Baly et al., 2014 ; Buhs et al., 2006 ; Gastic, 2008 ; Kochenderfer and Ladd, 1996 ; Smith et al., 2004 ) and others not finding a statistically significant association ( Forero et al., 1999 ; Glew et al., 2008 ; Rueger et al., 2011 ; Vaillancourt et al., 2013b ). 10

In summary, there have been a number of cross-sectional and longitudinal studies that have provided support for a relation between being bullied and increased risk for poor academic achievement. However, given the inconsistent results found with longitudinal studies, more research is warranted in this area to more fully ascertain the relation between being bullied and academic achievement over time.

• CONSEQUENCES FOR INDIVIDUALS WHO BULLY

There is evidence that supports a finding that individuals who bully others have contradictory attributes ( Institute of Medicine and National Research Council, 2014a ; Vaillancourt et al., 2010b ). Research suggests that there are children and adolescents who bully others because they have some form of maladjustment ( Olweus, 1993a ) or, as mentioned in Chapter 3 , are motivated by establishing their status in a social network ( Faris and Ennett, 2012 ; Rodkin et al., 2015 ; Sijtsema et al., 2009 ; Vaillancourt et al., 2003 ). Consequently, the relation between bullying, being bullied, acceptance, and rejection is complex ( Veenstra et al., 2010 ). This complexity is also linked to a stereotype held by the general public about individuals who bully. This stereotype casts children and youth who bully others as being high on psychopathology, low on social skills, and possessing few assets and competencies that the peer group values ( Vaillancourt et al., 2010b ). Although some occurrence of this “stereotypical bully” or “classic bully” is supported by research ( Kumpulainen et al., 2001 ; Olweus, 1993a ; Sourander et al., 2007 ), when researchers consider social status in relation to perpetration of bullying behavior, a different profile emerges. These studies suggest that most children and youth who bully others wield considerable power within their peer network and that high-status perpetrators tend to be perceived by peers as being popular, socially skilled, and leaders ( de Bruyn et al., 2010 ; Dijkstra et al., 2008 ; Peeters et al., 2010 ; Thunfors and Cornell, 2008 ; Vaillancourt et al., 2003 ). High-status bullies have also been found to rank high on assets and competencies that the peer group values such as being attractive or being good athletes ( Farmer et al., 2003 ; Vaillancourt et al., 2003 ); they have also been found to rank low on psychopathology and to use aggression instrumentally to achieve and maintain hegemony (for reviews, see Rodkin et al., 2015 , and Vaillancourt et al., 2010b ). Considering these findings of contrasting characteristics of perpetrators of bullying behavior, it makes sense that the research on outcomes of perpetrating is mixed. Unfortunately, most research on the short- and long-term outcomes of perpetrating bullying behavior has not taken into account this heterogeneity when considering the impact to children and youth who have bullied their peers.

Psychosomatic Consequences

Findings from cross-sectional studies that reported data on individuals who bullied others have shown that these individuals are at risk of developing psychosomatic problems ( Gini, 2008 ; Srabstein et al., 2006 ). Gini and Pozzoli (2009) conducted a meta-analysis to test whether children involved in bullying behavior in any role are at risk for psychosomatic problems. They included studies ( n = 11) that examined the association between bullying involvement and psychosomatic complaints in children and adolescents between the ages of 7 and 16. The studies included in the meta-analysis used self-report questionnaires; reports from peers, parents, or teachers; and clinical interviews that resulted in a clinical rating of the subject's behaviors and health problems. The included studies also had enough information to calculate effect sizes. An analysis of six studies that met the selection criteria revealed that children who bully had a higher risk ( OR = 1.65, 95% CI [1.34, 2.04]) of exhibiting psychosomatic problems than their uninvolved peers.

This meta-analysis was limited because of its inclusion of cross-sectional and observational studies. Such studies do not allow firm conclusions on cause and effect; hence, the association between bullying perpetration and psychosomatic problems may be difficult to interpret. The methodologies used in the studies make them susceptible to bias and misclassification due to the reluctance of individuals who bully to identify themselves as perpetrators of bullying behavior. Also, the different forms of victimization included in the underlying studies were not reported in this meta-analysis. Additional research is needed to examine the involvement in perpetrating bullying behavior and its short- and long-term psychosomatic consequences.

Psychotic Problems

Using a population-based cohort study, Wolke and colleagues (2014) examined whether bullying perpetration and being a target of bullying in elementary school predicted psychotic experiences 11 in adolescence. The authors assessed 4,720 individuals between the ages of 8 and 11 who were involved in bullying either as perpetrators or targets. At age 18, suspected or definite psychotic experiences were assessed using semistructured interviews. After controlling for the child's gender, intelligence quotient at age 8, and childhood behavioral and emotional problems, the researchers found that both individuals who are bullied (child report at age 10: OR = 2.4, 95% CI [1.6, 3.4]; mother report: OR = 1.6, 95% CI [1.1, 2.3]) and individuals who bullied others (child report at age 10: OR = 4.9, 95% CI [1.3, 17.7]; mother report: OR = 1.2, 95% CI [0.46, 3.1]) had a higher prevalence of psychotic experiences at age 18. The authors concluded that “involvement in any role in bullying may increase the risk of developing psychotic experiences in adolescence” ( Wolke et al., 2014 , p. 2208).

In summary, several studies have focused on the consequences of bullying for individuals who are bullied and have also reported more broadly on consequences for perpetrators of aggressive behavior (see Gini and Pozzoli, 2009 ; Lereya et al., 2015 ; Reijntjes et al., 2010 ; Ttofi et al., 2011 ), but the consequences of bullying involvement for individuals who perpetrate bullying behavior have been rarely studied to date. That is, although there is a rich literature on aggressors and the outcomes of being aggressive, there are few studies examining bullying perpetration specifically, taking into account the power imbalance, repetition, and intentionality that differentiates aggression from bullying from other forms of peer aggression. As discussed in Chapter 2 , the available research on the prevalence of bullying behavior focuses almost entirely on the children who are bullied. More research, in particular longitudinal research, is needed to understand the short- and long-term physical health, psychosocial, and academic consequences of bullying involvement on the individuals who have a pattern of bullying others, when those individuals are distinguished from children who engage in general aggressive behavior.

• CONSEQUENCES FOR INDIVIDUALS WHO BULLY AND ARE ALSO BULLIED

Individuals who bully and are also bullied experience a particular combination of consequences that both children who are only perpetrators and children who are only targets also experience, such as comorbidity of both externalizing and internalizing problems, negative perception of self and others, poor social skills, and rejection by the peer group. However, at the same time this combination of roles in bullying is negatively influenced by the peers with whom they are interacting ( Cook et al., 2010 ). After controlling for adjustment problems existing prior to incidents of bullying others or being bullied, a nationally representative cohort study found that young children who have been both perpetrators and targets of bullying tended to develop more pervasive and severe psychological and behavioral outcomes than individuals who were only bullied ( Arseneault et al., 2006 ).

Adolescents who were involved in cyberbullying as both perpetrators and targets have been found to be most at risk for negative mental and physical health consequences, compared to those who were only perpetrators, those who were only targets, or those who only witnessed bullying ( Kowalski and Limber, 2013 ; Nixon, 2014 ). For example, the results from a study by Kowalski and Limber (2013) that examined the relation between children's and adolescents' experiences with cyberbullying or traditional bullying and outcomes of psychological health, physical health, and academic performance showed that students who were both perpetrators and targets had the most negative scores on most measures of psychological health, physical health, and academic performance, when compared to those who were only perpetrators, only targets, or only witnesses of bullying incidents.

Wolke and colleagues (2001) examined the association of direct and relational bullying experience with common health problems and found that students ages 6-9 who bullied others and were also bullied by others had more physical health symptoms than children who were only perpetrators or were not involved in bullying behavior. Hunter and colleagues (2014) evaluated whether adolescents who were involved in bullying experienced sleep difficulties more than adolescents who were not involved. They analyzed surveys that were originally collected on behalf of the UK National Health Service and had been completed by adolescents ages 11-17. Controlling for gender, school-stage, socioeconomic status, ethnicity, and other factors known to be associated with sleep difficulties—alcohol consumption, tea or coffee consumption, and illegal drug use—the authors found that individuals who were both perpetrators and targets in bullying incidents were almost three times more likely ( OR = 2.90, 95% CI [1.17, 4.92]) to experience these sleep difficulties, compared to uninvolved young people. Additional research is needed to identify the mechanisms underlying short- and long-term physical health outcomes of individuals who bully and are also bullied.

There is evidence that individuals who are both perpetrators and targets of bullying have the poorest psychosocial profile among individuals with any involvement in bullying behavior; their psychosocial maladjustment, peer relationships, and health problems are similar to individuals who are only bullied, while their school bonding and substance use is similar to individuals who are only perpetrators ( Graham et al., 2006 ; Nansel et al., 2001 , 2004 ). Individuals who both bully and are also bullied by others experience a greater variety of both internalizing and externalizing symptoms than those who only bully or those who are only bullied ( Kim et al., 2006 ).

Some meta-analyses have examined the association between involvement in bullying and internalizing problems in the school-age population and concluded that that individuals who are both perpetrators and targets of bullying had a significantly higher risk for psychosomatic problems than individuals who were only perpetrators or who were only targets ( Gini and Pozzoli, 2009 ; Reijntjes et al., 2010 ). In their meta-analysis, Gini and Pozzoli (2009) reviewed studies that examined the association between involvement in bullying and psychosomatic complaints in children and adolescents. Analysis of a subgroup of studies ( N = 5) that reported analyses for individuals who bully and are also bullied by others showed that these individuals have a significantly higher risk for psychosomatic problems than uninvolved peers ( OR = 2.22, 95% CI [1.77, 2.77]).

Studies suggest that individuals who bully and who are also bullied by others are especially at risk for suicidal ideation and behavior, due to increased mental health problems (see Holt et al., 2015 , and Box 4-1 ).

Suicidality: A Summary of the Available Meta-Analyses.

Similar to individuals who bully, individuals who bully and are also bullied by others often demonstrate heightened aggression compared with non-involved peers. Compared to these other groups, they are by far the most socially ostracized by their peers, most likely to display conduct problems, and least engaged in school, compared with those who are either just perpetrators or just targets; they also report elevated levels of depression and loneliness ( Juvonen et al., 2003 ). Additional research is needed that examines the unique consequences of those children and youth characterized as “bully-victims” because often they are not separated out from “pure victims” (those who are bullied only) in studies. School shootings are a violent externalizing behavior that has been associated with consequences of bullying behavior in the popular media (see Box 4-2 for additional detail).

Bullying and School Shootings.

Several studies have examined the associations between bullying involvement in adolescence and mental health problems in adulthood and have found that individuals who have bullied others and have also been bullied had increased risk of high levels of critical symptoms of psychosis compared to non-involved peers ( Gini, 2008 ; Sigurdson et al., 2015 ). Research is limited in this area, and the topic warrants further investigation.

• CONSEQUENCES OF BULLYING FOR BYSTANDERS

Bullying cannot be viewed as an isolated phenomenon; it is intertwined within the particular peer ecology that emerges, an ecology constituted of social processes that serve particular functions for the individual and for the group ( Rodkin, 2004 ). Bullying frequently occurs in the presence of children and youth who are bystanders or witnesses. Research indicates that bullying can have significant adverse effects on these bystanders ( Polanin et al., 2012 ).

Bystanders have reported feelings of anxiety and insecurity ( Rigby and Slee, 1993 ) which stemmed, in part, from fears of retaliation ( Musher-Eizenman et al., 2004 ) and which often prevented bystanders from seeking help ( Unnever and Cornell, 2003 ). In a study to explore the impact of bullying on the mental health of students who witness it, Rivers and colleagues (2009) surveyed 2,002 students, ages 12-16 and attending 14 schools in the United Kingdom, using a questionnaire that included measures of bullying at school, substance abuse, and mental health risk. They found that witnessing bullying significantly predicted elevated mental health risks even after controlling for the effect of also being a perpetrator or victim (range of = .07 to .15). They also found that being a witness to the bullying predicted elevated levels (= .06) of substance use. Rivers and Noret (2013) found that, compared to students who were not involved in bullying, those who observed bullying reported more symptoms of interpersonal sensitivity (e.g., feelings of being hurt or inferior), helplessness, and potential suicide ideation.

In conclusion, there is very limited research available on the consequences of witnessing bullying for those children and youth who are the bystanders. Studies of bystander behavior have traditionally sought to understand their motives for participation in bullying ( Salmivalli, 2010 ), their roles ( Lodge and Frydenberg, 2005 ; Salmivalli et al., 1996 ), their behavior (either reinforcing the bully or defending the victim) in bullying situations ( Salmivalli et al., 2011 ), and why observers intervene or do not intervene ( Thornberg et al., 2012 ) from a social dynamic perspective, without exploring the emotional and psychological impact of witnessing bullying. More research is needed to understand these consequences.

MULTIPLE EXPOSURES TO VIOLENCE 12

One subpopulation of school-aged youth that may be at increased risk for detrimental short- and long-term outcomes associated with bullying victimization is poly-victims. Finkelhor and colleagues (2007) coined the terms “poly-victim” and “poly-victimization” to represent a subset of youth who experience multiple victimizations of different kinds—such as exposure to (1) violent and property crimes (e.g., assault, sexual assault, theft, burglary), (2) child welfare violations (child abuse, family abduction), (3) the violence of warfare and civil disturbances, and (4) being targets of bullying behavior—and who manifest high levels of traumatic symptomatology. The identification of a poly-victim is grounded not only in the frequency of the victimization but also in victimization across multiple contexts and perpetrators ( Finkelhor et al., 2007 , 2009 ).

Ford and colleagues (2010) determined that poly-victims were more likely to meet criteria for psychiatric disorder, including being two times more likely to report depressive symptoms, three times more likely to report posttraumatic stress disorder, up to five times more likely to use alcohol or drugs, and up to eight times more likely to have comorbid disorders, compared to youth that did not meet criteria for poly-victimization. Poly-victims often engaged in delinquent behavior, associated with deviant peers ( Ford et al., 2010 ), and were entrenched within the juvenile justice system ( Ford et al., 2013 ). Students who were poly-victims in the juvenile justice system reported higher levels of traumatic symptomatology ( Finkelhor et al., 2005 ). However, it is currently unclear whether being bullied plays a major or minor role in poly-victimization.

• MECHANISMS FOR THE PSYCHOLOGICAL EFFECTS OF BULLYING

In the following sections, the committee describes five potential mechanisms for the psychological effects of bullying behavior for both the children who are bullied and children who bully. These include self-blame, social cognition, emotional dysregulation, genetic predisposition to mental health outcomes and bullying, and telomere erosion. 13

One important mechanism for the psychological effects of bullying is how the targets of bullying construe the reason for their plight ( Graham, 2006 ). For example, a history of bullying and the perception of being singled out as a target might lead an individual to ask “Why me ?” In the absence of disconfirming evidence, some might come to blame themselves for their peer relationship problems. Self-blame and accompanying negative affect can then lead to many negative outcomes, including low self-esteem, anxiety, and depression ( Graham and Juvonen, 1998 ).

The adult rape literature (another form of victimization) highlights a correlation between experiencing rape and self-attributions that imply personal deservingness, labeled characterological self-blame, since they may lead to the person thinking of themselves as chronic victims ( Janoff-Bulman, 1979 ). From an attributional perspective, characterological self-blame is internal and therefore reflects on the self; it is stable and therefore leads to an expectation that harassment will be chronic; and it is uncontrollable, suggesting an inability to prevent future harassment. Attributing negative outcomes to internal, stable, and uncontrollable causes leads individuals to feel both hopeless and helpless ( Weiner, 1986 ). In contrast, behavioral self-blame (e.g., “I was in the wrong place at the wrong time”) implies a cause that is both unstable (the harassment is not expected to occur again) and controllable (there are responses in one's repertoire to prevent future harassment). Several researchers in the adult literature have documented that individuals who make characterological self-blaming attributions for negative outcomes cope more poorly, feel worse about themselves, and are more depressed than individuals who make attributions to their behavior (see Anderson et al., 1994 ). Research with early adolescents also revealed that characterological self-blame for academic and social failure resulted in heightened depression ( Cole et al., 1996 ; Tilghman-Osborne et al., 2008 ).

In the first attribution study focused specifically on bullying, Graham and Juvonen (1998) documented that sixth grade students with reputations as targets made more characterological self-blaming attributions for harassment than behavioral self-blaming attributions. Characterological self-blame, in turn, partly mediated the relationship between victim status and psychological maladjustment as measured by depression and social anxiety. Many studies since then have documented the relation between being targets of bullying, characterological self-blame, and maladjustment ( Graham et al., 2006 , 2009 ; Perren et al., 2012 ; Prinstein et al., 2005 ). Furthermore, bullied youth who endorsed characterological self-blame were likely to develop negative expectations about the future, which may also increase risk for continued bullying. For example, Schacter and colleagues (2014) reported that characterological self-blame endorsed in the fall of sixth grade predicted increases in reports of being bullied in the spring of sixth grade. Self-blame can then instigate psychological distress over time as well as increases in experiences of being bullied.

Such findings have implications for interventions targeted at bullied youth. The goal would be to change targets' maladaptive thoughts about the causes of their plight. For example, one could seek more adaptive attributions that could replace characterological self-blame. In some cases, change efforts might target behavioral explanations for being bullied (e.g., “I was in the wrong place at the wrong time”). In such cases, the goal would be to help targeted youth recognize that they have responses in their repertoire to prevent future encounters with harassing peers—that is, the cause is unstable and controllable ( Graham and Bellmore, 2007 ). External attributions also can be adaptive because they protect self-esteem ( Weiner, 1986 ). Knowing that others are also victims or that there are some aggressive youth who randomly single out unsuspecting targets can help lessen the tendency to self-blame ( Graham and Bellmore, 2007 ; Nishina and Juvonen, 2005 ). This approach of altering dysfunctional thoughts about oneself to produce changes in affect and behavior has produced a rich empirical literature on attribution therapy in educational and clinical settings (see Wilson et al., 2002 ). The guiding assumption of that research can be applied to alleviating the plight of targets of bullying.

Social Cognition

The most commonly cited models of social cognitive processes often connect back to work by Bandura (1973) , as well as to more recent conceptualizations by Crick and Dodge (1994) . These models have been applied to understanding aggressive behavior, but there has been less research applying these models to bullying behavior specifically. Related research by Anderson and Bushman (2002) on their general aggression model allows for a more focused understanding of the thoughts, feelings, and behaviors that contribute to the development of the negative outcome. This framework characterizes the inputs, the routes, the proximal processes, and the outcomes associated with aggressive behavior and either being targeted by or perpetrating bullying behavior ( Kowalski and Limber, 2013 ; Vannucci et al., 2012 ). Although these theories pertain to aggressive behavior more broadly, given that bullying is considered by most researchers to be a specific form of aggressive behavior, these broader theories may also improve understanding of the etiology and development of bullying. For example, research on hostile attribution bias suggests that aggressive youth are particularly sensitive to ambiguous and potentially hostile peer behaviors. Similar hypersensitivity to threat is also likely present in youth who bully.

