Melbourne, Australia—Treatment with the antidepressant fluoxetine shows promise for treating children and adolescents with autism-spectrum disorders (ASDs).

A report in JAMA notes that the selective serotonin receptor inhibitor (SSRI) significantly lowered scores for obsessive-compulsive behaviors at 16 weeks but cautions that interpretation is limited by null findings and imprecise estimates from prespecified analyses that accounted for confounding factors and baseline imbalances.

Background information in the article points out that ASDs “are characterized by impairments in communication and social relatedness and restricted and repetitive interests and behaviors.” It also adds that more than half of children and adolescents with ASDs are prescribed medication, with 21% to 32% receiving SSRIs to reduce the severity of core behaviors of AUDs even though their efficacy remains uncertain.

Royal Children’s Hospital–led researchers sought to determine the efficacy of fluoxetine for reducing the frequency and severity of obsessive-compulsive behaviors in ASDs. To do that, the Australian study team performed a multicenter, randomized, placebo-controlled clinical trial.

Included were participants aged 7.5 to 18 years with ASDs and a total score of 6 or higher on the Children’s Yale-Brown Obsessive Compulsive Scale, modified for pervasive developmental disorder (CYBOCS-PDD). The pediatric patients were recruited from three tertiary health centers across Australia, with enrollment beginning in November 2010 and ending in April 2017, with follow-up ending August 2017.

With 75 participants randomized to receive fluoxetine, another 71 were given placebo. The study team said the medication was initiated at 4 or 8 mg/d for the first week, depending on weight, and then titrated to a maximum dose of 20 or 30 mg/d over 4 weeks. Treatment duration was 16 weeks.

Defined as the primary outcome was the total score on the CYBOCS-PDD (scores range from 0-20; higher scores indicate higher levels of maladaptive behaviors; minimal clinically important difference, 2 points) at 16 weeks postrandomization.

Results indicate that the mean CYBOCS-PDD score from baseline to 16 weeks decreased in the fluoxetine group from 12.80 to 9.02 points (3.72-point decrease; 95% CI, -4.85 to -2.60) and in the placebo group from 13.13 to 10.89 points (2.53-point decrease; 95% CI, -3.86 to -1.19). Researchers emphasize that the between-group mean difference at 16 weeks was -2.01 (95% CI, -3.77 to -0.25; P = .03) (adjusted for stratification factors), and in the prespecified model with further adjustment, it was -1.17 (95% CI, -3.01 to 0.67; P = .21).

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