Risperidone in the treatment of childhood autistic disorder: an open pilot study

Objective:To evaluate the tolerability and efficacy of risperidone in childhood autistic disorder.Methods:A multicenter, open-label, dose-titration study involving seven autistic children (mean age 7.6 years) receiving risperidone for 4 weeks.Results:Mean dose was 0.01 mg/kg/day on day 1, 0.019 mg/kg/day on day 7 (range 0.01–0.041 mg/kg/day) and 0.035 mg/kg/day on day 28 (range 0.014–0.064 mg/kg/day). Over the 4-week period, the Ritvo–Freeman Real Life Rating Scale total score measuring autistic behavior was significantly decreased (P = 0.019), as was the affectual reactions subscale (P = 0.029). Aberrant Behavior Checklist total score was significantly improved (P < 0.001), as were all subscales except inappropriate speech. Visual Analog Scale for individual target symptoms was significantly decreased (P = 0.001), and Clinical Global Impression severity of illness score was significantly improved (P = 0.006). The incidence of adverse effects was low, and no extrapyramidal symptoms were observed. No significant changes or clinically relevant abnormalities occurred in laboratory tests, vital signs or electrocardiograms. Plasma concentrations of the drug were similar to those in adult patients.Conclusions:These favorable results suggest that larger controlled trials of risperidone should be performed in autistic or mentally retarded patients with behavioral disturbances.