Another particular element of social cognitive processes that has been linked with aggressive behavior is normative beliefs about aggressive retaliation ( Crick and Dodge, 1994 ; Huesmann and Guerra, 1997 ). Such beliefs include the belief that aggressive retaliation is normative, acceptable, or justified, given the context of provocation. There has been exploration of links between these beliefs and both reactive and proactive aggression. However, there has been relatively limited research specifically focused on bullying behavior. Yet, the available literature suggests that although it may seem as if targets of bullying would most likely endorse such attitudes, it is the perpetrators of bullying, including those who are involved in bullying as both a perpetrator and a target, who are mostly likely to support aggressive retaliation ( Bradshaw et al., 2009 , 2013 ; O'Brennan et al., 2009 ).

Emotion Dysregulation

Attempts to identify mechanisms linking bullying to adverse outcomes have largely focused on social-cognitive processes ( Dodge et al., 1990 ) as described above. More recently, researchers have begun to examine emotion dysregulation as an additional mechanism that explains associations between peer victimization and adverse outcomes. Emotion regulation refers to the strategies that people use to “increase, maintain, or decrease one or more components of an emotional response” ( Gross, 2001 , p. 215). One's choices among such strategies have implications not only for how robustly one responds to a stressor but also for how quickly one can recover from a stressful experience. Several studies have shown that emotion regulation difficulties—also called emotion dysregulation —increase youths' risk of exposure to peer victimization ( Hanish et al., 2004 14 ) and to bullying ( Mahady Wilton et al., 2000 ). However, it is important to understand whether peer victimization itself causes emotion regulation difficulties, which in turn predict the adverse outcomes that result from peer victimization (e.g., depression, aggressive behaviors).

Several lines of evidence support the hypothesis that emotion dysregulation may account for the relationship between peer victimization and adverse outcomes among adolescents. First, constructs that are related to peer victimization—including social exclusion ( Baumeister et al., 2005 ) and stigma ( Inzlicht et al., 2006 )—impair self-regulation. Second, chronic stress during childhood and adolescence leads to deficits in emotion regulation ( Repetti et al., 2002 ). Bullying has been conceptualized as a chronic stressor for children who are the perpetrators and the targets ( Swearer and Hymel, 2015 ), which in turn may disrupt emotion regulation processes. Third, laboratory-based studies have indicated that peer victimization is associated with emotion dysregulation (e.g., self-directed negative emotion, emotional arousal and reactivity) in the context of a novel peer interaction ( Rudolph et al., 2009 ) and in a contrived play-group procedure ( Schwartz et al., 1993 ). Over time, the effort required to manage the increased arousal and negative affect associated with peer victimization 15 may eventually diminish individuals' coping resources and therefore their ability to understand and adaptively manage their emotions, leaving them more vulnerable to adverse outcomes ( McLaughlin et al., 2009 ).

Several studies have provided empirical support for emotion dysregulation as a mediator of the association between peer victimization and adverse outcomes among adolescents. In one of the first longitudinal demonstrations of mediation, McLaughlin and colleagues (2009) , using data from a large, prospective study of adolescents (ages 11-14), showed that peer victimization at baseline predicted increases in emotion dysregulation four months later, controlling for initial levels of emotion dysregulation. In turn, emotion dysregulation predicted subsequent psychological distress (depressive and anxious symptoms), thereby mediating the prospective relationship between peer victimization (relational and reputational forms) and internalizing symptoms ( McLaughlin et al., 2009 ). Subsequent research from this same sample of adolescents showed that emotion dysregulation also mediated the prospective relationship between peer victimization and subsequent aggressive behavior ( Herts et al., 2012 ).

There is also emerging evidence that emotion regulation mediates relationships between bullying and adverse outcomes. In one example of this work, Cosma et al. (2012) examined associations between bullying and several emotion regulation strategies, including rumination, catastrophizing, and other-blaming, in a sample of adolescents. Although bullying was predictive for each of these emotion regulation strategies, only one (catastrophizing) mediated the relationship between being a target of bullying and subsequent emotional problems. Thus, while more research is needed, existing evidence suggests that both social-cognitive and emotion regulation processes may be important targets for preventive interventions among youths exposed to peer victimization and bullying.

Genetic Predisposition to Mental Health Outcomes and Bullying

Longitudinal research suggests that being the victim or perpetrator of bullying does not lead to the same pathological or nonpathological outcomes in every person ( McDougall and Vaillancourt, 2015 ). There are many factors that contribute to how a person responds to the experience of being victimized, with very strong links already established with life experiences, as reviewed above. Most studies examining heterogeneity in outcomes associated with bullying have focused on environmental characteristics, such as individual, family, and school-level features to explain why some individuals fare better or worse when involved with bullying ( Vaillancourt et al., in press ). For example, the moderating role of the family has been examined with results indicating that bullied children and youth with better home environments tend to fare better than those living with more complicated families ( Flouri and Buchanan, 2003 ; also see Chapter 3 of this report). Far fewer studies have examined the role of potential genetic influences as mediators between life experiences such as bullying and mental health outcomes. Identifying potential genetic influences is critical for improving understanding of the rich behavioral and epidemiological data already gathered. At the present time, evidence-based understanding of physiology and neuroscience is very limited, and insufficient data have been gathered to produce informed hypothesis testing.

There is a growing body of literature examining the relative role of genes' interaction with the environment in relation to experiences with trauma. However, there are fewer studies exploring potential relations between genes and being the target or perpetrator of bullying. At first glance these studies may appear to suggest that a person's involvement with bullying is predetermined based on his/her genetic profile. Yet, it is important to bear in mind that heritable factors are also associated with specific environments—meaning it is difficult to separate genetic effects from environmental effects. This is a phenomenon termed gene-environment correlations , abbreviated as rGE ( Brendgen, 2012 ; Plomin et al., 1977 ; Scarr and McCartney, 1983 ). For example, aggression, which is highly heritable ( Niv et al., 2013 ), can be linked to the selection of environments in different ways (for review, see Brendgen, 2012 ). Aggressive children may choose friends who are similar in their genetically influenced behavioral characteristic of being aggressive, and this type of selection influences the characteristics of their peer group ( Brendgen, 2012 , p. 420). This is an example of selective rGE. A child's genetically influenced characteristic to be aggressive can also produce a negative reaction from others, such as being disliked. This environmental variable of being rejected now “becomes correlated with the aggressive genotype” ( Brendgen, 2012 , p. 421). This is an example of evocative rGE. Another way that a person's genetic predisposition can be correlated with their environment is through a more passive process, called a passive rGE ( Brendgen, 2012 ). For example, aggressive parents may be more likely to live in high-crime neighborhoods, which influence the probability that their child will be associating with antisocial peers. These important rGE processes and confounds of interaction notwithstanding, it is worth mentioning that the research on the genetics of being a target or perpetrator of bullying is still in its infancy, and caution is needed when evaluating the results, as replication is much needed in this area. Before considering these studies, the committee first reviews the concept of how genetic differences influence behavior because it is important to clarify new concepts in this burgeoning area of science (see Box 4-3 ).

How Do Genes Influence Behavior?

With this backdrop in mind, the committee focused on twin studies of familial (family environment) versus genetic influence, gene by environment interaction, and a newer area of inquiry, epigenetics: the study of cellular and physiological phenotypic trait variations caused by external or environmental factors.

Twin Studies

Twin studies are routinely used to examine the relative influence of genetics and the environment on a particular phenomenon, such as being the target or perpetrator of bullying. In these studies, the causes of phenotypic variation (for example the variation in being a target or perpetrator of bullying) is separated into three components: (1) the additive genetic component or the heritable factor; (2) the shared environment component or the aspect of the environment twins share such as poor family functioning; and (3) the nonshared environment component or the aspect of the environment that is unique to each twin, such as the classroom if twins are in different classes.

Studies that decompose the unique effects of the environment and genetics on bullying behavior are best illustrated by two examples. Using data from the Environmental Risk (E-Risk) Longitudinal Twin Study, a study of high-risk 16 British twins reared together and apart, Ball and colleagues (2008) examined children's involvement in bullying and the genetic versus environmental contributions associated with their involvement. The twins in this study were assessed at ages 7 and 10 on their experiences with bullying, using teacher and parent reports. Results indicated that 73 percent of the variation in being the target of bullying and 61 percent of the variation in bullying perpetration were accounted for by genetic factors. In another study of Canadian twins reared together and assessed at age 7, using teacher and peer reports to assess peer victimization and aggression, Brendgen and colleagues (2008) found that for girls, 60 percent of the variation in aggression was accounted for by genetic factors and for boys, the variation estimate was 66 percent. For peer victimization, the Canadian study found that genetics did not play a role in the prediction of being targeted by peers. In fact, almost all of the variance was accounted for by environmental factors—29 percent of the variance in peer victimization was from the shared environment and 71 percent from the nonshared environment. The authors concluded that “genetic modeling showed that peer victimization is an environmentally driven variable that is unrelated to children's genetic disposition” ( Brendgen et al., 2008 , p. 455).

These two studies address the role genetics might play in the expression of aggressive behavior but conflict on the heritability of being a target of bullying. Most studies examining the heritability of externalizing problems, which includes studies on perpetrating aggression and bullying, report high heritability estimates. In fact, a recent meta-analysis found that aggression and rule-breaking were highly influenced by genetics, estimating the heritability rate at 41 percent ( Niv et al., 2013 ). Moreover, studies have found that the heritability estimates tend to be higher for more serious forms of antisocial behavior. For example, the heritability of psychopathy in 7-year-old British twin children reared together and apart and studied in the Twins Early Development Study was reported to be 81 percent ( Viding et al., 2005 ). However, estimates of the heritability of peer victimization vary across studies, as illustrated by the above results from Ball and colleagues (2008) contrasted with those from Brendgen and colleagues (2008) , and even within studies ( Brendgen et al., 2008 , 2013 ).

Brendgen and colleagues have since revised their assessment about the role genetics play in the prediction of being the target of bullying. In a more recent study, following the same children highlighted in the 2008 paper ( Brendgen et al., 2008 ) across three assessment periods (kindergarten, grade 1, and grade 4), Boivin and colleagues (2013) reported that at each grade, among twins who were reared together and apart, genetic factors accounted for a notable percentage of the variance in children's difficulties with peers. Peer difficulties were assessed as a latent factor derived from self-, teacher-, and peer-reports of peer victimization 17 and peer rejection. Specifically, in kindergarten and grade 1, 73 percent of the variance was accounted by genetic factors and in grade 4, genetic factors account for 94 percent of the variance in peer rejection and victimization.

There are several reasons for discrepancies between and within studies of the genetic contribution to bullying behavior. One reason is related to how peer victimization is assessed. Parent-, teacher-, peer-, and self-reports of bullying victimization have been shown to vary considerably across reporters ( Ostrov and Kamper, 2015 ; Patton et al., 2015 ; Shakoor et al., 2011 ); thus, the method used to assess involvement with bullying may lead to different results. Another reason for the differences may be related to development. The influence of the environment is expected to change as children age. Young children are particularly sensitive to family influences, while the influence of peers tends to matter more during adolescence ( Harris, 1995 ). Moreover, the type of environment a person is exposed to (i.e., harsh or nurturing) interacts with genes to produce a brain that is tailored to deal with the particular demands of that environment.

Taken together, the genetic studies reviewed suggest that aggression, which characterizes the perpetrator role in bullying ( Vaillancourt et al., 2008 ), might have heritable components, but the findings on being the target of bullying or other aggressive behavior are mixed. Thus, the role of genetic influences on both perpetrating and being a target of bullying requires more empirical attention before conclusions can be drawn.

Gene-by-Environment Interactions

Researchers also question whether specific genotypic markers of vulnerability (e.g., candidate genes) influence developmental outcomes in the face of adversity (i.e., environment). Importantly, there is some indication that genetics influences the mental health issues related to bullying highlighted above, such as depression and heightened aggression. For example, in gene-environment studies, candidate genes have been examined as moderators of the exposure to a toxic stressor such as child maltreatment and health outcomes such as depression. When the body experiences repeated bouts of stress that fail to resolve quickly, the heightened state of vigilance and preparedness depletes it of resources and the stress hormone cortisol begins to produce adverse effects. Specifically, prolonged stress disrupts brain functions and results in compromised decision making, faulty cognitive assessment, compromised learning and memory, and a heightened sense of threat that alters behavior ( Lupien et al., 2005 ; McEwen, 2014 ). There is evidence that the impact of changes in cortisol (either too high or too low) on learning may contribute, in part, to bullied children's decline in academic performance ( Vaillancourt et al., 2011 ), overeating/metabolic disorder, or emotional dysregulation, but this research is relatively new and needs to be explicitly explored within the context of bullying ( McEwen, 2014 ).

A paradigmatic example of this type of study is one by Caspi and colleagues (2003) , in which the moderating role of a functional polymorphism in the promoter region of the serotonin transporter gene 5-HTTLPR was examined in relation to exposure to maltreatment in childhood and depression in adulthood. Results indicated that depression rates were far greater among abused individuals if they had two copies of the short allele. 18 Among individuals with a long allele, depression rates were lower, suggesting that the long allele was protective, while the short allele was a risk factor for depression in the face of adversity. Although the exact role of this serotonin-related gene has been a subject of controversy, a meta-analysis concluded that overall, the results are consistent across studies ( Karg et al., 2011 ). Nevertheless, skepticism and controversy remain regarding studies of gene-environment interactions ( Dick et al., 2015 ; Duncan, 2013 ; Duncan and Keller, 2011 ; Duncan et al., 2014 ). This important debate notwithstanding, there is evidence that variations in genotype might moderate the relation between exposure to being bullied and health outcomes. For example, Sugden and colleagues (2010) found that bullied children who carried two short versions of the 5-HTTLPR gene were more likely to develop emotional problems than bullied children who carried the long allele. Importantly, this moderating effect was present even when pre-victimization emotional problems were accounted for statistically. In addition to this study, three other studies have demonstrated the moderating effect of the 5-HTTLPR gene in the bullying-health link ( Banny et al., 2013 ; Benjet et al., 2010 ; Iyer et al., 2013 ), with depression being worse for carriers of the short/short genotype (both alleles are the short version) than carriers of the short/long and long/long genotypes.

Although the evidence suggests that genotypes moderate the relation between being a target of bullying and poorer mental health functioning like depression, it is important to acknowledge that this relation is more complex. Indeed, some individuals may be particularly biologically sensitive to negative environmental influences such as being bullied, but this genetic vulnerability can also be linked to better outcomes in the context of a more supportive and enriched environment (see Vaillancourt et al., in press ). This phenomenon is termed differential susceptibility ( Belsky and Pluess, 2009 ; Boyce and Ellis, 2005 ). For example, in their study of 5 and 6-year old children, Obradovic and colleagues (2010) found that high stress reactivity as measured using respiratory sinus arrhythmia and salivary cortisol was linked to poorer socioemotional behavior in the context of being in an environment that was high in family adversity. In a context characterized by lower adversity, high stress-reactive children had more adaptive outcomes.

To the committee's knowledge, there are no studies that have examined bullying perpetration in relation to serotonin transporter polymorphisms, although there are studies that have examined this polymorphism in aggressive and non-aggressive children. For example, Beitchman et al. (2006) examined 5-HTTLPR in clinically referred children between the ages of 5 and 15 and found a positive association between the short/short genotype and aggression. In other studies, the short allele has been associated with problems with impulse control that includes the use of aggression ( Retz et al., 2004 ).

The moderating role of different candidate genes has also been examined in relation to exposure to childhood adversity and poorer developmental outcomes (see review by Vaillancourt et al., in press ). With respect to bullying, only a few studies have examined gene-environment interactions. In one study by Whelan and colleagues (2014) , harsh parenting was associated with increased peer victimization and perpetration, but this effect was not moderated by the Monoamine Oxidase A (MAOA) genotype. 19 In another longitudinal study, Kretschmer and colleagues (2013) found that carriers of the 4-repeat homozygous variant of the dopamine receptor D4 gene were more susceptible to the effects of peer victimization 20 on delinquency later in adolescence than noncarriers of this allele. Finally, in a large sample of post-institutionalized children from 25 countries, VanZomeren-Dohm and colleagues (2015) examined the moderating role of FKBP5 rs1360780 21 in the relation between peer victimization 22 and depression symptoms. In this study, gender was also found to be a moderator. Specifically, girls who had the minor genotype (TT or CT) were more depressed at higher levels of peer victimization, but less depressed at lower level of peer victimization than girls who had CC genotype. For boys, the CC genotype was associated with more symptoms of depression than girls with the same CC genotype who had been bullied.

It is clear that genetics influences how experiences contribute to mental and physical well-being, although the specifics of these gene-environment interactions are complex and not completely understood. Even though genes appear to modulate humans' response to being a target or a perpetrator of bullying behavior, it is still unclear what aspects of these experiences are interacting with genes and which genes are implicated to produce the variability in outcomes. Human genes and environment interact in a very complex manner: what biological events a particular gene influences can change at different stages of development. That gene therefore interacts with the environment in unique ways across the development timeline. These gene-environment interactions can be subtle and are under constant flux ( Lake and Chan, 2015 ). Knowing both the genes involved and the specific environment conditions is critically important to understanding these interactions; a simplistic view of either the genetic or environmental component, especially when considered in isolation from the behavioral literature, is unlikely to be productive.

Epigenetic Consequences

It is clear from the research reviewed here that there are a variety of pathways leading to adaptive and maladaptive endpoints and that these pathways can also vary within the “system” along with other conditions and attributes ( McDougall and Vaillancourt, 2015 , p. 300), including a person's genetic susceptibility. In this section, the committee focuses on studies examining how genetic susceptibility can make certain individuals more sensitive to negative environmental influences.

