Delinquency and aggression are common externalizing behaviors in adolescence and have been linked to internalizing symptoms such as depression and anxiety. However, evidence regarding these associations remains mixed. This study investigated whether depressive and anxiety symptoms are associated with delinquent and aggressive behavior, and whether these associations differ by sex, in a non-forensic, community-based adolescent sample. 

Data were drawn from 731 adolescents (46.4% male; mean age at baseline = 14.9) participating in the Dutch iBerry Study, with follow-up data collected at age 18. Internalizing symptoms were measured using the ASEBA system through multi-informant reports; externalizing outcomes were assessed using the Self-Reported Early Delinquency (SRED) and the Reactive-Proactive Aggression Questionnaire (RPQ).

Logistic regression analyses showed that depressive and anxiety symptoms were significantly associated with aggression in unadjusted models, but these associations were no longer significant after controlling for demographic and behavioral covariates. No associations were found between internalizing symptoms and delinquency or aggression subtypes (proactive/reactive), and no significant interaction effects with sex were observed.

These findings suggest that internalizing symptoms alone may not independently predict externalizing behavior when broader contextual factors are considered. The results highlight the importance of adopting a multifactorial approach and call for further longitudinal research to clarify the mechanisms linking mental health and behavioral outcomes in adolescence.