Caring for children with autism who demonstrate self-injurious or aggressive behaviors often poses a number of serious challenges to parents and educators. Several different psychotropic medications have been studied in the management of these behaviors, but only haloperidol has demonstrated efficacy in more than one study. Concerns about acute extrapyramidal symptoms and the long-term risk of tardive dyskinesia have limited the use of haloperidol. Atypical antipsychotic agents that are now available have reduced risks of extrapyramidal side effects. McCracken and associates of the Research Units on Pediatric Psychopharmacology Autism Network report on the use of one of the newer antipsychotics, risperidone, in autistic children with aggressive behaviors.

The Network group screened 270 autistic children five to 17 years of age with aggressive behavior (tantrums, self-injurious behavior, or a combination), of which 101 were enrolled in the study. Any child already receiving a psychotropic agent that was deemed effective for behavior control was excluded, as were any children who improved simply as a result of increased clinical contact during the first two weeks of the study, before medication was administered. Aggressive behavior was quantified by clinicians and parents using two previously validated behavior scales.

During the initial eight weeks, children were randomly assigned to receive treatment with risperidone or placebo. Those randomized to risperidone were typically started on a dosage of 0.5 mg at bedtime. On day 4, this dosage was increased to 0.5 mg twice daily. The dosage was then gradually titrated up in 0.5-mg increments over a one-month period until behavior was improved, a side effect intervened, or a maximum of 2.5 mg per day was reached (1.0 mg in the morning and 1.5 mg at bedtime). A positive response was defined as a reduction of at least 25 percent on the irritability rating portion of the Aberrant Behavior Checklist or a “much improved” or “very much improved” ranking on the Clinical Global Impressions–Improvement scale.

Children randomized to risperidone had a positive response in 69 percent of cases, compared with a 12 percent response rate in the children given placebo. In 68 percent of children with an initial positive response, this improvement was maintained over six months of follow-up.

No child treated with risperidone had to be withdrawn from the study because of adverse events. The most commonly reported side effects that were significantly different from those in the placebo group were increased appetite (73 percent) and fatigue (59 percent). The investigators noted that fatigue subsided in most cases after six weeks of treatment, but no specific numbers were given. The six-month length of the study was too short to offer any information regarding the risk of tardive dyskinesia.

The authors concluded that risperidone was effective for short-term treatment of aggressive behaviors and was well tolerated in the majority of children with autism.