Prozac proves no better than a placebo in treating kids with autism

Prozac, a commonly prescribed medication for kids and teens with autism, is no more effective than a placebo at treating obsessive-compulsive behaviors, a small study finds.

The results of the randomized clinical trial, published October 22 in JAMA, cast further doubt on the widespread practice of prescribing a class of antidepressants known as selective serotonin reuptake inhibitors, or SSRIs, to treat children with autism who have these behaviors, says pediatric neurologist Ann Neumeyer. 

“We really don’t have any good medications that have yet been studied in children with autism for these behaviors,” says Neumeyer, the medical director of the Massachusetts General Hospital Lurie Center for Autism in Lexington, who wasn’t involved in the study. “That’s a problem.”

Autism spectrum disorders encompass a diversity of symptoms, but common among them are obsessive-compulsive behaviors (SN: 10/16/18). Individuals with autism can become hyperfocused on specific ideas or objects and can engage in ritualistic “tics,” such as rocking or hand-waving. For many individuals, these symptoms interfere with everyday functioning.

SSRI antidepressants account for a quarter to a third of all prescriptions to children and teens with autism, according to pediatrician Dinah Reddihough at the Murdoch Children’s Research Institute in Melbourne, Australia. “Despite their widespread use, there is no evidence of effectiveness of SSRIs for autism spectrum disorders in children,” she says.

A 2013 review backs Reddihough up. It analyzed nine clinical trials involving 320 participants and found that SSRIs provided no therapeutic benefit for children and adolescents with autism, though the authors called for larger studies to investigate the question better.

Reddihough and her colleagues spent seven years recruiting participants for their clinical trial of Prozac, also known as fluoxetine, to test whether the drug was effective for children with autism. A total of 109 kids and teens, aged 7½ to 18, completed the four-month trial in which they were randomly assigned to receive either a low dose of up to 20 or 30 milligrams per day of fluoxetine or a placebo. The researchers tracked changes in the subjects’ obsessive and compulsive symptoms, as measured by a behavioral survey used in other studies, before and after treatment. 

At first, the fluoxetine group appeared to show a slight but significant easing of obsessive-compulsive symptoms after four months compared with the placebo. But after the researchers controlled for factors including age, sex and the severity of symptoms at the start of the trial, the difference vanished. Fluoxetine did no better than the placebo.

The relatively small sample size could have limited the researchers’ ability to detect a benefit from the drug, Neumeyer says. “It’s possible that, with higher numbers, they would’ve found subgroups who benefit from SSRIs,” she says. “That’s the painful part of this [kind of] research though; you’re left wondering.”

Still, “it’s really important that negative results are published,” Neumeyer says. The new study helps show that “SSRIs are not the medication clinicians should go to first” for children and adolescents with autism.