Risperidone effects in the presence/absence of psychostimulant medicine in children with ADHD, other disruptive behavior disorders, and subaverage IQ.

Objective: The aim of this study was to examine the safety and efficacy of risperidone, with or without concomitant psychostimulant use, in the treatment of children with conduct disorder (CD) or other disruptive behavior disorders [oppositional defiant disorder (ODD), disruptive behavior disorder-not otherwise specified (DBD-NOS)], and comorbid attention-deficit hyperactivity disorder (ADHD).

Methods: Data from two 6-week placebo-controlled trials assessing risperidone therapy in children with subaverage IQs and CD, ODD, DBD-NOS were combined, and patients with comorbid ADHD were selected for this post hoc analysis. Patients were grouped according to randomized drug therapy (risperidone or placebo), and then subgrouped according to their use of a concomitant psychostimulant. Safety outcomes included adverse events and weight change, while efficacy outcomes included changes in scores on disruptive behavior and hyperactivity-based subscales of two behavior-rating instruments (Nisonger Child Behavior Rating Form and the Aberrant Behavior Checklist).

Results: The analysis included 155 of 208 originally tested children divided into four sub-groups (35-43 patients each). There was no significant difference in the frequency of adverse events in patients who received risperidone alone and those who received risperidone plus a stimulant. The most common adverse events in risperidone-treated patients were somnolence, headache, dyspepsia, rhinitis, and vomiting. Within each randomized treatment group, actual weight gain was comparable, regardless of concomitant stimulant use. Risperidone-treated patients had clinically and statistically significant reductions in both disruptive behavior and hyperactivity subscale scores, compared to placebo, regardless of concomitant stimulant use. The addition of risperidone to a psychostimulant resulted in significantly better control of hyperactivity (p < 0.001) than was achieved with stimulant treatment alone, without causing an increase in adverse events.

Conclusion: Risperidone was a safe and effective treatment, with or without a combined psychostimulant, for both disruptive behavior disorders and comorbid ADHD in children.