Ritalin was consistently more effective in improving inattention, distractibility, hyperactivity and impulsivity than placebo in a group of autistic children who participated in a recent study.

Children with autism and other pervasive developmental disorders (PDDs) often have symptoms of hyperactivity, distractibility and impulsiveness that require treatment. Some previous small studies on the use of medications to treat hyperactivity in these children have shown promise, but side effects -- including irritability and social withdrawal -- have been common.

David J. Posey, MD, of the Indiana University School of Medicine and colleagues in the Research Units on Pediatric Psychopharmacology (RUPP) Autism Network conducted a randomized, placebo-controlled crossover trial to determine whether methylphenidate would be effective in reducing hyperactivity and impulsiveness in children with PDDs.

Consistently More Effective

The trial included a one-week phase to test whether the participants could tolerate three different dose levels of the medication. This was followed by a four-week crossover phase during which the children were given one of three doses of methylphenidate or placebo in random order to assess effectiveness.

Children showing a positive response were treated for an additional eight-week period to ensure that gains were stable. Response to treatment was assessed by parents and teachers using standardized ratings of behavior.

Seventy-two children, aged five to 14 years participated in the study. Six participants had intolerable negative side effects with more than one dosage level and withdrew from the study.

Sixteen of the remaining children had intolerable negative side effects at the highest dose and were randomized to a modified crossover phase that omitted the highest dose.

Seven participants withdrew due to intolerable negative side effects during the crossover phase -- three at the highest dose, three at the medium dose and one while receiving the lowest dose. One child withdrew from the study for unspecified reasons

Forty-four (76 percent) of the 58 participants who completed the crossover phase of the study responded during at least one of the four treatment conditions, the researchers report. Methylphenidate was consistently more effective in improving inattention, distractibility, hyperactivity and impulsivity than placebo.

'A Reasonable Choice'

"At present, methylphenidate is a reasonable choice to target hyperactivity in the context of PDDs, given modest group effects and a response rate that approaches 50 percent," the authors conclude.

"However, caregivers should be cautioned about the strong possibility of adverse effects," they say.

"In addition, practitioners should be prepared to suspend treatment if considerable adverse effects are reported. Further secondary analyses are planned to better delineate individual responses and other moderators of response, including genotype," the authors note.