Risperidone treatment in children and adolescents with autism: short- and long-term safety and effectiveness.

Objective: Atypical neuroleptics, including risperidone, are used to treat children with autism, despite limited efficacy and safety data. Many clinicians believe that risperidone will not induce dyskinesias in children. The authors investigated open risperidone treatment in children with autism and included findings on dyskinesias.

Method: The sample included 22 outpatients (mean age = 7.1 years) diagnosed with autism (DSM-IV). Treatment consisted of a 1-month short-term phase followed by a 6-month long-term phase. At the end of the long-term phase, drug was discontinued, and the need for further drug treatment and the occurrence of withdrawal dyskinesias were assessed. Measures included the Clinical Global Impressions (CGI), Children's Psychiatric Rating Scale (CPRS), and the Abnormal Involuntary Movement Scale.

Results: The mean risperidone dosage was 1.2 mg/day. Overall, the children had significant clinical improvement as assessed by the CPRS and CGI. Untoward effects included sedation, increased appetite, and weight gain. Two of 13 (15.4%) children treated long-term developed mild, reversible withdrawal dyskinesias when risperidone was discontinued. No child developed dyskinesias on risperidone.

Conclusions: Risperidone shows promise as a treatment in autism. However, withdrawal dyskinesias were noted. Further assessment of the risk of risperidone-related dyskinesias is indicated.