OBJECTIVE: To examine the safety and efficacy of liquid risperidone to reduce duration of rages in children with severe mood dysregulation (SMD) or possible bipolar disorder (BP). METHOD: The sample included 151 consecutive admissions of 5-12 year old children to a psychiatric inpatient unit. Diagnostic information and history of prior rage outbursts were obtained at admission. In hospital, a first rage was treated with seclusion. If a second rage occurred, the child was offered liquid risperidone to help him/her regain control. Durations of unmedicated and last medicated rage were compared. Rage frequency in children with SMD and several definitions of BP were compared. RESULTS: Although 82 of 151 admissions were prompted by rages, rages occurred during only 49 hospitalizations and occurred more than once in only 24. In 16 multiply medicated children, duration of rages dropped from a baseline of 44.4 +/- 20.2 min to 25.6 +/- 12.5 min at the child's last dose. Neither SMD nor any definition of BP influenced rage response in this small sample. The average liquid risperidone dose was 0.02 mg/kg. All but two children also took atypical antipsychotics daily. In the evaluation of medicated rage episodes with standard rating scales, no extrapyramidal side effects, akathisia, or abnormal involuntary movements were observed, and the rate of sedation/sleepiness (7/67 = 10.4%) was similar and not significantly different from that observed during nonmedicated episodes (8/46 = 17.4%). CONCLUSIONS: Liquid risperidone may be a safe and effective way to shorten the duration of rage episodes regardless of diagnosis. However, definitive conclusions cannot be drawn in the absence of a placebo control as children were also receiving other behavioral and psychopharmacologic treatments.