Bullying at age eight and criminality in adulthood: findings from the Finnish Nationwide 1981 Birth Cohort Study

Context There are no prospective population-based studies examining predictive associations between childhood bullying behavior and adult criminality. Objective To study predictive associations between bullying and victimization at age eight and adult criminal offenses. Design Nationwide birth cohort study from age 8 to 26 years. Participants The sample consists of 5,351 Finnish children born in 1981 with information about bullying and victimization at age eight from parents, teachers, and the children themselves. Main outcome measures National police register information about criminal offenses at age 23–26 years. Results When controlled for the parental education level and psychopathology score, bullying sometimes and frequently independently predicted violent (OR 3.9, 95% CI 1.9–7.9, p\0.001; OR 2.5, 95% CI 1.6–4.1, p\0.001, respectively), property (OR 2.3, 95% CI 1.2–4.7, p\0.05; OR 1.7, 95% CI 1.1–2.7, p\0.05), and traffic (OR 2.8, 95% CI 1.8–4.4, p\0.001; OR 1.6, 95% CI 1.3–2.1, p\0.001) offenses. The strongest predictive association was between bullying frequently and more than five crimes during the 4-year period (OR 6.6, 95% CI 2.8–15.3, p\0.001) in adjusted analyses. When different informants were compared, teacher reports of bullying were the strongest predictor of adult criminality. In adjusted analyses, male victimization did not independently predict adult crime. Among girls, bullying or victimization at age eight were not associated with adult criminality. Conclusions Bullying among boys signals an elevated risk of adult criminality