Although a person's DNA is fixed at conception (i.e., nonmalleable), environment can have a strong effect on how some genes are used at each of the stages of development. One way such changes in gene use and expression can occur is through an epigenetic effect, in which environmental events alter the portions of the genome that control when gene replication is turned on or off and what parts of a gene get transcribed ( McGowan et al., 2009 ; Roth, 2014 ). That is, while an individual's genetic information is critically important, the environment can help to increase or decrease how some genetic information is used by indirectly turning on or off some genes based on input received by somatic cells from the environment. Such epigenetic alterations have been empirically validated in several animal studies. For example, in one line of epigenetic studies, infant rat pups are raised with either low- or high-nurturing mothers or with mothers that treated the pups harshly. The researchers found that the type of maternal care received in infancy had a notable effect on the rats' subsequent ability to deal with stress ( McGowan et al., 2011 ; Roth and Sweatt, 2011 ; Weaver et al., 2004 ). The behavioral effects were correlated with changes in DNA methylation. 23 Epigenetic changes associated with gene-environment interactions is a new and exciting research area that provide a direct link between how our genes are read and is thought to enable us to pass our experiences to the next generations. It is helpful to think of genes as books in a library and epigenetics as placing a barrier in front of a book to decrease the chances it is read or providing easy access to the book. Thus far, research has found that certain epigenetic mechanisms are strongly correlated with different neurobehavioral developmental trajectories, including changes in vulnerability and resilience to psychopathology. How epigenetics relates to individual responses to being a target or perpetrator of bullying is not clear, but the research in related areas of behavior highlights an important emerging area for investigation.

Various epigenetic processes appear to interact with many changes in the brain produced by early life experiences, including not only the number and shape of brain cells but also how these cells connect to one another at synapses ( Hanson et al., 2015 ).

Regarding bullying, the committee identified only one study that has examined epigenetic changes. Specifically, Ouellet-Morin and colleagues (2013) found an increase in DNA methylation of the serotonin transporter gene for children who had been bullied by their peers but not in children who had not been bullied. These researchers also found that children with higher serotonin DNA methylation had a blunted cortisol response to stress, which they had previously shown changes as a consequence of poor treatment by peers ( Ouellet-Morin et al., 2011 ). That is, their 2011 study of twin children assessed at ages 5 and 10 found that being bullied was correlated with a change in how the body responds to stress. Bullied children displayed a blunted cortisol response to a psychosocial stress test. Because the design of the study involved an examination of identical twins who were discordant with respect to their experiences of being bullied (one twin was bullied while the other one was not), Ouellet-Morin and colleagues (2011) concluded that the effect could not be attributed to “variations in either genetic makeup, family environment, or other concomitant factors, nor could they be attributed to the twins' perceptions of the degree of stress experienced during the task” ( Vaillancourt et al., 2013a , p. 243).

In summary, it is important to note that there is no gene for being a perpetrator or a target of bullying behavior. Based on current knowledge of the genetics of complex social behavior, such as bullying, the genetic component of individual response is likely to involve multiple genes that interact with the environment in a complex manner. The current understanding of genetics and complex behaviors is that genes do not cause a behavior; gene-by-environment studies do not use the word “environment” the same way it is used in everyday language or even in traditional social psychology (as in Chapter 3 ). Rather, it is a construct used in a model to estimate how much variability exists in a given environment. This means that the same gene placed in different environments would yield very different percentages for gene-environment interactions. It is unclear how this information would inform our understanding of bullying.

Telomere Erosion Consequences

Epigenetic research has found that negative life experiences can alter the expression of a gene, which in turn, can confer a risk for poor outcomes. Research also suggests that the experience of being bullied is associated with telomere erosion. The end of each chromatid has been found to shorten as people age; this telomere “tail” also erodes as a function of engaging in unhealthy behavior such as smoking or being obese. Telomere erosion is also associated with certain illnesses such as cancer, diabetes, and heart disease ( Blackburn and Epel, 2012 ; Kiecolt-Glaser et al., 2011 ; Vaillancourt et al., 2013a ). Given these associations, scientists are now examining telomere erosion as a biomarker of stress exposure ( Epel et al., 2004 ), including the stress of being bullied by peers.

A recent longitudinal study by Shalev and colleagues (2013) examined telomere erosion in relation to children's exposure to violence, 24 a significant early-life stressor that is known to have long-term consequences for health. They found that exposure to violence, including being a target of bullying, was associated with telomere erosion for children assessed at age 5 and again at age 10. The sample for this study included 236 children recruited from the Environmental-Risk Longitudinal Twin Study ( Moffitt, 2002 ), 42 percent of whom had one or more exposures to violence. The study found that cumulative exposure to violence 25 is positively associated with accelerated telomere erosion in children, from baseline to follow-up, with potential impact for life-long health ( Shalev et al., 2013 ).

In this chapter, the committee reviewed and critically analyzed the available research on the physical health, psychosocial, and academic achievement consequences for children and youth who are bullied, for those who bully, for those who are both bullied and bullies, and for those who are bystanders to events of bullying. It also examined the potential mediating mechanisms of, and the genetic predisposition to, mental health outcomes associated with childhood and youth experiences of bullying behavior. Most studies are cross-sectional and thus provide only associations suggestive of a possible causal effect. This problem is most acute for studies based on anonymous self-report, in which both the independent variable (experience of bullying in one or more roles) and dependent variables (such as emotional adjustment) are data collected at the same time from sources subject to various forms of bias.

The limited amount of data from longitudinal and experimental research designs limits the ability to draw conclusions with respect to causality. Additional longitudinal studies, for example, could help establish that the negative consequences attributed to bullying were not present before the bullying occurred. But even this does not prove a causal effect, since bullying and the associated impairments might be products of some third factor. Below, the committee summarizes what is known about associations and consequences and identifies key conclusions that can be drawn from this evidence base.

• FINDINGS AND CONCLUSIONS

Finding 4.1: Individuals who both bully and are also bullied by others experience a greater variety of both internalizing and externalizing symptoms than those who only bully or are only bullied. Finding 4.2: Individuals who bully others are likely to experience negative emotional, behavioral, and mental health outcomes, though most research has not distinguished perpetration of bullying from other forms of peer aggression. Finding 4.3: A large body of research indicates that individuals who have been bullied are at increased risk of subsequent mental, emotional, and behavioral problems, especially internalizing problems. Finding 4.4: Studies of bystander behavior in bullying have rarely examined the emotional and psychological impact of witnessing bullying. Finding 4.5: Children and youth who are bullied subsequently experience a range of somatic disturbances. Finding 4.6: Social-cognitive factors (e.g., self-blame) and unsuccessful emotion regulation (i.e., emotion dysregulation) mediate relationships between bullying and adverse outcomes. Finding 4.7: There is evidence that stressful events, such as might occur with experiences of being bullied, alter emotional brain circuits. This potential outcome is critically in need of further investigation. Finding 4.8: Genetics influences how experiences contribute to mental and physical well-being, although the nature of this relationship is complex and not completely understood. Finding 4.9: Emerging evidence suggests that repeated exposure to bullying may produce a neural signature that could underlie some of the behavioral outcomes associated with being bullied. Finding 4.10: There are limited data on the physical health consequence of bullying for those individuals who are involved in bullying as targets, perpetrators, as both targets and perpetrators, and as bystanders. Finding 4.11: Poly-victims (individuals who are targets of multiple types of aggression) are more likely to experience negative emotional, behavioral, and mental health outcomes than individuals targeted with only one form of aggression. Finding 4.12: The long-term consequences of being bullied extend into adulthood and the effects can be more severe than other forms of being maltreated as a child. Finding 4.13: Individuals who are involved in bullying (as perpetrators, targets, or both) in any capacity are significantly more likely to contemplate or attempt suicide, compared to children who are not involved in bullying. It is not known whether bystanders are at increased risk of suicidal ideation or suicide attempts. Finding 4.14: There is not enough evidence to date to conclude that being the target of bullying is a causal factor for multiple-homicide targeted school shootings, nor is there clear evidence on how experience as a target or perpetrator of bullying, or the mental health and behavior issues related to such experiences, contribute to school shootings.

Conclusions

Conclusion 4.1: Further research is needed to obtain more in-depth evidence on the physical health consequences of being the target of bullying including neural consequences. Conclusion 4.2: Additional research is needed to examine mediators of short- and long-term physical health outcomes of individuals who are bullied. Evidence is also needed regarding how these outcomes vary over time for different groups of children and youth, why individuals with similar experiences of being bullied might have different physical health outcomes, and how physical and emotional health outcomes intersect over time. Conclusion 4.3: Although the effects of being bullied on the brain are not yet fully understood, there are changes in the stress response systems and in the brain that are associated with increased risk for mental health problems, cognitive function, self-regulation, and other physical health problems. Conclusion 4.4: Bullying has significant short- and long-term internalizing and externalizing psychological consequences for the children who are involved in bullying behavior. Conclusion 4.5: The data are unclear on the role of bullying as one of or a precipitating cause of school shootings. Conclusion 4.6: Individuals who both bully others and are themselves bullied appear to be at greatest risk for poor psychosocial outcomes, compared to those who only bully or are only bullied and to those who are not bullied. Conclusion 4.7: While cross-sectional studies indicate that children who are bullied are at increased risk for poor academic achievement relative to those who are not bullied, the results from longitudinal studies are inconsistent and warrant more research. Conclusion 4.8: Existing evidence suggests that both social-cognitive and emotion regulation processes may mediate the relation between being bullied and adverse mental health outcomes. Conclusion 4.9: Although genes appear to modulate humans' response to being either a target or a perpetrator of bullying behavior, it is still unclear what aspects of these experiences are interacting with genes and which genes are implicated to produce the variability in outcomes. Examining the role of genes in bullying in the context of the environment is essential to providing meaningful information on the genetic component of individual differences in outcomes from being a target or a perpetrator of bullying behavior.

