A drug that some have tried to treat autism in children does no better than a placebo, according to a new study.

Citalopram is meant to treat the repetitive behaviors that children with autism spectrum disorders often show, a news release from the National Institute of Mental Health about the study said. The drug also had a higher risk of side effects.

Citalopram is an antidepressant that has been used to treat other forms of obsessive compulsive disorders, so some had hoped it would also help with autism.

The results were based on a randomized trial of 149 young patients with autism. In the group that got the drug, about 33 percent had fewer symptoms after 12 weeks. Among those that got a placebo, 34 percent showed fewer symptoms.

One researcher said that both groups saw adverse side effects as well, though that could be from normal changes in autism or common diseases. But those who took citalopram were also more likely to have more anger and impulsiveness, lower concentration, and more diarrhea and insomnia.

According to the researchers, the study results may challenge the underlying premise that repetitive behaviors in autistic children with ASD are similar to OCD.

The study was published in the June 2009 issue of Archives of General Psychiatry.