Objective: To examine precursors of adolescent conduct disorder (CD) in children with attention-deficit/hyperactivity disorder (ADHD), examining the role of childhood oppositional defiant disorder (ODD) and ADHD. 

Method: The investigators evaluated 151 children with ADHD using standard diagnostic interviews at ages 6 to 13 years and 5 years later in adolescence. The subjects were recruited from child psychiatric and pediatric clinics. Multiple regression analysis was used to evaluate baseline ODD diagnosis and ODD, CD, and ADHD symptom scores as clinical predictors of adolescent CD diagnosis and symptom scores. 

Results: There was a significant association between childhood ODD (diagnosis and severity) and adolescent CD (diagnosis and severity). The association was independent of childhood ADHD severity and childhood CD. Children with a diagnosis of ODD were almost 3 times more likely to develop CD in adolescence (odds ratio = 2.79, 95% CI = 1.16 to 6.70, p = .02). Although there was a trend toward association, adolescent CD scores, but not diagnosis of CD, were predicted by the severity of childhood ADHD. Adolescent CD severity was predicted by the presence of at least 1 CD symptom in childhood. 

Conclusions: Regardless of ADHD severity, ODD is a significant precursor of adolescent CD in children with ADHD. Given that ADHD with comorbid CD has a poor prognosis, it is critical that clinicians be especially vigilant for childhood ODD behaviors.