Cross-informant agreement about bullying and victimization among eight-year-olds: whose information best predicts psychiatric caseness 10–15 years later

Objective To examine cross-informant agreement and whose information (parents, teachers, children) about childhood bullying and victimization carry the strongest weight to late adolescent psychiatric outcome. The importance of frequency of bullying in such predictions is addressed. Methods Information from 2,713 boys about bullying and victimization at the age of eight was correlated with information about psychiatric disorder at 18–23. Results Agreement between informants was poor. Teachers reported higher levels of frequent bullying than others, whereas children reported the highest percentage of victimization. All three informant groups’ reports of ‘‘frequent bullying’’ predicted later psychiatric disorder. Teachers’ reports of ‘‘frequent victimization’’ was the strongest predictor of later psychiatric disorder. Informants’ report about ‘‘infrequent bullying’’ showed at most a rather low risk of adverse outcome. When the associations between bullying/victimization and psychiatric outcome were adjusted with total psychopathology score at age 8, none of the associations remained significant. Conclusion ‘‘Frequent bullying’’ behaviour of boys is a marker of present and later psychopathology. The education system and school health-care service in mid- childhood are of great importance for the early detection of bullying and prevention of later adverse outcomes. A closer integration of these systems in the context of school should be promoted.