Adolescent peer aggression and its association with mental health and substance use in an Australian cohort.

Prospective longitudinal birth cohort data was used to examine the association between peer aggression at 14 years and mental health and substance use at 17 years. A sample of 1590 participants from the Western Australian Pregnancy Cohort (Raine) study were divided into mutually exclusive categories (victims, perpetrators, victim-perpetrators and uninvolved). Involvement in any type of peer aggression as a victim (10.1%), perpetrator (21.4%), or a victim-perpetrator (8.7%) was reported by 40.2% of participants. After adjusting for confounding factors, those who were a victim of peer aggression had increased odds of later depression and internalising symptoms whilst perpetrators of peer aggression were found to be at increased risk of depression and harmful alcohol use. Victim-perpetrators of peer aggression were more likely to have externalising behaviours at 17 years. These results show an independent temporal relationship between peer aggression and later mental health and substance use problems in adolescence.