Treatment of Autism in Children and Adolescents

This study is designed to determine the effectiveness of risperidone, a drug treatment for the interfering symptoms of Autistic Disorder in children and adolescents between the ages of 5 and 17. Between 100 and 120 patients will be participating in this research study at five academic medical centers in the United States. The primary aim of the treatment is to reduce impairing behavioral symptoms such as aggression, explosive outbursts, or self-injurious behavior, without significant side effects. A secondary aim is to evaluate possible improvement in the level of social relatedness, attention, motor coordination, and short-term memory. This study is a placebo-controlled, double-blind study (neither the investigators nor patients know if the treatment being given is risperidone or an inactive substance, placebo). Patients will be asked to participate for 6 to 8 months. For the first 8 weeks, patients will receive either risperidone or placebo, randomly chosen. At the end of the 8 weeks, those patients who have improved and were on risperidone will be asked to continue on this medication for another 4 months. The last two months of the study are again double-blind (neither patients nor investigators know treatment). Patients will either continue risperidone treatment or be gradually tapered from risperidone (placebo-substitution). This blinded discontinuation phase will last 2 months during which patients will be closely monitored for recurrence or worsening of symptoms. Patients who have been treated with placebo in the first 8 weeks of the study and have not improved will be treated with risperidone. Weekly visits are required for the first 8 weeks of the study, monthly visits for the following 4 months, and weekly visits during the last 2 months of the study.