Abstract
Delinquency and conduct disorder have been predominantly ascribed to psychosocial influences. Data consistently confirm that offending behaviour in adolescents often occurs together with, or as an expression of substance abuse, mood disorders, ADHD and possibly psychosis. However the specific connections between offending and psychiatric symptoms remain to be elucidated. Research into genetic bases and biological markers of adolescent offending has begun to uncover the complicated interactions between nature and nurture.