CONTEXT: The causal relation between school bullying and psychopathologic behavior has been the focus of substantial debate. Previous studies have failed to garner causal evidence in either direction, largely because of methodologic constraints such as cross-sectional study designs, shared method variance, and analytic shortfalls. OBJECTIVE: To determine the direction of the causal relation between psychopathologic behavior and school bullying. DESIGN: Prospective cohort study. SETTING: Two Korean middle schools. PARTICIPANTS: A total of 1655 seventh- and eighth-grade students were studied between 2000 and 2001. MAIN OUTCOME MEASURES: School bullying was assessed by peer nomination, and 7 subscales of the Korean Youth Self Report were used to identify symptoms of psychopathologic behaviors. School bullying was categorized into 4 groups: victims, perpetrators, victim-perpetrators, and neither. A T-score on the Korean Youth Self Report greater than 65 was regarded as a clinically significant indicator. RESULTS: Social problems increased the risk of becoming a victim or a victim-perpetrator (odds ratio [OR], 2.3 and 2.7, respectively), and these associations disappeared when baseline bullying status was adjusted. Ten months later, individuals who were victims at baseline showed increased risk of social problems (OR, 3.9), those who were perpetrators had increased aggression (OR, 1.8), and victim-perpetrators had increased aggression and externalizing problems (OR, 4.9 and 4.6, respectively). Analyses that examined exposure history provided additional evidence for the causal effect of bullying experience on the later development of psychopathologic behaviors because most forms of psychopathologic behavior that led to new-onset bullying at follow-up were also present at follow-up, making it impossible to distinguish the temporal sequence of these variables and their causal relationship. However, most forms of new-onset psychopathologic behaviors at follow-up were associated with antecedent bullying experience. CONCLUSIONS: Our study results support the conclusion that psychopathologic behavior, including social problems, aggression, and externalizing behavioral problems, is a consequence rather than a cause of bullying experiences. This causal relation is supported by the strength and specificity of the association and the temporal antecedence of bullying. Because school bullying is a known correlate of youth violence, such a finding adds greater urgency to the search for programs to prevent or diminish bullying among schoolchildren.
CONTEXT: The causal relation between school bullying and psychopathologic behavior has been the focus of substantial debate. Previous studies have failed to garner causal evidence in either direction, largely because of methodologic constraints such as cross-sectional study designs, shared method variance, and analytic shortfalls. OBJECTIVE: To determine the direction of the causal relation between psychopathologic behavior and school bullying. DESIGN: Prospective cohort study. SETTING: Two Korean middle schools. PARTICIPANTS: A total of 1655 seventh- and eighth-grade students were studied between 2000 and 2001. MAIN OUTCOME MEASURES: School bullying was assessed by peer nomination, and 7 subscales of the Korean Youth Self Report were used to identify symptoms of psychopathologic behaviors. School bullying was categorized into 4 groups: victims, perpetrators, victim-perpetrators, and neither. A T-score on the Korean Youth Self Report greater than 65 was regarded as a clinically significant indicator. RESULTS: Social problems increased the risk of becoming a victim or a victim-perpetrator (odds ratio [OR], 2.3 and 2.7, respectively), and these associations disappeared when baseline bullying status was adjusted. Ten months later, individuals who were victims at baseline showed increased risk of social problems (OR, 3.9), those who were perpetrators had increased aggression (OR, 1.8), and victim-perpetrators had increased aggression and externalizing problems (OR, 4.9 and 4.6, respectively). Analyses that examined exposure history provided additional evidence for the causal effect of bullying experience on the later development of psychopathologic behaviors because most forms of psychopathologic behavior that led to new-onset bullying at follow-up were also present at follow-up, making it impossible to distinguish the temporal sequence of these variables and their causal relationship. However, most forms of new-onset psychopathologic behaviors at follow-up were associated with antecedent bullying experience. CONCLUSIONS: Our study results support the conclusion that psychopathologic behavior, including social problems, aggression, and externalizing behavioral problems, is a consequence rather than a cause of bullying experiences. This causal relation is supported by the strength and specificity of the association and the temporal antecedence of bullying. Because school bullying is a known correlate of youth violence, such a finding adds greater urgency to the search for programs to prevent or diminish bullying among schoolchildren.