Objective: The authors compared the effects of maintenance versus withdrawal of risperidone treatment in children and adolescents with symptoms of disruptive behavior disorder. Method: Patients with disruptive behavior disorder (5-17 years of age and a range of intellect) who had responded to risperidone treatment over 12 weeks were randomly assigned to 6 months of double-blind treatment with either risperidone or placebo. The primary efficacy measure was time to symptom recurrence, defined as sustained deterioration on either the Clinical Global Impression severity rating (÷2 points) or the conduct problem subscale of the Nisonger Child Behavior Rating Form (÷7 points). Secondary efficacy measures included rates of discontinuation due to symptom recurrence, disruptive behavior disorder symptoms, and general function. Safety and tolerability were also assessed. Risperidone dosage was based on weight (patients <50 kg: 0.25-0.75 mg/day; patients ÷50 kg: 0.5-1.5 mg/day). Results: Treatment was initiated in 527 patients, with 335 randomly assigned to a double-blind maintenance condition. Time to symptom recurrence was significantly longer in patients who continued risperidone treatment than in those switched to placebo. Symptom recurrence in 25% of patients occurred after 119 days with risperidone and 37 days with placebo. Secondary efficacy measures also favored risperidone over placebo. Weight increased over the initial 12 weeks of treatment (mean weight z score change=0.2, SD=2.7, N=511), after which it plateaued. Conclusions: This study is the first placebo-controlled maintenance versus withdrawal trial of its kind in disruptive behavior disorder and provides evidence that patients who respond to initial treatment with risperidone would benefit from continuous treatment over the longer term.