Clinical efficacy of methylphenidate in conduct disorder with and without attention deficit hyperactivity disorder.

Background: Stimulants are not considered appropriate for the treatment of children with conduct disorders (CDs). The postulated differences in stimulant effect between children with attention deficit hyperactivity disorder (ADHD) and CD led to the hypothesis that methylphenidate hydrochloride, which is effective in ADHD, would not significantly improve symptoms of CD.

Methods: We randomly assigned 84 children with CD, between the ages of 6 and 15 years, to receive methylphenidate hydrochloride (up to 60 mg/d) or placebo for 5 weeks. Behavior was evaluated by parent, teacher, and clinician reports and by direct classroom observations. Two thirds of the children also met criteria for ADHD.

Results: Contrary to prediction, ratings of antisocial behaviors specific to CD were significantly reduced by methylphenidate treatment. The magnitude of methylphenidate effect indicated meaningful clinical benefit. Partialling out severity of ADHD did not alter the significant superiority of methylphenidate on CD ratings specifically (P < .001).

Conclusions: Methylphenidate has short-term positive effects on children and adolescents with CD. Key aspects of antisocial adjustment appear to be treatment responsive. This effect was independent of severity of the children's initial ADHD symptoms.