Relation between childhood disruptive behavior disorders and substance use and dependence symptoms in young adulthood: Individuals with symptoms of attention-deficit/hyperactivity disorder are uniquely at risk.

Most prior literature examining the relations among attention-deficit/hyperactivity disorder (ADHD), conduct disorder (CD), and substance use and abuse suggests that CD fully account for the ADHD-substance abuse relation. This study sought to test an alternate theory that individuals with symptoms of both ADHD and CD are at a special risk for substance abuse. Relations between childhood ADHD and CD symptoms, and young adult tobacco, alcohol, marijuana, and hard drug use and dependence symptoms, were examined in a sample of 481 young adults. ADHD and CD symptoms interacted to predict marijuana dependence symptoms and hard drug use and dependence symptoms, such that individuals with high levels of both ADHD and CD had the highest levels of these outcomes.