Newswise — A multi-site study sponsored by the National Institute of Mental Health (NIMH) finds children with autism characterized by tantrums, aggression, and/or self-injury respond favorably to the antipsychotic medication risperidone for up to six months.

Published in the July edition of the American Journal of Psychiatry, the study found the medication not only decreased aggression but also reduced repetitive behaviors and increased social interaction " all with limited side effects. The two-part study also found discontinuation after six months prompted rapid return of disruptive and aggressive behavior in most cases.

Atypical antipsychotic medications such as risperidone are of interest to doctors who treat children with autism because studies show the newer medications benefit adults with schizophrenia with fewer neurological side effects than older options.

"A variety of treatments, including medication, are used to manage aggressive behaviors in autistic children, but controlled medication trials are limited," said Dr. James McCracken, lead author and site investigator at the Semel Institute for Neuroscience and Human Behavior at UCLA. "Our findings support adding risperidone to the small arsenal of intermediate-term medication options for the tens of thousands of children with autism who display aggressive and destructive behaviors.

"The response to risperidone ranks among the most positive ever observed in children with autism for a drug treatment," said McCracken, a professor of psychiatry and biobehavioral sciences and director of the Division of Child and Adolescent Psychiatry at the David Geffen School of Medicine at UCLA.

Autism is a chronic condition that appears in early childhood. Core symptoms include impaired social interaction, delayed language development and restricted patterns of behavior. The disorder affects as many as 20 in 10,000 children. Although the causes of autism are unknown, scientific evidence point to abnormalities in brain development and a strong genetic component.

In addition to core symptoms, children with autism frequently exhibit serious behavior disturbances in response to routine environmental demands. For these disturbances, behavior therapy and medications are the two main forms of treatment.

In the multi-site study, researchers randomly assigned 101 subjects " 82 boys and 19 girls " ages 5 to 17 to receive either placebo or risperidone. Subjects who improved substantially after eight weeks continued treatment for up to six months. Researchers observed a small sample of subjects at the end of the study during the withdrawal of the medication.

Previously, the largest extended studies of medication for autism with haloperidol, an older antipsychotic, showed the drug to be modestly effective but accompanied by neurological and other side effects.

Past research into the effect of risperidone on children with autism found the medication effective for short-term treatment of aggressive behaviors related to autism in children. Side effects to risperidone are usually well-tolerated, with some complaints of weight gain. The intermediate-term risperidone study was conducted at five sites of the Research Units of Pediatric Psychopharmacology (RUPP) network, which is funded by NIMH. The RUPP network is composed of research units devoted to conducting studies to test the efficacy and safety of medications commonly used off-label to treat children and adolescents. In clinical practice, many medications are used in the treatment of autism, but few medications have been carefully studied to determine the safety and effectiveness of the medication for the treatment of childhood illnesses.

Principal investigators at other research sites included Michael G. Aman of Ohio State University, Dr. Christopher J. McDougle of Indiana University, Lawrence Scahill of Yale University, Elaine Tierney of Kennedy Krieger Institute at Johns Hopkins University, and Dr. Benedetto Vitiello of the NIMH. Faculty at Columbia University, Yale University and Nathan Kline Institute participated in data collection, coordination and analysis.

Funding for the study was provided by the National Institute of Mental Health, National Institutes of Health Division of Research Resource General Clinical Research Center, and the Korczak Foundation. Study medications were donated by Janssen Pharmaceutica.

The Semel Institute for Neuroscience and Human Behavior at UCLA is an interdisciplinary research and education institute devoted to the understanding of complex human behavior, including the genetic, biological, behavioral and sociocultural underpinnings of normal behavior, and the causes and consequences of neuropsychiatric disorders. More information about the Institute is available online at

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American Journal of Psychiatry (Jul-2005)