• Anderson CA, Bushman BJ. Human aggression. Annual Review of Psychology. 2002; 53 (1):27–51. [ PubMed : 11752478 ]
• Anderson CA, Miller RS, Riger AL, Dill JC, Sedikides C. Behavioral and characterological attributional styles as predictors of depression and loneliness: Review, refinement, and test. Journal of Personality and Social Psychology. 1994; 66 (3):549–558. [ PubMed : 8169764 ]
• Archer J. Testosterone and human aggression: An evaluation of the challenge hypothesis. Neuroscience and Biobehavioral Reviews. 2004; 30 (3):319–345. [ PubMed : 16483890 ]
• Arseneault L, Walsh E, Trzesniewski K, Newcombe R, Caspi A, Moffitt T. Bullying victimization uniquely contributes to adjustment problems in young children: A nationally representative cohort study. Pediatrics. 2006; 118 (1):130–138. [ PubMed : 16818558 ]
• Baldwin J, Arseneault L, Danese A. Childhood bullying and adiposity in young adulthood: Findings from the E-Risk Longitudinal Twin Study. Psychoneuroendocrinology. 2015; 61 :16.
• Ball HA, Arseneault L, Taylor A, Maughan B, Caspi A, Moffitt TE. Genetic and environmental influences on victims, bullies and bully-victims in childhood. Journal of Child Psychology and Psychiatry. 2008; 49 (1):104–112. [ PubMed : 18181884 ]
• Baly MW, Cornell DG, Lovegrove P. A longitudinal investigation of self- and peer reports of bullying victimization across middle school. Psychology in the Schools. 2014; 51 (3):217–240.
• Bandura A. Aggression: A Social Learning Analysis. Englewood Cliffes, NJ: Prentice-Hall; 1973.
• Banny AM, Cicchetti D, Rogosch FA, Oshri A, Crick NR. Vulnerability to depression: A moderated mediation model of the roles of child maltreatment, peer victimization, and serotonin transporter linked polymorphic region genetic variation among children from low socioeconomic status backgrounds. Development and Psychopathology. 2013; 25 (03):599–614. [ PMC free article : PMC3959105 ] [ PubMed : 23880379 ]
• Baratta MV, Kodandaramaiah SB, Monahan PE, Yao J, Weber MD, Lin PA, Gisabella B, Petrossian N, Amat J, Kim K. Stress enables reinforcement-elicited serotonergic consolidation of fear memory. Biological Psychiatry. 2015; 79 (10):814–822. [ PMC free article : PMC4698247 ] [ PubMed : 26248536 ]
• Barnes DC, Wilson DA. Slow-wave sleep-imposed replay modulates both strength and precision of memory. Journal of Neuroscience. 2014; 34 (15):5134–5142. [ PMC free article : PMC3983797 ] [ PubMed : 24719093 ]
• Barra CB, Silva IN, Rodrigues TMB, Santos JLS, Colosimo EA. Morning serum basal cortisol levels are affected by age and pubertal maturation in school-aged children and adolescents. Hormone Research in Paediatrics. 2015; 83 (1):55–61. [ PubMed : 25592297 ]
• Baumeister RF, DeWall CN, Ciarocco NJ, Twenge JM. Social exclusion impairs self-regulation. Journal of Personality and Social Psychology. 2005; 88 (4):589–604. [ PubMed : 15796662 ]
• Beitchman JH, Baldassarra L, Mik H, Hons B, Vincenzo De Luca M, King N, Bender D, Ehtesham S, Kennedy JL. Serotonin transporter polymorphisms and persistent, pervasive childhood aggression. American Journal of Psychiatry. 2006; 163 (6):1103–1105. [ PubMed : 16741214 ]
• Belsky J, Pluess M. Beyond diathesis stress: Differential susceptibility to environmental influences. Psychological Bulletin. 2009; 135 (6):885–908. [ PubMed : 19883141 ]
• Belujon P, Grace AA. Regulation of dopamine system responsivity and its adaptive and pathological response to stress. Proceedings of the Royal Society of London B: Biological Sciences. 2015; 282 (1805):1–10. [ PMC free article : PMC4389605 ] [ PubMed : 25788601 ]
• Benjet C, Thompson RJ, Gotlib IH. 5-HTTLPR moderates the effect of relational peer victimization on depressive symptoms in adolescent girls. Journal of Child Psychology and Psychiatry. 2010; 51 (2):173–179. [ PMC free article : PMC2804775 ] [ PubMed : 19754661 ]
• Beran T. Correlates of peer victimization and achievement: An exploratory model. Psychology in the Schools. 2009; 46 (4):348–361.
• Beran TN, Lupart J. The relationship between school achievement and peer harassment in Canadian adolescents: The importance of mediating factors. School Psychology International. 2009; 30 (1):75–91.
• Beran TN, Hughes G, Lupart J. A model of achievement and bullying: Analyses of the Canadian National Longitudinal Survey of Children and Youth data. Educational Research. 2008; 50 (1):25–39.
• Blackburn EH, Epel ES. Nature. 7419. Vol. 490. 2012. pp. 169–171. [ PubMed : 23060172 ]
• Blakemore SJ. Development of the social brain in adolescence. Journal of the Royal Society of Medicine. 2012; 105 (3):111–116. [ PMC free article : PMC3308644 ] [ PubMed : 22434810 ]
• Boden JM, van Stockum S, Horwood LJ, Fergusson DM. Bullying victimization in adolescence and psychotic symptomatology in adulthood: Evidence from a 35-year study. Psychological Medicine. 2016; 46 (6):1311–1320. [ PubMed : 26804185 ]
• Bogart LM, Elliott MN, Klein DJ, Tortolero SR, Mrug S, Peskin MF, Davies SL, Schink ET, Schuster MA. Peer victimization in fifth grade and health in tenth grade. Pediatrics. 2014; 133 (3):440–447. [ PMC free article : PMC4530298 ] [ PubMed : 24534401 ]
• Boivin M, Brendgen M, Vitaro F, Dionne G, Girard A, Perusse D, Tremblay RE. Strong genetic contribution to peer relationship difficulties at school entry: Findings from a longitudinal twin study. Child Development. 2013; 84 (3):1098–1114. [ PubMed : 23210840 ]
• Booth A, Granger DA, Shirtcliff EA. Gender- and age-related differences in the association between social relationship quality and trait levels of salivary cortisol. Journal of Research on Adolescence. 2008; 18 (2):239–260.
• Borum R, Cornell DG, Modzeleski W, Jimerson SR. What can be done about school shootings? A review of the evidence. Educational Researcher. 2010; 39 (1):27–37.
• Bowes L, Joinson C, Wolke D, Lewis G. Peer victimisation during adolescence and its impact on depression in early adulthood: Prospective cohort study in the United Kingdom. The BMJ. 2015; 350 :1–9. [ PMC free article : PMC4452929 ] [ PubMed : 26037951 ]
• Boyce WT, Ellis BJ. Biological sensitivity to context: I. An evolutionary-developmental theory of the origins and functions of stress reactivity. Development and Psychopathology. 2005; 17 (2):271–301. [ PubMed : 16761546 ]
• Bradshaw CP, Sawyer AL, O'Brennan LM. A social disorganization perspective on bullying-related attitudes and behaviors: The influence of school context. American Journal of Community Psychology. 2009; 43 (3-4):204–220. [ PubMed : 19333749 ]
• Bradshaw CP, Goldweber A, Fishbein D, Greenberg MT. Infusing developmental neuroscience into school-based preventive interventions: Implications and future directions. Journal of Adolescent Health. 2012; 51 (2):S41–S47. [ PubMed : 22794533 ]
• Brendgen M. Genetics and peer relations: A review. Journal of Research on Adolescence. 2012; 22 (3):419–437.
• Bradshaw CP, Goldweber A, Garbarino J. Linking social-environmental risk factors with aggression in suburban adolescents: The role of social-cognitive mediators. Psychology in Schools. 2013; 50 (5):433–450.
• Brendgen M, Boivin M, Vitaro F, Bukowski WM, Dionne G, Tremblay RE, Pérusse D. Linkages between children's and their friends' social and physical aggression: Evidence for a gene–environment interaction? Child Development. 2008; 79 (1):13–29. [ PubMed : 18269506 ]
• Brendgen M, Girard A, Vitaro F, Dionne G, Boivin M. Do peer group norms moderate the expression of genetic risk for aggression? Journal of Criminal Justice. 2013; 41 (5):324–330.
• Buhs ES, Ladd GW, Herald SL. Peer exclusion and victimization: Processes that mediate the relation between peer group rejection and children's classroom engagement and achievement? Journal of Educational Psychology. 2006; 98 (1):1–13.
• Camodeca M, Goossens FA, Schuengel C, Terwogt MM. Links between social information processing in middle childhood and involvement in bullying. Aggressive Behavior. 2003; 29 (2):116–127.
• Casement MD, Guyer AE, Hipwell AE, McAloon RL, Hoffmann AM, Keenan KE, Forbes EE. Girls' challenging social experiences in early adolescence predict neural response to rewards and depressive symptoms. Developmental Cognitive Neuroscience. 2014; 8 :18–27. [ PMC free article : PMC3960334 ] [ PubMed : 24397999 ]
• Casey B, Jones RM. Neurobiology of the adolescent brain and behavior: Implications for substance use disorders. Journal of the American Academy of Child & Adolescent Psychiatry. 2010; 49 (12):1189–1201. [ PMC free article : PMC3099425 ] [ PubMed : 21093769 ]
• Caspi A, Sugden K, Moffitt TE, Taylor A, Craig IW, Harrington H, McClay J, Mill J, Martin J, Braithwaite A. Influence of life stress on depression: Moderation by a polymorphism in the 5-HTT gene. Science. 2003; 301 (5631):386–389. [ PubMed : 12869766 ]
• Chattarji S, Tomar A, Suvrathan A, Ghosh S, Rahman MM. Neighborhood matters: Divergent patterns of stress-induced plasticity across the brain. Nature Neuroscience. 2015; 18 (10):1364–1375. [ PubMed : 26404711 ]
• Cole DA, Peeke LG, Ingold C. Characterological and behavioral self-blame in children: Assessment and development considerations. Development and Psychopathology. 1996; 8 (02):381–397.
• Cook CR, Williams KR, Guerra NG, Kim TE, Sadek S. Predictors of bullying and victimization in childhood and adolescence: A meta-analytic investigation. School Psychology Quarterly. 2010; 25 (2):65–83.
• Copeland WE, Wolke D, Angold A, Costello EJ. Adult psychiatric outcomes of bullying and being bullied by peers in childhood and adolescence. Journal of the American Medical Association Psychiatry. 2013; 70 (4):419–426. [ PMC free article : PMC3618584 ] [ PubMed : 23426798 ]
• Copeland WE, Wolke D, Lereya ST, Shanahan L, Worthman C, Costello EJ. Childhood bullying involvement predicts low-grade systemic inflammation into adulthood. Proceedings of the National Academy of Sciences of the United States of America. 2014; 111 (21):7570–7575. [ PMC free article : PMC4040559 ] [ PubMed : 24821813 ]
• Cornell D. School Violence: Fears vs. Facts. New York: Routledge; 2006.
• Cosma A, Balazsi R, Dobrean A, Baban A. Bullying victimization, emotional problems and cognitive emotion regulation in adolescence. Psychology & Health. 2012; 27 :185–188.
• Cougnard A, Marcelis M, Myin-Germeys I, De Graaf R, Vollebergh W, Krabbendam L, Lieb R, Wittchen HU, Henquet C, Spauwen J. Does normal developmental expression of psychosis combine with environmental risk to cause persistence of psychosis? A psychosis proneness–persistence model. Psychological Medicine. 2007; 37 (04):513–527. [ PubMed : 17288646 ]
• Crick NR, Dodge KA. A review and reformulation of social information-processing mechanisms in children's social adjustment. Psychological Bulletin. 1994; 115 (1):74–101.
• Cunningham T, Hoy K, Shannon C. Does childhood bullying lead to the development of psychotic symptoms? A meta-analysis and review of prospective studies. Psychosis. 2015; 8 (1):1–12.
• Dahl RE, Gunnar MR. Heightened stress responsiveness and emotional reactivity during pubertal maturation: Implications for psychopathology. Development and Psychopathology. 2009; 21 (01):1–6. [ PubMed : 19144219 ]
• Dallman MF, Pecoraro N, Akana SF, La Fleur SE, Gomez F, Houshyar H, Bell M, Bhatnagar S, Laugero KD, Manalo S. Chronic stress and obesity: A new view of “comfort food.” Proceedings of the National Academy of Sciences of the United States of America. 2003; 100 (20):11696–11701. [ PMC free article : PMC208820 ] [ PubMed : 12975524 ]
• Danese A, Tan M. Childhood maltreatment and obesity: Systematic review and meta-analysis. Molecular Psychiatry. 2014; 19 (5):544–554. [ PubMed : 23689533 ]
• Danese A, Pariante CM, Caspi A, Taylor A, Poulton R. Childhood maltreatment predicts adult inflammation in a life-course study. Proceedings of the National Academy of Sciences of the United States of America. 2007; 104 (4):1319–1324. [ PMC free article : PMC1783123 ] [ PubMed : 17229839 ]
• de Bruyn E, Cillessen A, Wissink I. Associations of peer acceptance and perceived popularity with bullying and victimization in early adolescence. Journal of Early Adolescence. 2010; 30 (4):543–566.
• Dick DM, Agrawal A, Keller MC, Adkins A, Aliev F, Monroe S, Hewitt JK, Kendler KS, Sher KJ. Candidate gene–environment interaction research: Reflections and recommendations. Perspectives on Psychological Science. 2015; 10 (1):37–59. [ PMC free article : PMC4302784 ] [ PubMed : 25620996 ]
• Didden R, Scholte RHJ, Korzilius H, de Moor JMH, Vermeulen A, O'Reilly M, Lang R, Lancioni GE. Cyberbullying among students with intellectual and developmental disability in special education settings. Developmental Neurorehabilitation. 2009; 12 (3):146–151. [ PubMed : 19466622 ]
• Dijkstra JK, Lindenberg S, Veenstra R. Beyond the class norm: Bullying behavior of popular adolescents and its relation to peer acceptance and rejection. Journal of Abnormal Child Psychology. 2008; 36 (8):1289–1299. [ PubMed : 18607717 ]
• Dodge KA. Cognitive Perspectives on Children's Social and Behavioral Development: The Minnesota Symposia on Child Psychology, Volume 18. Perlmutter M, editor. New York: Psychology Press; 1986. pp. 77–125. (A social information processing model of social competence in children).
• Dodge KA, Bates JE, Pettit GS. Mechanisms in the cycle of violence. Science. 1990; 250 (4988):1678–1683. [ PubMed : 2270481 ]
• Duncan LE. Paying attention to all results, positive and negative. Journal of the American Academy of Child & Adolescent Psychiatry. 2013; 52 (5):462–465. [ PubMed : 23622847 ]
• Duncan LE, Keller MC. A critical review of the first 10 years of candidate gene-by-environment interaction research in psychiatry. Perspectives. 2011; 168 (10):1041–1049. [ PMC free article : PMC3222234 ] [ PubMed : 21890791 ]
• Duncan LE, Pollastri AR, Smoller JW. Mind the gap: Why many geneticists and psychological scientists have discrepant views about gene–environment interaction (G × E) research. American Psychologist. 2014; 69 (3):249–268. [ PMC free article : PMC7446184 ] [ PubMed : 24750075 ]
• Eisenberger NI. The neural bases of social pain: Evidence for shared representations with physical pain. Psychosomatic Medicine. 2012; 74 (2):126–135. [ PMC free article : PMC3273616 ] [ PubMed : 22286852 ]
• Eisenberger NI, Lieberman MD. Why rejection hurts: A common neural alarm system for physical and social pain. Trends in Cognitive Sciences. 2004; 8 (7):294–300. [ PubMed : 15242688 ]
• Eisenberger NI, Lieberman MD, Williams KD. Does rejection hurt? An fMRI study of social exclusion. Science. 2003; 302 (5643):290–292. [ PubMed : 14551436 ]
• Epel ES, Blackburn EH, Lin J, Dhabhar FS, Adler NE, Morrow JD, Cawthon RM. Accelerated telomere shortening in response to life stress. Proceedings of the National Academy of Sciences of the United States of America. 2004; 101 (49):17312–17315. [ PMC free article : PMC534658 ] [ PubMed : 15574496 ]
• Espelage DL, Swearer SM, editors. Bullying in American Schools: A Social-Ecological Perspective on Prevention and Intervention. Mahwah, NJ: Lawrence Erlbaum Associates; 2004.
• Espelage DL, Hong JS, Rao MA, Low S. Associations between peer victimization and academic performance. Theory Into Practice. 2013; 52 (4):233–240.
• Espinoza G, Gonzales NA, Fuligni AJ. Daily school peer victimization experiences among Mexican-American adolescents: Associations with psychosocial, physical, and school adjustment. Journal of Youth and Adolescence. 2013; 42 (12):1775–1788. [ PMC free article : PMC3951444 ] [ PubMed : 23238764 ]
• Euston DR, Gruber AJ, McNaughton BL. The role of medial prefrontal cortex in memory and decision making. Neuron. 2012; 76 (6):1057–1070. [ PMC free article : PMC3562704 ] [ PubMed : 23259943 ]
• Evans GW, Kim P, Ting AH, Tesher HB, Shannis D. Cumulative risk, maternal responsiveness, and allostatic load among young adolescents. Developmental Psychology. 2007; 43 (2):341. [ PubMed : 17352543 ]
• Faris R, Ennett S. Adolescent aggression: The role of peer group status motives, peer aggression, and group characteristics. Social Networks. 2012; 34 (4):371–378. [ PMC free article : PMC4138540 ] [ PubMed : 25152562 ]
• Farmer TW, Estell DB, Bishop JL, O'Neal KK, Cairns BD. Rejected bullies or popular leaders? The social relations of aggressive subtypes of rural African American early adolescents. Developmental Psychology. 2003; 39 (6):992–1004. [ PubMed : 14584980 ]
• Fein RA, Vossekuil B, Pollack WS, Borum R, Modzeleski W, Reddy M. Threat Assessment in Schools: A Guide to Managing Threatening Situations and Creating Safe School Climates. Washington, DC: U.S. Department of Education, Office of Elementary and Secondary Education, Safe and Drug-Free Schools Program and U.S. Secret Service, National Threat Assessment Center; 2002.
• Feldman MA, Ojanen T, Gesten EL, Smith-Schrandt H, Brannick M, Totura CMW, Alexander L, Scanga D, Brown K. The effects of middle school bullying and victimization on adjustment through high school: Growth modeling of achievement, school attendance, and disciplinary trajectories. Psychology in the Schools. 2014; 51 (10):1046–1062.
• Finkelhor D, Ormrod RK, Turner HA, Hamby SL. Measuring poly-victimization using the juvenile victimization questionnaire. Child Abuse & Neglect. 2005; 29 (11):1297–1312. [ PubMed : 16274741 ]
• Finkelhor D, Ormrod RK, Turner HA. Poly-victimization: A neglected component in child victimization. Child Abuse & Neglect. 2007; 31 (1):7–26. [ PubMed : 17224181 ]
• Finkelhor D, Ormrod RK, Turner HA. Lifetime assessment of poly-victimization in a national sample of children and youth. Child Abuse & Neglect. 2009; 33 (7):403–411. [ PubMed : 19589596 ]
• Flannery DJ, Modzeleski W, Kretschmar JM. Violence and school shootings. Current Psychiatry Reports. 2013; 15 (1):1–7. [ PubMed : 23254623 ]
• Flouri E, Buchanan A. The role of mother involvement and father involvement in adolescent bullying behavior. Journal of Interpersonal Violence. 2003; 18 (6):634–644.
• Ford JD, Elhai JD, Connor DF, Frueh BC. Poly-victimization and risk of posttraumatic, depressive, and substance use disorders and involvement in delinquency in a national sample of adolescents. Journal of Adolescent Health. 2010; 46 (6):545–552. [ PubMed : 20472211 ]
• Ford JD, Grasso DJ, Hawke J, Chapman JF. Poly-victimization among juvenile justice-involved youths. Child Abuse & Neglect. 2013; 37 (10):788–800. [ PubMed : 23428165 ]
• Forero R, McLellan L, Rissel C, Bauman A. Bullying behaviour and psychosocial health among school students in New South Wales, Australia, Cross-Sectional Survey. BMJ. 1999; 319 (7206):344–348. [ PMC free article : PMC28186 ] [ PubMed : 10435953 ]
• Ganzel BL, Kim P, Glover GH, Temple E. Resilience after 9/11: Multimodal neuroimaging evidence for stress-related change in the healthy adult brain. Neuroimage. 2008; 40 (2):788–795. [ PMC free article : PMC2405811 ] [ PubMed : 18234524 ]
• Gastic B. School truancy and the disciplinary problems of bullying victims. Educational Review. 2008; 60 (4):391–404.
• Gee DG, Gabard-Durnam L, Telzer EH, Humphreys KL, Goff B, Shapiro M, Flannery J, Lumian DS, Fareri DS, Caldera C. Maternal buffering of human amygdala-prefrontal circuitry during childhood but not during adolescence. Psychological Science. 2014 [ PMC free article : PMC4377225 ] [ PubMed : 25280904 ] [ CrossRef ]
• Gibb SJ, Horwood LJ, Fergusson DM. Bullying victimization/perpetration in childhood and later adjustment: Findings from a 30-year longitudinal study. Journal of Aggression, Conflict and Peace Research. 2011; 3 (2):82–88.
• Giedd JN, Blumenthal J, Jeffries NO, Castellanos FX, Liu H, Zijdenbos A, Paus T, Evans AC, Rapoport JL. Brain development during childhood and adolescence: A longitudinal MRI study. Nature Neuroscience. 1999; 2 (10):861–863. [ PubMed : 10491603 ]
• Gini G. Associations between bullying behaviour, psychosomatic complaints, emotional and behavioural problems. Journal of Paediatrics and Child Health. 2008; 44 (9):492–497. [ PubMed : 17608653 ]
• Gini G, Pozzoli T. Association between bullying and psychosomatic problems: A meta-analysis. Pediatrics. 2009; 123 (3):1059–1065. [ PubMed : 19255040 ]
• Gini G, Pozzoli T. Bullied children and psychosomatic problems: A meta-analysis. Pediatrics. 2013; 132 (4):720–729. [ PubMed : 24043275 ]
• Glew GM, Fan MY, Katon W, Rivara FP, Kernic MA. Bullying, psychosocial adjustment, and academic performance in elementary school. Archives of Pediatrics and Adolescent Medicine. 2005; 159 (11):1026–1031. [ PubMed : 16275791 ]
• Glew GM, Fan MY, Katon W, Rivara FP. Bullying and school safety. Journal of Pediatrics. 2008; 152 (1):123–128. [ PMC free article : PMC3839286 ] [ PubMed : 18154913 ]
• Graham S. Peer victimization in school: Exploring the ethnic context. Current Directions in Psychological Science. 2006; 15 (6):317–321.
• Graham S, Bellmore AD. Peer victimization and mental health during early adolescence. Theory into Practice. 2007; 46 (2):138–146.
• Graham S, Juvonen J. Self-blame and peer victimization in middle school: An attributional analysis. Developmental Psychology. 1998; 34 (3):587–599. [ PubMed : 9597367 ]
• Graham S, Bellmore AD, Mize J. Peer victimization, aggression, and their co-occurrence in middle school: Pathways to adjustment problems. Journal of Abnormal Child Psychology. 2006; 34 (3):349–364. [ PubMed : 16648999 ]
• Graham S, Bellmore A, Nishina A, Juvonen J. “It must be me”: Ethnic diversity and attributions for peer victimization in middle school. Journal of Youth and Adolescence. 2009; 38 (4):487–499. [ PubMed : 19636723 ]
• Greenberg DB. Somatization: Epidemiology, Pathogenesis, Clinical Features, Medical Evaluation, and Diagnosis. 2016. [June 2016]. http://www ​.uptodate.com ​/contents/somatizationtreatment-and-prognosis?source ​=see_link .
• Gross JJ. Emotion regulation in adulthood: Timing is everything. Current Directions in Psychological Science. 2001; 10 (6):214–219.
• Hager AD, Leadbeater BJ. The longitudinal effects of peer victimization on physical health from adolescence to young adulthood. Journal of Adolescent Health. 2016; 58 (3):330–336. [ PubMed : 26704181 ]
• Hanish LD, Eisenberg N, Fabes RA, Spinrad TL, Ryan P, Schmidt S. The expression and regulation of negative emotions: Risk factors for young children's peer victimization. Development and Psychopathology. 2004; 16 (02):335–353. [ PubMed : 15487599 ]
