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Risperidone Effective in Treating Behavioral Problems in Autism

Risperidone improved behavior in children with autism and demonstrated a strong safety profile, including few drug-interactions and side effects, according to a large study sponsored by the US National Institute of Mental Health. Risperidone belongs to a class of drugs called “atypical” anti-psychotics.

The study’s primary goal was to evaluate the efficacy and safety of risperidone (the first widely available atypical anti-psychotic drug) in children with autism who had serious behavioral disturbances.

"Although this study did not attempt to treat the core symptoms of autism, our findings suggest that risperidone can be useful in treating moderate to severe behavior problems that are associated with autism in children," said Lawrence Scahill, PhD, principal investigator at the Yale Child Study Center site.

Aims and Results of the Study

The study was conducted at several medical locations over eight weeks and included a total of 101 children and adolescents (82 boys and 19 girls), aged 5-17 years. Participants randomly received either placebo or risperidone, one of a new class of anti-psychotic medications called “atypical”.

The main objective of treatment was “to reduce impairing behavioral symptoms such as aggression, explosive outbursts, or self-injurious behavior, without significant side effects,” according to a study summary presented at

Results showed risperidone to be significantly more effective than placebo in improving behavior. According to the study’s stringent definition of “improvement”, 69% of the children who received risperidone were “much” or “very much” improved by the end of the study – compared with only 12% of children receiving placebo.

According to, these results constitute “the largest positive effect by a medication ever observed in children with autism.”

Side Effects: Risperidone was well tolerated by the children and showed few neurological side effects. However, risperidone was associated with a notable body-weight increase (an average of 6 lbs over the 8-week period).

Autism – Symptoms and Behavior

Autism is a chronic condition appearing in early childhood and characterized by core symptoms that include a reduced ability to relate socially, delayed language development, and restricted patterns of behavior. Autism affects up to 20 per 10,000 children. The causes of autism are unknown in most cases, but evidence suggests abnormalities in brain development. Moreover, twin and family studies indicate a strong genetic component.

Children with autism also frequently demonstrate significant behavioral disturbances, such as self-injury, aggression, hyperactivity and tantrums in response to routine environmental demands. Treatment for these disturbances primarily consists of behavioral therapy and medications.

Doctors have tried to treat autism with a variety of medications, with limited success – only haloperidol has shown superior effect over placebo in helping to reduce serious behavioral problems in more than one placebo-controlled study. Moreover, concerns about haloperidol’s neurological and other side effects hamper widespread use in children.

“Atypical” Anti-psychotics

Although few studies of atypical anti-psychotic medications have been conducted in children, this drug class shows promise in treating children with autism. Clinical studies have shown that atypical anti-psychotics offer great benefit in adults with schizophrenia, as well as causing fewer neurological side effects than older medications.

Posted: July 2005