• OBJECTIVE
    • This article addresses the following questions: What are the best demographic and psychiatric predictors of the onset of conduct disorder (CD)? Does physical fighting play a role in the transition from oppositional defiant disorder (ODD) to CD? And what are the predictors of an earlier compared with a later onset of CD?
  • METHOD
    • Data are presented on the follow-up of a clinic-referred sample of 177 preadolescent boys who were studied for a period of 6 years. Psychiatric assessments were based on information from the boys, their parent, and their teacher.
  • RESULTS
    • Of all CD symptoms, physical fighting best predicted the onset of CD in bivariate analyses. Logistic regression showed that low socioeconomic status of the parent, ODD, and parental substance abuse best predicted the onset of CD. In addition, attention-deficit hyperactivity disorder (ADHD) predicted an early onset of CD.
  • CONCLUSIONS
    • Parental substance abuse, low socioeconomic status, and oppositional behavior are key factors in boys' progression to CD. Physical fighting, although not a symptom of ODD, should be targeted in preventive interventions along with ODD symptoms. ADHD is implicated in the early onset of CD, but not in later-onset CD.