• Hanson JL, Nacewicz BM, Sutterer MJ, Cayo AA, Schaefer SM, Rudolph KD, Shirtcliff EA, Pollak SD, Davidson RJ. Behavioral problems after early life stress: Contributions of the hippocampus and amygdala. Biological Psychiatry. 2015; 77 (4):314–323. [ PMC free article : PMC4241384 ] [ PubMed : 24993057 ]
• Harris JR. Where is the child's environment? A group socialization theory of development. Psychological Review. 1995; 102 (3):458–489.
• Harvey AG, Tang NK. (Mis) perception of sleep in insomnia: A puzzle and a resolution. Psychological Bulletin. 2012; 138 (1):77–101. [ PMC free article : PMC3277880 ] [ PubMed : 21967449 ]
• Hawker DS, Boulton MJ. Twenty years' research on peer victimization and psychosocial maladjustment: A meta-analytic review of cross-sectional studies. Journal of Child Psychology and Psychiatry. 2000; 41 (4):441–455. [ PubMed : 10836674 ]
• Heim C, Owens MJ, Plotsky PM, Nemeroff CB. Persistent changes in corticotropin-releasing factor systems due to early life stress: Relationship to the pathophysiology of major depression and post-traumatic stress disorder. Psychopharmacology Bulletin. 1997; 33 (2):185–192. [ PubMed : 9230630 ]
• Hennessy MB, Kaiser S, Sachser N. Social buffering of the stress response: Diversity, mechanisms, and functions. Frontiers in Neuroendocrinology. 2009; 30 (4):470–482. [ PubMed : 19545584 ]
• Hennessy MB, Schiml PA, Willen R, Watanasriyakul W, Johnson J, Garrett T. Selective social buffering of behavioral and endocrine responses and Fos induction in the prelimbic cortex of infants exposed to a novel environment. Developmental Psychobiology. 2015; 57 (1):50–62. [ PubMed : 25355379 ]
• Herts KL, McLaughlin KA, Hatzenbuehler ML. Emotion dysregulation as a mechanism linking stress exposure to adolescent aggressive behavior. Journal of Abnormal Child Psychology. 2012; 40 (7):1111–1122. [ PMC free article : PMC3448707 ] [ PubMed : 22466516 ]
• Holt MK, Vivolo-Kantor AM, Polanin JR, Holland KM, DeGue S, Matjasko JL, Wolfe M, Reid G. Bullying and suicidal ideation and behaviors: A meta-analysis. Pediatrics. 2015; 135 (2):e496–e509. [ PMC free article : PMC4702491 ] [ PubMed : 25560447 ]
• Hostinar CE, Sullivan RM, Gunnar MR. Psychobiological mechanisms underlying the social buffering of the hypothalamic–pituitary–adrenocortical axis: A review of animal models and human studies across development. Psychological Bulletin. 2014; 140 (1):256–282. [ PMC free article : PMC3844011 ] [ PubMed : 23607429 ]
• Hostinar CE, Johnson AE, Gunnar MR. Parent support is less effective in buffering cortisol stress reactivity for adolescents compared to children. Developmental Science. 2015; 18 (2):281–297. [ PMC free article : PMC4270957 ] [ PubMed : 24942038 ]
• Huesmann LR, Guerra NG. Children's normative beliefs about aggression and aggressive behavior. Journal of Personality and Social Psychology. 1997; 72 (2):408–419. [ PubMed : 9107008 ]
• Hunter SC, Durkin K, Boyle JM, Booth JN, Rasmussen S. Adolescent bullying and sleep difficulties. Europe's Journal of Psychology. 2014; 10 (4):740–755.
• Institute of Medicine and National Research Council. Building Capacity to Reduce Bullying: Workshop Summary. Washington, DC: The National Academies Press; 2014a. [ PubMed : 25232636 ]
• Institute of Medicine and National Research Council. New Directions in Child Abuse and Neglect Research. Washington, DC: The National Academies Press; 2014b. [ PubMed : 24757747 ]
• Inzlicht M, McKay L, Aronson J. Stigma as ego depletion: How being the target of prejudice affects self-control. Psychological Science. 2006; 17 (3):262–269. [ PubMed : 16507068 ]
• Iyer PA, Dougall AL, Jensen-Campbell LA. Are some adolescents differentially susceptible to the influence of bullying on depression? Journal of Research in Personality. 2013; 47 (4):272–281.
• Janoff-Bulman R. Characterological versus behavioral self-blame: Inquiries into depression and rape. Journal of Personality and Social Psychology. 1979; 37 (10):1798–1809. [ PubMed : 512837 ]
• Jovanovic T, Smith A, Gamwell K, Nylocks M, Norrholm SD, Ressler KJ, Bradley B. Psychophysiological biomarkers of anxiety in children at high risk for trauma exposure. Biological Psychiatry. 2013; 73 (9):17S–17S.
• Judd LL, Schettler PJ, Brown ES, Wolkowitz OM, Sternberg EM, Bender BG, Bulloch K, Cidlowski JA, de Kloet ER, Fardet L. Adverse consequences of glucocorticoid medication: Psychological, cognitive, and behavioral effects. American Journal of Psychiatry. 2014; 171 (10):1045–1051. [ PubMed : 25272344 ]
• Juvonen J, Graham S. Bullying in schools: The power of bullies and the plight of victims. Annual Review of Psychology. 2014; 65 (1):159–185. [ PubMed : 23937767 ]
• Juvonen J, Nishina A, Graham S. Peer harassment, psychological adjustment, and school functioning in early adolescence. Journal of Educational Psychology. 2000; 92 (2):349–359.
• Juvonen J, Graham S, Schuster MA. Bullying among young adolescents: The strong, the weak, and the troubled. Pediatrics. 2003; 112 (6):1231–1237. [ PubMed : 14654590 ]
• Juvonen J, Wang Y, Espinoza G. Bullying experiences and compromised academic performance across middle school grades. Journal of Early Adolescence. 2011; 31 (1):152–173.
• Kalmakis KA, Chandler GE. Health consequences of adverse childhood experiences: A systematic review. Journal of the American Association of Nurse Practitioners. 2015; 27 (8):457–465. [ PubMed : 25755161 ]
• Karg K, Burmeister M, Shedden K, Sen S. The serotonin transporter promoter variant (5-HTTLPR), stress, and depression meta-analysis revisited: Evidence of genetic moderation. Archives of General Psychiatry. 2011; 68 (5):444–454. [ PMC free article : PMC3740203 ] [ PubMed : 21199959 ]
• Kidger J, Heron J, Leon DA, Tilling K, Lewis G, Gunnell D. Self-reported school experience as a predictor of self-harm during adolescence: A prospective cohort study in the south west of England (ALSPAC). Journal of Affective Disorders. 2015; 173 :163–169. [ PMC free article : PMC4286629 ] [ PubMed : 25462412 ]
• Kiecolt-Glaser JK, Gouin JP, Weng NP, Malarkey WB, Beversdorf DQ, Glaser R. Childhood adversity heightens the impact of later-life caregiving stress on telomere length and inflammation. Psychosomatic Medicine. 2011; 73 (1):16–22. [ PMC free article : PMC3051180 ] [ PubMed : 21148804 ]
• Kim YS, Leventhal B. Bullying and suicide. A review. International Journal of Adolescent Medicine and Health. 2008; 20 (2):133–154. [ PubMed : 18714552 ]
• Kim JH, Richardson R. New findings on extinction of conditioned fear early in development: Theoretical and clinical implications. Biological Psychiatry. 2010; 67 (4):297–303. [ PubMed : 19846065 ]
• Kim YS, Leventhal BL, Koh YJ, Hubbard A, Boyce WT. School bullying and youth violence: Causes or consequences of psychopathologic behavior? Archives of General Psychiatry. 2006; 63 (9):1035–1041. [ PubMed : 16953006 ]
• Kimmel MS, Mahler M. Adolescent masculinity, homophobia, and violence: Random school shootings, 1982-2001. American Behavioral Scientist. 2003; 46 (10):1439–1458.
• Klein J. The Bully Society: School Shootings and the Crisis of Bullying in America's Schools. New York: New York University Press; 2012.
• Kliewer W. Violence exposure and cortisol responses in urban youth. International Journal of Behavioral Medicine. 2006; 13 (2):109–120. [ PubMed : 16712428 ]
• Kliewer W, Dibble AE, Goodman KL, Sullivan TN. Physiological correlates of peer victimization and aggression in African American urban adolescents. Development and Psychopathology. 2012; 24 (2):637–650. [ PMC free article : PMC5828867 ] [ PubMed : 22559136 ]
• Klomek AB, Marrocco F, Kleinman M, Schonfeld IS, Gould MS. Bullying, depression, and suicidality in adolescents. Journal of the American Academy of Child & Adolescent Psychiatry. 2007; 46 (1):40–49. [ PubMed : 17195728 ]
• Klomek AB, Sourander A, Niemelä S, Kumpulainen K, Piha J, Tamminen T, Almqvist F, Gould MS. Childhood bullying behaviors as a risk for suicide attempts and completed suicides: A population-based birth cohort study. Journal of the American Academy of Child & Adolescent Psychiatry. 2009; 48 (3):254–261. [ PubMed : 19169159 ]
• Klomek AB, Sourander A, Gould M. The association of suicide and bullying in childhood to young adulthood: A review of cross-sectional and longitudinal research findings. Canadian Journal of Psychiatry. 2010; 55 (5):282–288. [ PubMed : 20482954 ]
• Klomek AB, Sourander A, Elonheimo H. Bullying by peers in childhood and effects on psychopathology, suicidality, and criminality in adulthood. The Lancet Psychiatry. 2015; 2 (10):930–941. [ PubMed : 26462227 ]
• Knack JM, Gomez HL, Jensen-Campbell LA. Social Pain: Neuropsychological and Health Implications of Loss and Exclusion. MacDonald G, Jensen-Campbell LA, editors. Washington, DC: American Psychological Association; 2011a. pp. 215–236. (Bullying and its long-term health implications).
• Knack JM, Jensen-Campbell LA, Baum A. Worse than sticks and stones? Bullying is associated with altered HPA axis functioning and poorer health. Brain and Cognition. 2011b; 77 (2):183–190. [ PubMed : 21839567 ]
• Knack J, Vaillancourt T, Hutcherson A. Psychology of Victimization. Hutcherson AN, editor. New York: Nova Science; 2012a. [June 2016]. pp. 205–218. (Evidence of altered cortisol levels across child maltreatment, intimate partner abuse, and peer victimization). https://www ​.novapublishers ​.com/catalog/product_info ​.php?products_id=27225 .
• Knack JM, Tsar V, Vaillancourt T, Hymel S, McDougall P. What protects rejected adolescents from also being bullied by their peers? The moderating role of peer-valued characteristics. Journal of Research on Adolescence. 2012b; 22 (3):467–479.
• Kochel KP, Ladd GW, Rudolph KD. Longitudinal associations among youth depressive symptoms, peer victimization, and low peer acceptance: An interpersonal process perspective. Child Development. 2012; 83 (2):637–650. [ PMC free article : PMC3305833 ] [ PubMed : 22313098 ]
• Kochenderfer BJ, Ladd GW. Peer victimization: Cause or consequence of school maladjustment? Child Development. 1996; 67 (4):1305–1317. [ PubMed : 8890485 ]
• Kowalski RM, Limber SP. Psychological, physical, and academic correlates of cyberbullying and traditional bullying. Journal of Adolescent Health. 2013; 53 (1):S13–S20. [ PubMed : 23790195 ]
• Kretschmer T, Dijkstra JK, Ormel J, Verhulst FC, Veenstra R. Dopamine receptor D4 gene moderates the effect of positive and negative peer experiences on later delinquency: The Tracking Adolescents' Individual Lives Survey study. Development and Psychopathology. 2013; 25 (4 pt. 1):1107–1117. [ PubMed : 24229552 ]
• Kross E, Berman MG, Mischel W, Smith EE, Wager TD. Social rejection shares somatosensory representations with physical pain. Proceedings of the National Academy of Sciences of the United States of America. 2011; 108 (15):6270–6275. [ PMC free article : PMC3076808 ] [ PubMed : 21444827 ]
• Kumpulainen K, Räsänen E, Puura K. Psychiatric disorders and the use of mental health services among children involved in bullying. Aggressive Behavior. 2001; 27 (2):102–110.
• Ladd GW, Kochenderfer-Ladd B. Identifying victims of peer aggression from early to middle childhood: Analysis of cross-informant data for concordance, estimation of relational adjustment, prevalence of victimization, and characteristics of identified victims. Psychological Assessment. 2002; 14 (1):74–96. [ PubMed : 11911051 ]
• Lake A, Chan M. Putting science into practice for early child development. The Lancet. 2015; 385 (9980):1816–1817. [ PubMed : 25245180 ]
• Langman P. Rampage school shooters: A typology. Aggression and Violent Behavior. 2009; 14 (1):79–86.
• Langman P. School Shooters: Understanding High School, College, and Adult Perpetrators. Lanham, MD: Rowman & Littlefield; 2015.
• Leary M, Kowalski R, Smith L, Phillips S. Teasing, rejection, and violence: Case studies of the school shootings. Aggressive Behavior. 2003; 29 (3):202–214.
• Lee HS, Lee JE, Lee KU, Kim YH. Neural changes associated with emotion processing in children experiencing peer rejection: A functional MRI study. Journal of Korean Medical Science. 2014; 29 (9):1293–1300. [ PMC free article : PMC4168185 ] [ PubMed : 25246750 ]
• Lereya ST, Copeland WE, Costello EJ, Wolke D. Adult mental health consequences of peer bullying and maltreatment in childhood: Two cohorts in two countries. The Lancet Psychiatry. 2015; 2 (6):524–531. [ PMC free article : PMC4580734 ] [ PubMed : 26360448 ]
• Lim L, Radua J, Rubia K. Gray matter abnormalities in childhood maltreatment: A voxel-wise meta-analysis. American Journal of Psychiatry. 2014; 171 (8):854–863. [ PubMed : 24781447 ]
• Lim L, Hart H, Mehta MA, Simmons A, Mirza K, Rubia K. Neural correlates of error processing in young people with a history of severe childhood abuse: An fMRI study. American Journal of Psychiatry. 2015; 172 (9):892–900. [ PubMed : 25882324 ]
• Liston C, McEwen B, Casey B. Psychosocial stress reversibly disrupts prefrontal processing and attentional control. Proceedings of the National Academy of Sciences of the United States of America. 2009; 106 (3):912–917. [ PMC free article : PMC2621252 ] [ PubMed : 19139412 ]
• Lodge J, Frydenberg E. The role of peer bystanders in school bullying: Positive steps toward promoting peaceful schools. Theory Into Practice. 2005; 44 (4):329–336.
• Lupien SJ, Fiocco A, Wan N, Maheu F, Lord C, Schramek T, Tu MT. Stress hormones and human memory function across the lifespan. Psychoneuroendocrinology. 2005; 30 (3):225–242. [ PubMed : 15511597 ]
• Madfis E. The Risk of School Rampage: Assessing and Preventing Threats of School Violence. New York: Polgrave MacMillan; 2014.
• Mahady Wilton MM, Craig WM, Pepler DJ. Emotional regulation and display in classroom victims of bullying: Characteristic expressions of affect, coping styles, and relevant contextual factors. Social Development. 2000; 9 (2):227–245.
• Márquez C, Poirier GL, Cordero MI, Larsen MH, Groner A, Marquis J, Magistretti PJ, Trono D, Sandi C. Peripuberty stress leads to abnormal aggression, altered amygdala and orbitofrontal reactivity and increased prefrontal MAOA gene expression. Translational Psychiatry. 2013; 3 (1):1–12. [ PMC free article : PMC3566724 ] [ PubMed : 23321813 ]
• McCormick CM, Mathews IZ. HPA function in adolescence: Role of sex hormones in its regulation and the enduring consequences of exposure to stressors. Pharmacology Biochemistry and Behavior. 2007; 86 (2):220–233. [ PubMed : 16901532 ]
• McDermott R, Tingley D, Cowden J, Frazzetto G, Johnson DD. Monoamine oxidase A gene (MAOA) predicts behavioral aggression following provocation. Proceedings of the National Academy of Sciences of the United States of America. 2009; 106 (7):2118–2123. [ PMC free article : PMC2650118 ] [ PubMed : 19168625 ]
• McDougall P, Vaillancourt T. Long-term adult outcomes of peer victimization in childhood and adolescence: Pathways to adjustment and maladjustment. American Psychologist. 2015; 70 (4):300–310. [ PubMed : 25961311 ]
• McEwen BS. Synaptic Stress and Pathogenesis of Neuropsychiatric Disorders. Popoli M, Diamond D, Sanacora G, editors. New York: Springer; 2014. pp. 1–18. (The brain on stress: The good and the bad).
• McEwen BS, Karatsoreos IN. Sleep deprivation and circadian disruption: Stress, allostasis, and allostatic load. Sleep Medicine Clinics. 2015; 10 (1):1–10. [ PMC free article : PMC8935364 ] [ PubMed : 26055668 ]
• McEwen BS, McEwen CA. Emerging Trends in the Social and Behavioral Sciences: An Interdisciplinary, Searchable, and Linkable Resource. Scott RA, Kosslyn SM, Pinkerton N, editors. New York: J. Wiley; 2015. pp. 1–15. (Social, psychological, and physiological reactions to stress).
• McEwen BS, Morrison JH. The brain on stress: Vulnerability and plasticity of the prefrontal cortext over the life course. Neuron. 2013; 79 (1):16–29. [ PMC free article : PMC3753223 ] [ PubMed : 23849196 ]
• McEwen BS, Gray JD, Nasca C. Recognizing resilience: Learning from the effects of stress on the brain. Neurobiology of Stress. 2015; 1 :1–11. [ PMC free article : PMC4260341 ] [ PubMed : 25506601 ]
• McGaugh JL. Consolidating memories. Annual Review of Psychology. 2015; 66 :1–24. [ PubMed : 25559113 ]
• McGee TR, Scott JG, McGrath JJ, Williams GM, O'Callaghan M, Bor W, Najman JM. Young adult problem behaviour outcomes of adolescent bullying. Journal of Aggression, Conflict and Peace Research. 2011; 3 (2):110–114.
• McGowan PO, Sasaki A, D'Alessio AC, Dymov S, Labonté B, Szyf M, Turecki G, Meaney MJ. Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse. Nature Neuroscience. 2009; 12 (3):342–348. [ PMC free article : PMC2944040 ] [ PubMed : 19234457 ]
• McGowan PO, Suderman M, Sasaki A, Huang T, Hallett M, Meaney MJ, Szyf M. Broad epigenetic signature of maternal care in the brain of adult rats. PLoS One. 2011; 6 (2) [August 2016]; http://journals ​.plos ​.org/plosone/article?id=10 ​.1371/journal.pone.0014739 . [ PMC free article : PMC3046141 ] [ PubMed : 21386994 ]
• McLaughlin KA, Hatzenbuehler ML, Hilt LM. Emotion dysregulation as a mechanism linking peer victimization to internalizing symptoms in adolescents. Journal of Consulting and Clinical Psychology. 2009; 77 (5):894–904. [ PMC free article : PMC2778003 ] [ PubMed : 19803569 ]
• Milaid MR, Quirk GJ. Fear extinction as a model for translational neuroscience: Ten years of progress. Annual Review of Psychology. 2012; 63 :129–151. [ PMC free article : PMC4942586 ] [ PubMed : 22129456 ]
• Miller GE, Chen E, Zhou ES. If it goes up, must it come down? Chronic stress and the hypothalamic-pituitary-adrenocortical axis in humans. Psychological Bulletin. 2007; 133 (1):25–45. [ PubMed : 17201569 ]
• Miller GE, Chen E. Harsh family climate in early life presages the emergence of a proinflammatory phenotype in adolescence. Psychological Science. 2010; 21 (6):848–856. [ PMC free article : PMC3207635 ] [ PubMed : 20431047 ]
• Miller-Graff LE, Cater ÅK, Howell KH, Graham-Bermann SA. Victimization in childhood: General and specific associations with physical health problems in young adulthood. Journal of Psychosomatic Research. 2015; 70 (4):269–271. [ PubMed : 26208402 ]
• Moffitt TE. Teen-aged mothers in contemporary Britain. Journal of Child Psychology and Psychiatry. 2002; 43 (6):727–742. [ PubMed : 12236608 ]
• Montoya ER, Terburg D, Bos PA, Van Honk J. Testosterone, cortisol, and serotonin as key regulators of social aggression: A review and theoretical perspective. Motivation and Emotion. 2012; 36 (1):65–73. [ PMC free article : PMC3294220 ] [ PubMed : 22448079 ]
• Moriceau S, Sullivan RM. Maternal presence serves as a switch between learning fear and attraction in infancy. Nature Neuroscience. 2006; 9 (8):1004–1006. [ PMC free article : PMC1560090 ] [ PubMed : 16829957 ]
• Mulvey E, Cauffman E. The inherent limits of predicting school violence. American Psychologist. 2001; 56 (10):797–802. [ PubMed : 11675986 ]
• Musher-Eizenman DR, Boxer P, Danner S, Dubow EF, Goldstein SE, Heretick DML. Social-cognitive mediators of the relation of environmental and emotion regulation factors to children's aggression. Aggressive Behavior. 2004; 30 (5):389–408.
• Nair HP, Gonzalez-Lima F. Extinction of behavior in infant rats: Development of functional coupling between septal hippocampal and vental tegmental regions. The Journal of Neuroscience. 1999; 19 (19):8646–8655. [ PMC free article : PMC6783035 ] [ PubMed : 10493765 ]
• Nakamoto J, Schwartz D. Is peer victimization associated with academic achievement? A meta-analytic review. Social Development. 2010; 19 (2):221–242.
• Nansel TR, Overpeck M, Pilla RS, Ruan WJ, Simons-Morton B, Scheidt P. Bullying behaviors among U.S. youth: Prevalence and association with psychosocial adjustment. Journal of the American Medical Association. 2001; 285 (16):2094–2100. [ PMC free article : PMC2435211 ] [ PubMed : 11311098 ]
• Nansel TR, Haynie DL, Simonsmorton BG. The association of bullying and victimization with middle school adjustment. Journal of Applied School Psychology. 2003; 19 (2):45–61.
• Nansel TR, Craig W, Overpeck MD, Saluja G, Ruan WJ. Cross-national consistency in the relationship between bullying behaviors and psychosocial adjustment. Archives of Pediatrics and Adolescent Medicine. 2004; 158 (8):730–736. [ PMC free article : PMC2556236 ] [ PubMed : 15289243 ]
• National Research Council and Institute of Medicine; Division of Behavioral and Social Sciences and Education. Deadly Lessons: Understanding Lethal School Violence. Moore MH, Petrie CV, Braga AA, McLaughlin BL, editors. Washington, DC: The National Academies Press; 2003. (Case Studies of School Violence Committee).
• Neary A, Joseph S. Peer victimization and its relationship to self-concept and depression among schoolgirls. Personality and Individual Differences. 1994; 16 (1):183–186.
• Newman KS, Fox C, Harding D, Mehta J, Roth W. Rampage: The Social Roots of School Shootings. New York: Basic Books; 2004.
• Newman ML. Here we go again: Bullying history and cardiovascular responses to social exclusion. Physiology & Behavior. 2014; 133 :76–80. [ PubMed : 24858188 ]
• Nishina A, Juvonen J. Daily reports of witnessing and experiencing peer harassment in middle school. Child Development. 2005; 76 (2):435–450. [ PubMed : 15784092 ]
• Niv S, Tuvblad C, Raine A, Baker LA. Aggression and rule-breaking: Heritability and stability of antisocial behavior problems in childhood and adolescence. Journal of Criminal Justice. 2013; 41 (5):285–291. [ PMC free article : PMC3856338 ] [ PubMed : 24347737 ]
• Nixon C. Current perspectives: The impact of cyberbullying on adolescent health. Adolescent Health, Medicine and Therapeutics. 2014:143–158. [ PMC free article : PMC4126576 ] [ PubMed : 25177157 ]
• O'Brennan LM, Bradshaw CP, Sawyer AL. Examining developmental differences in the social-emotional problems among frequent bullies, victims, and bully/victims. Psychology in the Schools. 2009; 46 (2):100–115.
• Obradovic J, Bush NR, Stamperdahl J, Adler NE, Boyce WT. Biological sensitivity to context: The interactive effects of stress reactivity and family adversity on socioemotional behavior and school readiness. Child Development. 2010; 81 (1):270–289. [ PMC free article : PMC2846098 ] [ PubMed : 20331667 ]
• Olweus D. Bullying at School. What We Know and What We Can Do. Oxford, UK: Blackwell; 1993a.
• Olweus D. Social Withdrawal, Inhibition, and Shyness in Childhood. Rubin KH, Asendorpf JB, editors. New York: Psychology Press; 1993b. pp. 315–341. (Victimization by peers: Antecedents and long-term outcomes).
