Effectiveness and tolerability of switching to aripiprazole from risperidone in subjects with autism spectrum disorders: a prospective open-label study.

BACKGROUND: Subjects with autism spectrum disorders (ASDs) often exhibit behavioral symptoms such as aggressiveness and irritability. The purpose of this study was to examine the efficacy and the tolerability of aripiprazole switched from risperidone in children and adolescents with ASD.

METHODS: This prospective, 12-week, open-label study included 9 male subjects with ASD (age range, 9-22 years; mean ± SD age, 14.8 ± 4.0 years) followed up for 12 weeks after switching to aripiprazole from risperidone. The primary outcome measures were the Clinical Global Impression-Improvement scales and the irritability subscale of the Aberrant Behavior Checklist.

RESULTS: The mean ± SD maintenance dosages of risperidone and aripiprazole were 0.6 ± 0.4 mg/d and 4.8 ± 4.0 mg/d, respectively. The mean ± SD scores of the irritability subscale of the Aberrant Behavior Checklist before switching to aripiprazole (baseline) and 12 weeks after switching to aripiprazole (end point) were 14.8 ± 7.6 and 13.1 ± 8.0, respectively. The mean ± SD Clinical Global Impression-Improvement score, a comparison from baseline to end point, was 2.4 ± 0.7. Mild somnolence was observed only in 1 subject. No significant changes in vital signs, weight, electrocardiogram, or laboratory measures occurred during switching to aripiprazole. Serum prolactin levels decreased significantly from 17.3 ± 9.4 ng/mL (baseline) to 2.3 ± 1.7 ng/mL (end point).

CONCLUSIONS: The results show that aripiprazole might be generally well tolerated and might constitute an alternative treatment of subjects with ASD who experience poor efficacy or tolerability issues with risperidone treatment. Additional long-term controlled studies are needed to evaluate the efficacy and the safety of switching to aripiprazole from other antipsychotics in subjects with ASD.