OBJECTIVES:To evaluate the effectiveness and safety of risperidone in children and adolescents with bipolar disorder characterized by aggression and mania, despite treatment with mood stabilizers. METHODS:A retrospective chart review of patients seen in an outpatient pediatric mood disorders clinic over an 18-month period was performed. Data were extracted from charts of patients who had a diagnosis of bipolar disorder with aggression that was uncontrolled on a mood stabilizer; as a result, these patients had risperidone added to their regimen. RESULTS:Four boys (aged 7-15 years) and two girls (aged 8 and 14 years) were treated with risperidone (mean dosage, 0.85 mg/day) for 3-16 months. Aggressive behavior improved in all patients after risperidone was started and remained improved for the duration of follow-up. Other symptoms of mania also improved. Risperidone was generally well tolerated. Sedation and akathisia were reported in one patient. CONCLUSIONS:The addition of risperidone to a mood stabilizer may improve aggression and other symptoms of mania in pediatric patients with bipolar disorder who do not respond adequately to a mood stabilizer alone. The long-term efficacy and safety of this regimen should be evaluated in a controlled clinical trial.