• Ostrov JM, Kamper KE. Future directions for research on the development of relational and physical peer victimization. Journal of Clinical Child & Adolescent Psychology. 2015; 44 (3):509–519. [ PubMed : 25751392 ]
• O'Toole ME. The School Shooter: A Threat Assessment Perspective. Quantico, VA: US Department of Justice, Federal Bureau of Investigation; 2000.
• O'Toole ME, Folino PJ, Garbarino J, Gorelick SM, Häkkänen-Nyholm H, Meloy JR, Samenow SE, Nishimura YS. Why do young males attack schools? Seven discipline leaders share their perspectives. Violence and Gender. 2014; 1 (1):13–18.
• Ouellet-Morin I, Odgers CL, Danese A, Bowes L, Shakoor S, Papadopoulos AS, Caspi A, Moffitt TE, Arseneault L. Blunted cortisol responses to stress signal social and behavioral problems among maltreated/bullied 12-year-old children. Biological Psychiatry. 2011; 70 (11):1016–1023. [ PMC free article : PMC3816750 ] [ PubMed : 21839988 ]
• Ouellet-Morin I, Wong C, Danese A, Pariante C, Papadopoulos A, Mill J, Arseneault L. Increased serotonin transporter gene (SERT) DNA methylation is associated with bullying victimization and blunted cortisol response to stress in childhood: A longitudinal study of discordant monozygotic twins. Psychological Medicine. 2013; 43 (09):1813–1823. [ PMC free article : PMC4231789 ] [ PubMed : 23217646 ]
• Patchin JW. Bullies move beyond the schoolyard: A preliminary look at cyberbullying. Youth Violence and Juvenile Justice. 2006; 4 (2):148–169.
• Patton DU, Hong JS, Patel S, Kral MJ. A systematic review of research strategies used in qualitative studies on school bullying and victimization. Trauma, Violence, & Abuse. 2015:1–14. [ PubMed : 26092753 ] [ CrossRef ]
• Pattwell SS, Duhoux S, Hartley CA, Johnson DC, Jing D, Elliott MD, Ruberry EJ, Powers A, Mehta N, Yand RR, Soliman F, Glatt CE, Casey BJ, Ninan I, Lee FS. Altered fear learning across development in both mouse and human. Proceedings of the National Academy of Sciences of the United States of America. 2012; 109 (40):16318–16323. [ PMC free article : PMC3479553 ] [ PubMed : 22988092 ]
• Pattwell SS, Lee FS, Casey BJ. Fear learning and memory across adolescent development: Hormones and behavior special issue: Puberty and adolescence. Hormones and Behavior. 2013; 64 (2):380–389. [ PMC free article : PMC3761221 ] [ PubMed : 23998679 ]
• Peeters M, Cillessen AH, Scholte RH. Clueless or powerful? Identifying subtypes of bullies in adolescence. Journal of Youth and Adolescence. 2010; 39 (9):1041–1052. [ PubMed : 20625880 ]
• Perren S, Ettekal I, Ladd G. The impact of peer victimization on later maladjustment: Mediating and moderating effects of hostile and self-blaming attributions. Journal of Child Psychology and Psychiatry. 2012; 54 (1):46–55. [ PMC free article : PMC3527635 ] [ PubMed : 23057732 ]
• Perry R, Sullivan RM. Neurobiology of attachment to an abusive caregiver: Short-term benefits and long-term costs. Developmental Psychobiology. 2014; 56 (8):1626–1634. [ PMC free article : PMC4209208 ] [ PubMed : 24771610 ]
• Plomin R, DeFries JC, Loehlin JC. Genotype-environment interaction and correlation in the analysis of human behavior. Psychological Bulletin. 1977; 84 (2):309–322. [ PubMed : 557211 ]
• Polanin JR, Espelage DL, Pigott TD. A meta-analysis of school-based bullying prevention programs' effects on bystander intervention behavior. School Psychology Review. 2012; 41 (1):47–65.
• Prinstein MJ, Cheah CSL, Guyer AE. Peer victimization, cue interpretation, and internalizing symptoms: Preliminary concurrent and longitudinal findings for children and adolescents. Journal of Clinical Child & Adolescent Psychology. 2005; 34 (1):11–24. [ PubMed : 15677277 ]
• Radley JJ, Rocher AB, Miller M, Janssen WG, Liston C, Hof PR, McEwen BS, Morrison JH. Repeated stress induces dendritic spine loss in the rat medial prefrontal cortex. Cerebral Cortex. 2006; 16 (3):313–320. [ PubMed : 15901656 ]
• Radliff KM, Wheaton JE, Robinson K, Morris J. Illuminating the relationship between bullying and substance use among middle and high school youth. Addictive Behaviors. 2012; 37 (4):569–572. [ PubMed : 22277772 ]
• Rau V, Fanselow MS. Exposure to a stressor produces a long lasting enhancement of fear learning in rats: Original research report. Stress. 2009; 12 (2):125–133. [ PubMed : 18609302 ]
• Reijntjes A, Kamphuis JH, Prinzie P, Telch MJ. Peer victimization and internalizing problems in children: A meta-analysis of longitudinal studies. Child Abuse & Neglect. 2010; 34 (4):244–252. [ PubMed : 20304490 ]
• Reijntjes A, Kamphuis JH, Prinzie P, Boelen PA, Van der Schoot M, Telch MJ. Prospective linkages between peer victimization and externalizing problems in children: A meta-analysis. Aggressive Behavior. 2011; 37 (3):215–222. [ PubMed : 21433031 ]
• Repetti RL, Taylor SE, Seeman TE. Risky families: Family social environments and the mental and physical health of offspring. Psychological Bulletin. 2002; 128 (2):330–366. [ PubMed : 11931522 ]
• Retz W, Retz-Junginger P, Supprian T, Thome J, Rösler M. Association of serotonin transporter promoter gene polymorphism with violence: Relation with personality disorders, impulsivity, and childhood adhd psychopathology. Behavioral Sciences & the Law. 2004; 22 (3):415–425. [ PubMed : 15211560 ]
• Reuter-Rice K. Male adolescent bullying and the school shooter. Journal of School Nursing. 2008; 24 (6):350–359. [ PubMed : 19114465 ]
• Richter-Levin G, Horovitz O, Tsoory MM. Future Directions in Post-Traumatic Stress Disorder: Prevention Diagnosis, and Treatment. Safir MP, Wallach HS, Rizzo A, editors. New York: Springer; 2015. (The early adolescent of “juvenile stress” translational animal model of posttraumatic stress disorder).
• Rigby K, Slee PT. Dimensions of interpersonal relation among Australian children and implications for psychological well-being. Journal of Social Psychology. 1993; 133 (1):33–42. [ PubMed : 8464217 ]
• Rivers I, Noret N. Potential suicide ideation and its association with observing bullying at school. Journal of Adolescent Health. 2013; 53 (1):S32–S36. [ PubMed : 23790198 ]
• Rivers I, Poteat VP, Noret N, Ashurst N. Observing bullying at school: The mental health implications of witness status. School Psychology Quarterly. 2009; 24 (4):211–223.
• Robertson KD. DNA methylation and human disease. Nature Reviews: Genetics. 2005; 6 (8):597–610. [ PubMed : 16136652 ]
• Rocque M. Exploring school rampage shootings: Research, theory, and policy. Social Science Journal. 2012; 49 (3):304–313.
• Rodkin PC. Bullying in American Schools: A Social-Ecological Perspective on Prevention and Intervention. Espelage DL, Swearer SM, editors. Mahwah, NJ: Lawrence Erlbaum Associates; 2004. pp. 87–106. (Peer ecologies of aggression and bullying).
• Rodkin PC, Espelage DL, Hanish LD. A relational framework for understanding bullying: Developmental antecedents and outcomes. American Psychologist. 2015; 70 (4):311–321. [ PubMed : 25961312 ]
• Romeo RD. Pubertal maturation and programming of hypothalamic–pituitary–adrenal reactivity. Frontiers in Neuroendocrinology. 2010; 31 (2):232–240. [ PubMed : 20193707 ]
• Romeo RD. Perspectives on stress resilience and adolescent neurobehavioral function. Neurobiology of Stress. 2015; 1 :128–133. [ PMC free article : PMC4721430 ] [ PubMed : 27589663 ]
• Roth TL. How traumatic experiences leave their signature on the genome: An overview of epigenetic pathways in PTSD. Frontiers in Psychiatry. 2014; 5 (93):1–2. [ PMC free article : PMC4116797 ] [ PubMed : 25132824 ]
• Roth TL, Sweatt JD. Epigenetic marking of the BDNF gene by early-life adverse experiences. Hormones and Behavior. 2011; 59 (3):315–320. [ PMC free article : PMC2948595 ] [ PubMed : 20483357 ]
• Rudolph KD, Troop-Gordon W, Flynn M. Relational victimization predicts children's social-cognitive and self-regulatory responses in a challenging peer context. Developmental Psychology. 2009; 45 (5):1444–1454. [ PMC free article : PMC2780469 ] [ PubMed : 19702404 ]
• Rudolph KD, Miernicki ME, Troop-Gordon W, Davis MM, Telzer EH. Adding insult to injury: Neural sensitivity to social exclusion is associated with internalizing symptoms in chronically peer-victimized girls. Social Cognitive and Affective Neuroscience. 2016 [ PMC free article : PMC4847705 ] [ PubMed : 26892162 ] [ CrossRef ]
• Rueger SY, Jenkins LN. Effects of peer victimization on psychological and academic adjustment in early adolescence. School Psychology Quarterly. 2014; 29 (1):77–88. [ PubMed : 24015982 ]
• Rueger SY, Malecki CK, Demaray MK. Stability of peer victimization in early adolescence: Effects of timing and duration. Journal of School Psychology. 2011; 49 (4):443–464. [ PubMed : 21724000 ]
• Salmivalli C. Bullying and the peer group: A review. Aggression and Violent Behavior. 2010; 15 (2):112–120.
• Salmivalli C, Lagerspetz K, Björkqvist K, Österman K, Kaukiainen A. Bullying as a group process: Participant roles and their relations to social status within the group. Aggressive Behavior. 1996; 22 (1):1–15.
• Salmivalli C, Voeten M, Poskiparta E. Bystanders matter: Associations between reinforcing, defending, and the frequency of bullying behavior in classrooms. Journal of Clinical Child & Adolescent Psychology. 2011; 40 (5):668–676. [ PubMed : 21916686 ]
• Sanchez M, Pollak S. Handbook of Developmental Social Neuroscience. de Haan M, Gunnar MR, editors. New York: Guilford Press; 2009. pp. 497–520. (Socio-emotional development following early abuse and neglect: Challenges and insights from translational research).
• Sandi C, Haller J. Stress and the social brain: Behavioural effects and neurobiological mechanisms. Nature Reviews Neuroscience. 2015; 16 :290–304. [ PubMed : 25891510 ]
• Scarr S, McCartney K. How people make their own environments: A theory of genotype→ environment effects. Child Development. 1983; 52 (2):424–435. [ PubMed : 6683622 ]
• Schacter HL, White SJ, Chang VY, Juvonen J. “Why me?”: Characterological self-blame and continued victimization in the first year of middle school. Journal of Clinical Child & Adolescent Psychology. 2014; 44 (3):446–455. [ PMC free article : PMC6129379 ] [ PubMed : 24483145 ]
• Schwartz D, Dodge KA, Coie JD. The emergence of chronic peer victimization in boys' play groups. Child Development. 1993; 64 (6):1755–1772. [ PubMed : 8112117 ]
• Schwartz D, Gorman AH, Nakamoto J, Toblin RL. Victimization in the peer group and children's academic functioning. Journal of Educational Psychology. 2005; 97 (3):425–435.
• Shakoor S, Jaffee SR, Andreou P, Bowes L, Ambler AP, Caspi A, Moffitt TE, Arseneault L. Mothers and children as informants of bullying victimization: Results from an epidemiological cohort of children. Journal of Abnormal Child Psychology. 2011; 39 (3):379–387. [ PMC free article : PMC4231790 ] [ PubMed : 20938734 ]
• Shalev I, Moffitt TE, Sugden K, Williams B, Houts RM, Danese A, Mill J, Arseneault L, Caspi A. Exposure to violence during childhood is associated with telomere erosion from 5 to 10 years of age: A longitudinal study. Molecular Psychiatry. 2013; 18 (5):576–581. [ PMC free article : PMC3616159 ] [ PubMed : 22525489 ]
• Shen J, Kudrimoti H, McNaughton B, Barnes C. Reactivation of neuronal ensembles in hippocampal dentate gyrus during sleep after spatial experience. Journal of Sleep Research. 1998; 7 (S1):6–16. [ PubMed : 9682188 ]
• Shonkoff JP, Boyce WT, McEwen BS. Neuroscience, molecular biology, and the childhood roots of health disparities: Building a new framework for health promotion and disease prevention. Journal of the American Medical Association. 2009; 301 (21):2252–2259. [ PubMed : 19491187 ]
• Shultz JM, Thoresen S, Flynn BW, Muschert GW, Shaw JA, Espinel Z, Walter FG, Gaither JB, Garcia-Barcena Y, O'Keefe K. Multiple vantage points on the mental health effects of mass shootings. Current Psychiatry Reports. 2014; 16 (9):1–17. [ PubMed : 25085235 ]
• Sigurdson JF, Undheim AM, Wallander JL, Lydersen S, Sund AM. The long-term effects of being bullied or a bully in adolescence on externalizing and internalizing mental health problems in adulthood. Child and Adolescent Psychiatry and Mental Health. 2015; 9 (1):1–13. [ PMC free article : PMC4546259 ] [ PubMed : 26300969 ]
• Sijtsema JJ, Veenstra R, Lindenberg S, Salmivalli C. Empirical test of bullies' status goals: Assessing direct goals, aggression, and prestige. Aggressive Behavior. 2009; 35 :57–67. [ PubMed : 18925635 ]
• Smalley D, Banerjee R. The role of social goals in bullies' and victims' social information processing in response to ambiguous and overtly hostile provocation. Social Development. 2013; 23 (3):593–610.
• Smith PK, Talamelli L, Cowie H, Naylor P, Chauhan P. Profiles of non-victims, escaped victims, continuing victims and new victims of school bullying. British Journal of Educational Psychology. 2004; 74 :565–581. [ PubMed : 15530202 ]
• Sourander A, Jensen P, Rönning JA, Elonheimo H, Niemelä S, Helenius H, Kumpulainen K, Piha J, Tamminen T, Moilanen I, Almqvist F. Childhood bullies and victims and their risk of criminality in late adolescence. Archives of Pediatrics and Adolescent Medicine. 2007; 161 (6):546–552. [ PubMed : 17548758 ]
• Sourander A, Brunstein KA, Kumpulainen K, Puustjärvi A, Elonheimo H, Ristkari T, Tamminen T, Moilanen I, Piha J, Ronning J. Bullying at age eight and criminality in adulthood: Findings from the Finnish Nationwide 1981 Birth Cohort Study. Social Psychiatry and Psychiatric Epidemiology. 2011; 46 (12):1211–1219. [ PubMed : 21120451 ]
• Spear L. The Behavioral Neuroscience of Adolescence. New York: WW Norton & Company; 2010.
• Spear LP. Adolescent neurodevelopment. Journal of Adolescent Health. 2013; 52 (2):S7–S13. [ PMC free article : PMC3982854 ] [ PubMed : 23332574 ]
• Srabstein JC, McCarter RJ, Shao C, Huang ZJ. Morbidities associated with bullying behaviors in adolescents. School based study of American adolescents. International Journal of Adolescent Medicine and Health. 2006; 18 (4):587–596. [ PubMed : 17340850 ]
• Stapinski LA, Bowes L, Wolke D, Pearson RM, Mahedy L, Button KS, Lewis G, Araya R. Peer victimization during adolescence and risk for anxiety disorders in adulthood: A prospective cohort study. Depression and anxiety. 2014; 31 (7):574–582. [ PMC free article : PMC4190687 ] [ PubMed : 24788688 ]
• Sugden K, Arseneault L, Harrington H, Moffitt TE, Williams B, Caspi A. Serotonin transporter gene moderates the development of emotional problems among children following bullying victimization. Journal of the American Academy of Child & Adolescent Psychiatry. 2010; 49 (8):830–840. [ PMC free article : PMC2908591 ] [ PubMed : 20643316 ]
• Swearer SM, Hymel S. Understanding the psychology of bullying: Moving toward a social-ecological diathesis–stress model. American Psychologist. 2015; 70 (4):344–353. [ PubMed : 25961315 ]
• Tharp-Taylor S, Haviland A, D'Amico EJ. Victimization from mental and physical bullying and substance use in early adolescence. Addictive Behaviors. 2009; 34 (6):561–567. [ PMC free article : PMC2707251 ] [ PubMed : 19398162 ]
• Thornberg R, Tenenbaum L, Varjas K, Meyers J, Jungert T, Vanegas G. Bystander motivation in bullying incidents: To intervene or not to intervene? Western Journal of Emergency Medicine. 2012; 13 (3):247–252. [ PMC free article : PMC3415829 ] [ PubMed : 22900122 ]
• Thunfors P, Cornell D. The popularity of middle school bullies. Journal of School Violence. 2008; 7 (1):65–82.
• Tilghman-Osborne C, Cole DA, Felton JW, Ciesla JA. Relation of guilt, shame, behavioral and characterological self-blame to depressive symptoms in adolescents over time. Journal of Social and Clinical Psychology. 2008; 27 (8):809–842. [ PMC free article : PMC4238306 ] [ PubMed : 25419043 ]
• Ttofi MM, Farrington DP, Lösel F, Loeber R. Do the victims of school bullies tend to become depressed later in life? A systematic review and meta-analysis of longitudinal studies. Journal of Aggression, Conflict and Peace Research. 2011; 3 (2):63–73.
• Unnever JD, Cornell DG. The culture of bullying in middle school. Journal of School Violence. 2003; 2 (2):5–27.
• Vaillancourt T, Hymel S, McDougall P. Bullying is power: Implications for school-based intervention strategies. Journal of Applied School Psychology. 2003; 19 (2):157–176.
• Vaillancourt T, Duku E, Decatanzaro D, Macmillan H, Muir C, Schmidt LA. Variation in hypothalamic–pituitary–adrenal axis activity among bullied and non-bullied children. Aggressive Behavior. 2008; 34 (3):294–305. [ PubMed : 18161876 ]
• Vaillancourt T, Decatanzaro D, Duku E, Muir C. Androgen dynamics in the context of children's peer relations: An examination of the links between testosterone and peer victimization. Aggressive Behavior. 2009; 35 (1):103–113. [ PubMed : 19021234 ]
• Vaillancourt T, Hymel S, McDougall P. Bullying in North American Schools. Espelage D, Swearer S, editors. New York: Taylor & Francis; 2010a. pp. 23–33. (Why does bullying hurt so much? Insights from neuroscience).
• Vaillancourt T, McDougall P, Hymel S, Sunderani S. Handbook of Bullying in Schools: An International Perspective. Jimerson SR, Swearer SM, Espelage DL, editors. New York: Routledge; 2010b. pp. 211–222. (The relationship between power and bullying behavior).
• Vaillancourt T, Duku E, Becker S, Schmidt LA, Nicol J, Muir C, MacMillan H. Peer victimization, depressive symptoms, and high salivary cortisol predict poorer memory in children. Brain and Cognition. 2011; 77 (2):191–199. [ PubMed : 21855200 ]
• Vaillancourt T, Hymel S, McDougall P. The biological underpinnings of peer victimization: Understanding why and how the effects of bullying can last a lifetime. Theory Into Practice. 2013a; 52 (4):241–248.
• Vaillancourt T, Brittain HL, McDougall P, Duku E. Longitudinal links between childhood peer victimization, internalizing and externalizing problems, and academic functioning: Developmental cascades. Journal of Abnormal Child Psychology. 2013b; 41 (8):1203–1215. [ PubMed : 23907699 ]
• Vaillancourt T, Sanderson C, Arnold P, McDougall P. Handbook of Bullying Prevention: A Life Course Perspective. Bradshaw CP, editor. National Association of Social Workers Press; (The neurobiology of peer victimization: Longitudinal links to health, genetic risk, and epigenetic mechanisms). in press.
• van Dam DS, van der Ven E, Velthorst E, Selten JP, Morgan C, de Haan L. Childhood bullying and the association with psychosis in non-clinical and clinical samples: A review and meta-analysis. Psychological Medicine. 2012; 42 (12):2463–2474. [ PubMed : 22400714 ]
• van Geel M, Vedder P, Tanilon J. Relationship between peer victimization, cyberbullying, and suicide in children and adolescents. Journal of American Medical Association Pediatrics. 2014; 168 (5):435–442. [ PubMed : 24615300 ]
• van Geel M, Goemans A, Vedder PH. The relation between peer victimization and sleeping problems: A meta-analysis. Sleep Medicine Reviews. 2015; 27 :89–95. [ PubMed : 26140869 ]
• Vannucci M, Nocentini A, Mazzoni G, Menesini E. Recalling unpresented hostile words: False memories predictors of traditional and cyberbullying. European Journal of Developmental Psychology. 2012; 9 (2):182–194.
• VanZomeren-Dohm AA, Pitula CE, Koss KJ, Thomas K, Gunnar MR. FKBP5 moderation of depressive symptoms in peer victimized, post-institutionalized children. Psychoneuroendocrinology. 2015; 51 :426–430. [ PMC free article : PMC4268402 ] [ PubMed : 25462914 ]
• Veenstra R, Lindenberg S, Munniksma A, Dijkstra JK. The complex relation between bullying, victimization, acceptance, and rejection: Giving special attention to status, affection, and sex differences. Child Development. 2010; 81 (2):480–486. [ PubMed : 20438454 ]
• Viding E, Blair RJR, Moffitt TE, Plomin R. Evidence for substantial genetic risk for psychopathy in 7-year-olds. Journal of Child Psychology and Psychiatry. 2005; 46 (6):592–597. [ PubMed : 15877765 ]
• Vossekuil B, Fein RA, Reddy M, Borum R, Modzeleski W. The Final Report and Findings of the Safe School Initiative: Implications for the Prevention of the Safe School Initiative. Washington, DC: U.S. Secret Service and Department of Education; 2002.
• Weaver IC, Cervoni N, Champagne FA, D'Alessio AC, Sharma S, Seckl JR, Dymov S, Szyf M, Meaney MJ. Epigenetic programming by maternal behavior. Nature Neuroscience. 2004; 7 (8):847–854. [ PubMed : 15220929 ]
• Weiner B. An Attributional Theory of Motivation and Emotion. New York: Springer-Verlag; 1986.
• Whelan YM, Kretschmer T, Barker ED. MAOA, early experiences of harsh parenting, irritable opposition, and bullying–victimization: A moderated indirect-effects analysis. Merrill-Palmer Quarterly. 2014; 60 (2):217–237.
• Wilker S, Pfeiffer A, Kolassa S, Elbert T, Lingenfelder B, Ovuga E, Papassotiropoulos A, de Quervain D, Kolassa IT. The role of FKBP5 genotype in moderating long-term effectiveness of exposure-based psychotherapy for posttraumatic stress disorder. Translational Psychiatry. 2014; 4 (6):1–7. [ PMC free article : PMC4080328 ] [ PubMed : 24959896 ]
• Williams KD, Bernieri FJ, Faulkner SL, Gada-Jain N, Grahe JE. The Scarlet Letter Study: Five days of social ostracism. Journal of Personal & Interpersonal Loss. 2000; 5 (1):19–63.
• Wilson TD, Damiani M, Shelton N. Improving Academic Achievement: Impact of Psychological Factors on Education. Wilson TD, editor. San Diego, CA: Elsevier BV; 2002. pp. 89–108. (Improving the academic performance of college students with brief attributional interventions).
• Wolke D, Woods S, Bloomfield L, Karstadt L. Bullying involvement in primary school and common health problems. Archives of Disease in Childhood. 2001; 85 (3):197–201. [ PMC free article : PMC1718894 ] [ PubMed : 11517098 ]
• Wolke D, Lereya ST, Fisher H, Lewis G, Zammit S. Bullying in elementary school and psychotic experiences at 18 years: A longitudinal, population-based cohort study. Psychological Medicine. 2014; 44 (10):2199–2211. [ PubMed : 24342773 ]
• Yang GS, McLoyd VC. Do parenting and family characteristics moderate the relation between peer victimization and antisocial behavior? A 5-year longitudinal study. Social Development. 2015; 24 :748–765.
• Ybarra ML, Mitchell KJ, Wolak J, Finkelhor D. Examining characteristics and associated distress related to Internet harassment: Findings from the second Youth Internet Safety Survey. Pediatrics. 2006; 118 (4):e1169–e1177. [ PubMed : 17015505 ]

