Risperidone Monotherapy in Children and Adolescents with Autism Spectrum Disorders : A Naturalistic Study

Objectives : We retrospectively investigated the efficacy and tolerability of risperidone monotherapy in subjects with autism spectrum disorder (ASD). In addition, we did mixed effect model analysis of the effects of risperidone in patients with ASDs naturalistically treated in a routine clinical setting to determine whether the clinical effects were maintained and the side effects were tolerable. Methods : This retrospective study assessed children and adolescents with ASD, who were on risperidone monotherapy from July 2010 to July 2011 at the Child and Adolescent ASD Clinic at Seoul National Hospital. Outcome measures included the Clinical Global Impression-Severity of Illness (CGI-S) and the CGI-Improvement (CGI-I) scales along with other clinical indices: dosage, target symptoms, and side effects. Results : The mean dose of risperidone in 47 children and adolescents with ASD (40 males, 7 females; age range 5-19 years) who were on risperidone monotherapy was , and the mean duration of the treatment period was . Aggressive behavior, stereotypic behavior, irritability, and self-injurious behavior were the most frequent target symptoms of risperidone. The most common side effects were weight gain followed by somnolence and extrapyramidal symptoms. In a mixed effects model analysis of CGI-I scores, the mean CGI-I score at the 1 month follow-up was significantly different from the mean CGI-I score of the 3-month follow-up (p