Bullying at school as a predictor of delinquency, violence and other anti-social behaviour in adulthood.

BACKGROUND Although bullying at school is an important topic, its long-term relation to anti-social development is rarely investigated. AIM To study the relation between bullying in youth and anti-social outcomes in adulthood. METHODS A group of 63 males (bullies and victims over-sampled) from the Erlangen-Nuremberg Bullying Study were investigated at ages 15 and 25. Bullying was assessed with the Olweus Bully/Victim Questionnaire. Outcome measures included self-reported delinquency, violence, aggressiveness, drug use, impulsivity and psychopathy. In addition to bivariate correlations, hierarchical regressions were used to control for family and individual risk factors. RESULTS Bullying was a strong predictor of nearly all anti-social outcomes. Physical bullying was more predictive than verbal/indirect bullying. Controlling for family risks and externalising/internalising problems reduced effect sizes, but bullying remained a sound predictor. Victimisation was not related to anti-social outcomes. CONCLUSIONS Bullying seems to be a key risk marker for anti-social development. Therefore, studies on whole-school anti-bullying programmes and child-oriented or family-oriented strategies of crime prevention should be more integrated.