Somatization is “a syndrome of physical symptoms that are distressing and may not be fully explained by a known medical condition after appropriate investigation. In addition, the symptoms may be caused or exacerbated by anxiety, depression, and interpersonal conflicts, and it is common for somatization, depression, and anxiety to all occur together” ( Greenberg, 2016 ).

Consolidation of memory is a biological process where the information one learns is stabilized within neural circuits and placed into long-term memory through a complex orchestration of molecular-level change and gene activation within neurons.

Peer victimization was measured with a 21-item revised version of the Social Experiences Questionnaire. The measure assesses overt and relational victimization and frequency of different acts of victimization ( Rudolph et al., 2016 ).

Reijntjes and colleagues (2010, p. 244) defined peer victimization as taking “various forms, including direct bullying behaviors (e.g., teasing, physical aggression) as well as more indirect manifestations such as group exclusion or malicious gossip.” Hawker and Boulton (2000, p. 441) defined peer victimization as “the experience among children of being a target of the aggressive behavior of other children, who are not siblings and not necessarily age-mates.”

Peer victimization was measured using peer, self-, and teacher reports, including peer nominations, a four-item self-report victimization scale, and a six-item teacher report victimization scale ( Kochel et al., 2012 ).

Stapinski et al. (2014) used a modified version of the Bullying and Friendship Interview Schedule to assess self-reported peer victimization. This measure includes items on overt victimization, such as threats, physical violence, and relational victimization.

Nonclinical psychotic symptoms are symptoms that do not meet the clinical definition for those psychotic disorders associated with such symptoms.

Peer victimization was measured using a modified six-item version of the Peer Victimization Scale, which asks students to select a statement that is most like them. Higher scores indicated higher levels of peer victimization ( Juvonen et al., 2011 ).

Peer victimization was measured using a 16-item peer nomination interview and a teacher-completed Social Behavior Rating Scale ( Schwartz et al., 2005 ).

Peer victimization is used here to include the broader category of bullying, peer victimization, and bullying behavior.

Psychotic experiences included hallucinations (visual and auditory), delusions (spied on, persecution, thoughts read, reference, control, grandiosity), and experiences of thought interference (broadcasting, insertion, and withdrawal), and any unspecified delusions.

This section is adapted from Rose (2015 , pp. 18-21).

A telomere is the “segment at the end of each chromosome arm which consists of a series of repeated DNA sequences that regulate chromosomal replication at each cell division.” See http://ghr ​.nlm.nih.gov/glossary=telomere [December 2015]. Telomeres are associated with “chromosomal stability” and the regulation of “cells' cellular replicative lifespan” (Kiecolt-Glaser et al., 2011, p. 16).

Peer victimization was measured by a teacher-reported seven-item measure with items measuring broader peer victimization (Hanish et al., 2004).

Peer victimization was measured using the Revised Peer Experiences Questionnaire, which assesses overt, relational, and reputational victimization by peers (McLaughlin et al., 2009).

High risk was defined as a mother who had her first child at age 20 or younger ( Moffitt, 2002 ).

Peer victimization was assessed through teacher, peer, and self-ratings. Children were asked to circle photographs of two classmates who get called names by other children and who are often pushed or hit by other children.

An allele is an alternate form of the same gene. Except for the XY chromosomes in males, human chromosomes are paired, so a cell's genome usually has two alleles for each gene.

The MAOA genotype has been called the “warrior” gene because of its association with aggression in studies using surveys and observations ( McDermott et al., 2009 ).

Peer victimization was measured using a teacher-report 3-item scale that assessed relational victimization in the classroom ( Kretschmer et al., 2013 ).

The FKBP5 rs1360780 gene is associated with a number of different psychological disorders ( Wilker et al., 2014 ).

VanZomeren-Dohm and colleagues (2015 measured peer victimization using the MacArthur Health and Behavior Questionnaire Parent-Form, version 2.1, in which parents reported on their children's experiences of overt peer victimization.

DNA methylation is a heritable epigenetic mark involving the covalent transfer of a methyl group to the C-5 position of the cytosine ring by DNA methyltransferases (a family of enzymes that act on DNA). Cytosine is one of the four bases that occur in varying sequences to form the “code” carried by strands of DNA ( Robertson, 2005 ).

Exposure to violence included domestic violence, bullying victimization, and physical abuse by an adult.

Cumulative violence exposure was measured by an index that summed each type of violence exposure.

• Cite this Page Committee on the Biological and Psychosocial Effects of Peer Victimization: Lessons for Bullying Prevention; Board on Children, Youth, and Families; Committee on Law and Justice; Division of Behavioral and Social Sciences and Education; Health and Medicine Division; National Academies of Sciences, Engineering, and Medicine; Rivara F, Le Menestrel S, editors. Preventing Bullying Through Science, Policy, and Practice. Washington (DC): National Academies Press (US); 2016 Sep 14. 4, Consequences of Bullying Behavior.
• PDF version of this title (3.8M)

In this Page

• MULTIPLE EXPOSURES TO VIOLENCE

Other titles in this collection

• The National Academies Collection: Reports funded by National Institutes of Health

Related information

• PMC PubMed Central citations
• PubMed Links to PubMed

Recent Activity

• Consequences of Bullying Behavior - Preventing Bullying Through Science, Policy,... Consequences of Bullying Behavior - Preventing Bullying Through Science, Policy, and Practice

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

Connect with NLM

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894

Web Policies FOIA HHS Vulnerability Disclosure

Help Accessibility Careers

To revisit this article, visit My Profile, then View saved stories .

• Backchannel
• Newsletters
• WIRED Insider
• WIRED Consulting

Steven Levy

There's No Undoing Tech's Great Rewiring of Childhood

The book currently topping the New York Times nonfiction bestseller list is The Anxious Generation , a jeremiad against social media and its impact on young people. Its thesis is that apps like Facebook, Instagram, and TikTok have unleashed an epidemic of mental illness among children, preteens, and teenagers. Immediate and extreme measures are required to reverse this deadly trend. The author, NYU social psychologist Jonathan Haidt, has been promoting it everywhere. Parents have rallied around his thesis, and Haidt’s claims have thrown gasoline on a smoldering movement to pass new laws to limit social media. But a review in Nature , one of the world’s most prestigious scientific journals, hit a more critical note. “The book’s repeated suggestion that digital technologies are rewiring our children’s brain and causing an epidemic of mental illness,” wrote Candice L. Odgers, a professor of psychological science at UC Irvine, “is not supported by science.”

This academic tiff has real consequences—think of the kids! When I contacted Odgers for more background, she was happy to oblige. She and her academic peers seem to view the massive public embrace of Haidt’s book as a slow-motion horror show. “I’ve been researching adolescent mental health for 20 years, and then actually tracking young adolescents, 10 to 14 years old, on their phones since 2008,” she says. “So I'm kind of old in this game. He's new.” Odgers says that the consensus of the community that actually studies this stuff for a living is that there is no evidence of Haidt’s claims that social media has triggered a mental health epidemic among a generation whose brains were scrambled by swiping on smartphones. She pointed me to a number of studies, including one 2022 meta-analysis of 226 studies involving 275,728 participants. “The association between social media use and well-being was indistinguishable from zero,” she and her coauthor reported. A study completed last year b y the National Academy of Sciences concluded there was not enough evidence to link social media with changes in adolescent health. (It asks for more research, measures to minimize any harm by social media, and also steps to maximize its benefit.)

Odgers and a colleague did find some studies that indicated there might be health effects of social media, but when they looked into it those experiments weren’t necessarily directed at kids. “Participants were often middle-aged women recruited online or small samples of college students who were asked to give up social media and report how they feel,” Odgers and her collaborator wrote in an article entitled “Let’s Stop Shaming Teens About Social Media Use.” Her bottom line is that while there is indeed a troubling rise in mental health issues among young people, especially girls, nothing beyond a nostalgia-tinged gut reaction indicates that social media is to blame.

When I laid this out to Haidt himself in a phone interview, he was well prepared. He describes the pushback against his work as “a normal academic dispute.” To his credit he has engaged with some of the criticism in his Substack posts . He’s not planning a retreat from his thesis. “I’m not going to convince them, and they're not going to convince me,” he says. “We each make our best arguments, and then the rest of the academic community will tune in and decide if there’s evidence of harm here.”

One of Haidt's strongest arguments is that it seems obvious how social media would play a role in the rise in mental health issues, even if other causes are just as likely. “We can say with confidence that teenagers are susceptible to the moods and beliefs of other teenagers—it’s been true forever,” he says. “We can also say that girls are more so than boys; they share each other's emotions more. So the idea that girls are picking up depression and anxiety from other girls I think is not controversial. The question is: What else are they picking up? And we don't know. Nobody knows.”

It would help if we did know. This argument matters in part because legislators and regulators in the US, EU, and UK are considering restrictions on how—and whether—minors access social media. It would make some sense if the threat was determined or debated on solid scientific ground. In the US, the leading potential bill is The Kids Online Safety Act, (Kosa) . A majority of the Senate has endorsed this draft law, but some civil liberties and free speech organizations think the bill goes too far. After objections from LGBTQ+ organizations that the bill would deny young people access to resources, its authors made rewrites to mitigate that danger. But critics feel that the bill still will provide too much authority for state and local officials to censor content on social media in the name of protecting children. A different bill would outright ban social media to everyone under 13, though some worry that if it were passed, stealthy apps would appear that offer even fewer protections than mainstream ones do now.

