Interactive effects of attention deficit hyperactivity disorder and conduct disorder on early adolescent substance use.

This study examined the interactive effects of attention deficit hyperactivity disorder (ADHD) and conduct disorder (CD) diagnosis on early adolescent substance use in a cross-sectional study of 202 middle school students. ADHD diagnosis alone did not suggest increased risk for substance use, but more adolescents with both ADHD and CD reported use of tobacco, alcohol, marijuana, and other drugs than did adolescents with either disorder alone. Dimensionally scored impulsivity-hyperactivity symptoms, not symptoms of inattention, appeared to account for the association with ADHD. Results illustrate the need to continue examination of the role of ADHD in the development of substance use and later abuse, especially as it relates to the onset of conduct problems in adolescence that mark liability for early onset substance abuse.