Effects of risperidone on core symptoms of autistic disorder based on childhood autism rating scale: an open label study.

Background: The aim of the present study was to evaluate the effect of risperidone in patients afflicted by autistic disorder especially with regards to its three core symptoms, including "relating to others", "communication skills", and "stereotyped behaviors" based on Childhood Autism Rating Scale (CARS).

Materials And Methods: An 8-week open-label study of risperidone for treatment of autistic disorder in children 4-17 years old was designed. Risperidone dose titration was as follow: 0.02 mg/kg/day at the first week, 0.04 mg/kg/day at the second week, and 0.06 mg/kg/day at the third week and thereafter. The outcome measures were scores obtained by CARS, Aberrant Behavior Checklist (ABC), and Clinical Global Impression-Improvement (CGI-I) scale.

Results: Fifteen patients completed this study. After 8 weeks, CARS total score decreased significantly, (P=0.001). At the end of the study, social interactions and verbal communication skills of the patients were significantly improved (P<0.001, P=0.03, respectively). However, stereotypic behaviors did not show any significant change in this study. Increase in appetite and somnolence were the most reported side effects.

Conclusion: This study suggests that risperidone may be an effective treatment for the management of core symptoms of autistic disorder.