Putting the correlation-versus-causation issue aside, some of Haidt’s critiques of social media directed at kids seem beyond dispute. Meta’s own studies show that Instagram can have a negative effect on teen girls. It’s also clear that companies like Meta—which owns Instagram and Facebook—have not done enough to protect kids. During Mark Zuckerberg’s painful appearance at a Senate hearing last January—the one where the Meta CEO choked out regret to parents whose kids committed suicide after interactions on his platform—Senator Richard Blumenthal revealed a damning chain of 2021 emails . Meta’s top executives, including then-vice president of global affairs Nick Clegg, chief product officer Chris Cox, and then-chief operating officer Sheryl Sandberg, pleaded for more resources to address child safety and well being, laying out detailed plans that included more employees working on the problem. But Zuckerberg nixed the plan, basically because he didn’t want to spend the money. (Meta spokesperson Andy Stone says that the company has developed more than 50 tools to help teens have safe experiences.)

Will Knight

Scott Gilbertson

Brendan I. Koerner

But while Haidt harshly criticizes the inaction and greed of tech companies, he places most of the onus on the technology itself. He classifies social media as inherently evil like booze, cigarettes, and automatic rifles. That’s a harsh conclusion, especially if there’s only shaky evidence, or no evidence at all, that those apps are the key driver in kids’ mental health struggles. Especially since, unlike nicotine, liquor, and AR-15s, those apps have tangible benefits to young people.

Yes, some kids suffer because social media exposes them to bullies, makes them hate their bodies, or exposes them to unhealthy advertising. But one might argue it’s easier to find evidence that social media in the aggregate benefits youths more than it harms them. A sweeping US Centers for Disease Control study found that during the pandemic, there was indeed a mental health crisis among adolescents, and alarming rates of suicide. But social media could sometimes mitigate those problems. The study found that the bullying that kids suffered was less likely coming from their peers on Instagram than within their own families. And social media actually helped those kids: “Youth who felt more connected to people at their schools had better mental health,” wrote the CDC in a summary page, in a section called “ Connectedness Protects Youth .”

Haidt gives short shrift to the idea that social media has benefits. Intentionally or not, his arguments could lead to kids getting less useful information relevant to their lives. “He generally centers technology as the greatest cause of all the problems of young people, which is not accurate,” said technosocial scholar danah boyd, founder of the Data & Society research nonprofit, on a recent podcast . “It’s a really successful thing because it feeds into parents’ anxieties.”

Taylor Lorenz, the Washington Post reporter covering social media and author of the recent book Extremely Online , says that Haidt’s arguments are toxic. “It’s harmful because, as so many LGBTQ+ groups and others have made it very clear, social media is a lifeline for millions and millions of people,” she says. “And the notion that screen time is inherently bad is also a regressive idea. The same arguments that he uses are the ones that people once used for banning comic books, the radio, and all new forms of media.”

Haidt himself does say that social media isn’t the only thing that thwarts normal development for young people. The other trend among the young he bemoans is how overprotective parenting has cut down on IRL interactions, a phenomenon he addressed in his previous book, The Coddling of the American Mind . At one point in his new book, Haidt expresses unhappiness that hospitals aren’t seeing as many boys show up with shattered limbs, because it means that young males aren’t bulking up with the requisite toughness that will stand them in good stead during adulthood. He seems to idealize the Leave It to Beaver -style aimless hangouts of an earlier era, taking for granted that it’s a superior environment than the online one where people might make friends from anywhere in the world but not fall out of trees with them. I’m not so sure: I grew up way before social media and can attest that bullying in the real world was pervasive long before the internet showed up. At least on the internet, you don’t get punched in the face.

Like it or not, being digitally connected is the reality of the 21st century. This clock can’t be rolled back, and whatever comes after smartphones is going to make us even more connected. It’s unrealistic to treat digital life—aka just life —like an NC-17 movie that screens kids at the box office. Of course, we should demand that children be safe in this realm, as in any other, and I agree with Haidt that it’s a good idea to ban phones during school hours. But something big is afoot that affects all of humanity, and we have voted with our finger-swipes that it’s something we want.

“We're not going to stop the great rewiring of humanity,” Haidt concedes when I present him with that argument. “But it's an open question: Is this harmful to children?” The scientific community appears to be less sure, given the evidence cited by Odgers suggesting that the mental health crisis among kids has other causes. And for Haidt, the question seems already closed—his book screams that kids are being ruined. “I see no sign that kids can make it through this rewiring when we take away normal human childhood and give them a rewired child,” he tells me. He’d better look harder for those signs, because in 2024, “a normal childhood” now involves technology and social media. We could and should make it safer and less exploitative. We must demand that the platforms do better. But there’s no walking back the march of digital connection.

Time Travel

Almost 30 years ago, as the internet was finding its way into our lives, the media started writing stories about “internet addiction.” Like Jonathan Haidt’s current campaign against social media, it put a scientific sheen on some actual problem exacerbated by technology, while deemphasizing the value people extracted from online activity. I wrote about it for Newsweek in December 1996, in an article headlined “Breathing Is Also Addictive.”

The article in The New York Times painted a horrifying picture. A 17-year-old boy in a Texas rehab center, alternatively convulsing and throwing furniture around the room. “Had he been hooked on heroin?” the writer breathlessly asked. “Cocaine? Jim Beam? Joe Camel?” No. This was a victim of the latest dark cohort of that addictive cabal: the Internet. Another poor bastard hooked on cyberspace. And he's just the tip of the iceberg, the Times told us. Watch out for an epidemic of Net junkies. Moms who Net-surf while doe-eyed babes go hungry. Geeky high-school students up until 4 a.m., assuming studly personae in multiplayer dungeon games. Broken homes, broken jobs, broken lives ... the Days of Wine and Modems! All because of that Demon Net.

The problem with that article, and dozens like it that ran in 1996, is that "Internet addiction'' doesn't really exist. This disconnect between reality and reporting was symbolic of the general media's inability to convey the boggling changes that society is about to undergo, all because of our impending connectedness. The media declared 1995 the Year of the Internet; in '96, we tried to explain it to you. The measure of our success, sadly, may one day be judged by the Internet-addiction scare.

For starters, the term was coined as a joke by New York City psychiatrist Ivan Goldberg, who was astonished that people took him seriously. “There ain't no such thing!” he would howl to journalists, who wrote their stories anyway. Yes, it is true that many people use the Internet for hours on end; and, yes, it is true that a small percentage of those people go overboard, preferring the companionship of their online buddies to whining kids, demanding spouses and tedious responsibilities in the so-called “meat world.”

But these people aren't addicted, certainly not in the way that alcohol, drugs or cigarettes cause a measurably physical craving. Nor can you compare the Net's lure to gambling and overeating fixations: those are destructive activities, and the Net is not. “Using the Internet,” writes psychologist Storm A. King, “is no more inherently addicting than any other human activity that someone might find pleasure-producing, valuable, or productive.”

Ask Me One Thing

Tom asks, “The internet is outraged about a new Apple ad called “ Crush! ” in which musical instruments and other creative objects and materials are squashed by a giant machine and emerge as a brand-new iPad Pro. What do you think of it?”

Thanks, Tom. Apple has been a laggard among elite tech companies in generative AI. Though artificial intelligence has long been baked into Apple’s products and services, the company’s dramatic full-body embrace into tech’s most vital and disruptive sector apparently won't happen until next month’s developer conference, WWDC. This has somewhat insulated Apple from the growing unease about how AI will dehumanize our products, services, jobs, and even humans. As a result, it unwittingly made a one-minute video that triggered an artistic community already outraged by AI’s incursion on its turf. Microsoft, OpenAI, or Google never would have made this ad, because its leaders would have understood the implications in a second.

That’s the only explanation I can see for an ad that fetishizes the destruction of beloved instruments of human creativity. For those who haven’t viewed it, the commercial shows an industrial crush machine flattening musical instruments, video consoles, televisions, turntables, books, paints, and other beloved items with the enthusiasm of an action film glamorizing a car wreck. It’s like a snuff film where art itself is lasciviously murdered. The ostensible message is that all the wonderful songs, movies, video games, and books created with the artifacts of analog are now preserved in a gorgeous sliver of glass and aluminum of the new iPad Pro, which is all that remains when the brutal pancaking is complete. But that signal is overwhelmed by the prurient noise of destruction.

Instead of an ad for a cool new hardware product, Apple has minted a visible parable embodying the fears that AI will eliminate humanity’s purest expressions. It’s easily the biggest Apple ad blunder since “Lemmings” in 1985, which idiotically attempted to woo IBM customers by implying they were dull, brainsnatched droids. It’s also traumatic to inflict this carnage on a public that has yet to process the South Dakota governor’s boast that she murdered a 14-month-old puppy. Watching an acoustic guitar being crushed is sort of equivalent when it comes to fears that AI will supplant artists.

But here’s evidence that creativity still rules—one clever video artist fixed the problem by running the ad in reverse. Instead of unintentionally proclaiming the end of human creativity, the rewind version starts with the iPad and shows how within its wispy profile all the tools of genius reside therein. Tim Cook would do well to reward that creator and run the reverse version of the ad immediately in the original’s place. One also hopes this experience will incentivize Apple to approach the age of AI with more humility. We’ll find out next month.

You can submit questions to [email protected] . Write ASK LEVY in the subject line.

End Times Chronicle

Tornado-mania breaks out—just as the cicada invasion begins , with Illinois the epicenter of an unholy merger of two massive and destructive breeds. Who said life is boring between the coasts?

Last but Not Least

Elon Musk’s Neuralink’s technology is still in the brain of its first experimental patient. But not all is well .

After solving the very hard problem of protein folding with AlphaFold, DeepMind is now using its AI technology to model DNA .

An interview with a representative of the hacking group Cyber Army of Russia was bound to be strange. And it is.

Black Twitter was glorious . Fortunately its highlights are preserved in a terrific documentary, based on WIRED reporting, that you can view on Hulu .

You Might Also Like …

In your inbox: Will Knight's Fast Forward explores advances in AI

He emptied a crypto exchange onto a thumb drive —then disappeared

The real-time deepfake romance scams have arrived

Boomergasms are booming

Heading outdoors? Here are the best sleeping bags for every adventure

Morgan Meaker

Vittoria Elliott

Matthew Hutson

Lydia Morrish

Matt Burgess

Joel Khalili

Paresh Dave

• Election 2024
• Entertainment
• Newsletters
• Photography
• Personal Finance
• AP Investigations
• AP Buyline Personal Finance
• AP Buyline Shopping
• Press Releases
• Israel-Hamas War
• Russia-Ukraine War
• Global elections
• Asia Pacific
• Latin America
• Middle East
• Election Results
• Delegate Tracker
• AP & Elections
• Auto Racing
• 2024 Paris Olympic Games
• Movie reviews
• Book reviews
• Personal finance
• Financial Markets
• Business Highlights
• Financial wellness
• Artificial Intelligence
• Social Media

Biden hikes tariffs on Chinese EVs, solar cells, steel, aluminum — and snipes at Trump

President Joe Biden slapped major new tariffs on Chinese electric vehicles, advanced batteries, steel, aluminum and other goods Tuesday as he embraced a strategy that’s increasing friction between the world’s two largest economies.

President Joe Biden sits down to sign a document in the Rose Garden of the White House in Washington, Tuesday, May 14, 2024, imposing major new tariffs on electric vehicles, semiconductors, solar equipment and medical supplies imported from China. (AP Photo/Susan Walsh)

• Copy Link copied

President Joe Biden speaks in the Rose Garden of the White House in Washington, Tuesday, May 14, 2024, announcing plans to impose major new tariffs on electric vehicles, semiconductors, solar equipment and medical supplies imported from China. (AP Photo/Susan Walsh)

FILE - A worker assembles an SUV at a car plant of Li Auto, a major Chinese EV maker, in Changzhou in eastern China’s Jiangsu province on March 27, 2024. The Biden administration is announcing plans to slap new tariffs on Chinese electric vehicles, advanced batteries, solar cells, steel, aluminum and medical equipment. (Chinatopix Via AP, File)

WASHINGTON (AP) — President Joe Biden slapped major new tariffs on Chinese electric vehicles, advanced batteries, solar cells, steel, aluminum and medical equipment on Tuesday, taking potshots at Donald Trump along the way as he embraced a strategy that’s increasing friction between the world’s two largest economies.

The Democratic president said that Chinese government subsidies ensure the nation’s companies don’t have to turn a profit, giving them an unfair advantage in global trade.

“American workers can outwork and outcompete anyone as long as the competition is fair,” Biden said in the White House Rose Garden. “But for too long, it hasn’t been fair. For years, the Chinese government has poured state money into Chinese companies ... it’s not competition, it’s cheating.”

The tariffs come in the middle of a heated campaign between Biden and Trump, his Republican predecessor, to show who’s tougher on China. In a nod to the presidential campaign, Biden recognized lawmakers from Michigan in his remarks and spoke about workers in Pennsylvania and Wisconsin, all battleground states in November’s election.

Asked to respond to Trump’s comments that China was eating America’s lunch, Biden said of his rival, “He’s been feeding them a long time.” The Democrat said Trump had failed to crack down on Chinese trade abuses as he had pledged he would do during his presidency.

Karoline Leavitt, the Trump campaign’s press secretary, called the new tariffs a “weak and futile attempt” to distract from Biden’s own support for EVs in the United States, which Trump says will lead to layoffs at auto factories.

The Chinese government was quick to push back against the tariffs, saying they “will seriously affect the atmosphere of bilateral cooperation.” The foreign ministry used the word “bullying.”

The tariffs are unlikely to have a broad inflationary impact in the short term because of how they’re structured, some not to take effect until 2026, but there could be price increases in the meantime for EV batteries, solar and some other specific items.

Biden administration officials said they think the tariffs won’t escalate tensions with China, yet they expect China will explore ways to respond to the new taxes on its products. It’s uncertain what the long-term impact on prices could be if the tariffs contribute to a wider trade dispute.

The tariffs are to be phased in over the next three years, with those that take effect in 2024 covering EVs, solar cells, syringes, needles, steel and aluminum and more. There are currently very few EVs from China in the U.S., but officials worry low-priced models made possible by Chinese government subsidies could soon start flooding the U.S. market.

Chinese firms can sell EVs for as little as $12,000 . China’s solar cell plants and steel and aluminum mills have enough capacity to meet much of the world’s demand, with Chinese officials arguing their production keeps prices low and would aid a transition to the green economy.

China’s commerce ministry said in a statement that the tariffs were “typical political manipulation” as it expressed its “strong dissatisfaction” and pledged to “take resolute measures to defend its rights and interests.”

Under the findings of a four-year review on trade with China, the tax rate on imported Chinese EVs will rise to 102.5% this year, up from total levels of 27.5%. The review was undertaken under Section 301 of the Trade Act of 1974, which allows the government to retaliate against trade practices deemed unfair or in violation of global standards.

Under the 301 guidelines, the tariff rate is to double to 50% on solar cell imports this year. Tariffs on certain Chinese steel and aluminum products will climb to 25% this year. Computer chip tariffs will double to 50% by 2025.

For lithium-ion EV batteries, tariffs will rise from 7.5% to 25% this year. But for non-EV batteries of the same type, the tariff increase will be implemented in 2026. There are also higher tariffs on ship-to-shore cranes, critical minerals and medical products.

The new tariffs, at least initially, are largely symbolic since they will apply to only about $18 billion in imports. A new analysis by Oxford Economics estimates the tariffs will have a barely noticeable impact on inflation by pushing up inflation by just 0.01%.

The Chinese EV maker BYD has explored the possibility of opening factories in Mexico for the Mexican market, possibly creating a way to ship goods into the United States. U.S. Trade Representative Katherine Tai said she was talking with industry and workers about the possibility and to “stay tuned.”

The auto industry is still trying to assess the impact of the tariffs. But at present, it appears they could be assessed on only two Chinese-made vehicles, the Polestar 2 luxury EV and potentially Volvo’s S90 luxury gas-electric hybrid midsize sedan.

“We’re still reviewing the tariffs to understand exactly what’s affected and how,” said Russell Datz, spokesman for Volvo, a Swedish brand now under China’s Geely group. A message was left seeking comment from Polestar, which also falls under Geely.

The Chinese foreign ministry spokesperson, Wang Wenbin, said the U.S. is trampling on the principles of a market economy and international economic and trade rules.

“It’s a naked act of bullying,” Wang said.

The Chinese economy has been slowed by the collapse of the country’s real estate market and past coronavirus pandemic lockdowns, prompting Chinese President Xi Jinping to try to jumpstart growth by ramping up production of EVs and other products, making more than the Chinese market can absorb.

This strategy further exacerbates tensions with a U.S. government that claims it’s determined to strengthen its own manufacturing to compete with China, yet avoid a larger conflict.

“China’s factory-led recovery and weak consumption growth, which are translating into excess capacity and an aggressive search for foreign markets, in tandem with the looming U.S. election season add up to a perfect recipe for escalating U.S. trade fractions with China,’’ said Eswar Prasad, professor of trade policy at Cornell University.

The Europeans are worried, too. The EU launched an investigation last fall into Chinese subsidies and could impose an import tax on Chinese EVs.

After Xi’s visit to France last week, European Commission President Ursula von der Leyen warned that government-subsidized Chinese EVs and steel “are flooding the European market” and said, “The world cannot absorb China’s surplus production.’’

Biden’s administration views China, with its subsidies of manufacturing, as trying to globally control the EV and clean-energy sectors, whereas the administration says its own industrial support is geared toward ensuring domestic supplies to help meet U.S. demand.

“We do not seek to have global domination of manufacturing in these sectors, but we believe because these are strategic industries and for the sake of resilience of our supply chains, that we want to make sure that we have healthy and active firms,” Treasury Secretary Janet Yellen said.

The tensions go far beyond a trade dispute to deeper questions about who leads the world economy as a seemingly indispensable nation. China’s policies could make the world more dependent on its factories, possibly giving it greater leverage in geopolitics. At the same time, the United States says it’s seeking for countries to operate by the same standards so competition can be fair.

China maintains the tariffs are in violation of the global trade rules the United States originally helped establish through the World Trade Organization. It accuses the U.S. of continuing to politicize trade issues and on Friday said the new tariffs compound the problems caused by tariffs the Trump administration previously put on Chinese goods, which Biden has kept.

Those issues are at the heart of November’s presidential election, with a bitterly divided electorate seemingly united by the idea of getting tough with China. Biden and Trump have overlapping but different strategies.

Biden sees targeted tariffs as needed to defend key industries and workers, while Trump has threatened broad 10% tariffs against all imports from rivals and allies alike.

Biden has staked his presidential legacy on the U.S. pulling ahead of China with its own government investments in factories to make EVs, computer chips and other advanced technologies.

Trump tells his supporters America is falling further behind China by not betting on oil to keep powering the economy, despite its climate change risks. The ex-president may believe tariffs can change Chinese behavior, but he believes the U.S. will be reliant on China for EV components and solar cells.

“Joe Biden’s economic plan is to make China rich and America poor,” he said at a rally this month in Wisconsin.

AP autos writer Tom Krisher contributed to this report from Detroit.