A Study to Evaluate the Efficacy and Safety of Risperidone (R064766) in Children and Adolescents With Irritability Associated With Autistic Disorder

Subjects weighing less than 20 kilogram (kg) received risperidone 0.25 milligram per day (mg/day) up to Day 4. On Day 4, dose was titrated in increments of 0.25 mg/day (up to a daily dose of 1.0 mg) at the regular study visit thereafter till Week 8. Subjects weighing greater than or equal to (\>=) 20 kg received risperidone 0.5 mg/day up to Day 4. On Day 4, dose was titrated in increments of 0.5 mg per day (up to a daily dose of 2.5 mg) at the regular visit thereafter till Week 8. The maximum daily dose for subjects weighing \>= 45 kg was 3.0 mg. For subjects weighing \>=45 kg, the maximum daily dose was 3.0 mg.

Subjects will receive placebo matching with risperidone orally up to 8 weeks.