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Fluoxetine may not treat OCD symptoms in patients with ASD

Children and adolescents with autism spectrum disorders who exhibit obsessive-compulsive disorder behaviors had significantly lower scores for OCD behaviors at 16 weeks when taking fluoxetine compared with placebo, according to findings published in JAMA. However, in prespecified analyses that accounted for several variables, the difference between the groups was nonsignificant.

“Although the evidence is not strong enough to recommend fluoxetine as a treatment, we cannot exclude that it is helpful for some individual children,” Dinah S. Reddihough, MD, of the Royal Children’s Hospital in Australia, told Healio Psychiatry. “As we gain further understanding of the effects of medication in individual children, or ‘personalized medicine,’ it may be possible to determine more precisely which children, if any, are likely to gain benefit from the use of these drugs.”

Reddihough and colleagues conducted a randomized clinical trial to determine whether fluoxetine is efficacious for reducing the severity and frequency of OCD behaviors in participants aged 7.5 to 18 years who were diagnosed with an ASD. The researchers included participants who had a total score of six or higher on the Children’s Yale-Brown Obsessive Compulsive Scale (CYBOCS-PDD).

Between Nov. 2010 and April 2017, 75 participants received fluoxetine and 71 received placebo for 16 weeks.

Among all participants (85% male; mean age, 11.2 years), 109 completed the trial. According to the researchers, the mean CYBOCS-PDD score from baseline to 16 weeks decreased from 12.8 to 9.02 (3.72-point mean decrease; 95% CI, –4.85 to –2.6) among the fluoxetine group and from 13.13 to 10.89 (2.53-point decrease; 95% CI, –3.86 to –1.19) among the placebo group. The 16-week difference between groups was –2.01 (95% CI, –3.77 to –0.25). In a prespecified model that included further adjustment for sex, verbal ability and imbalances in baseline variables, the mean difference was –1.17 (95% CI, –3.01 to 0.67), which was considered statistically nonsignificant.

“Clinicians and families should be cautious about the use of these medications where to date there has been no published evidence of their effectiveness in this population,” Reddihough said.

In a related editorial, Bryan H. King, MD, MBA, of the department of psychiatry at the University of California San Francisco’s Weill Institute for Neurosciences, emphasized the nullification of the overall findings by the prespecified analyses.

“Despite the limitations, the outcome of the trial by Reddihough and colleagues is consistent with similar trials and contributes new evidence that SSRIs do not add any value over placebo for repetitive behaviors in children and adolescents with ASD as captured in the CYBOCS-PDD,” King wrote. “Additional rigorous studies are needed, both to identify other potential treatments for core symptoms and, for SSRIs, to determine whether clinical indications other than repetitive behaviors might account for their persistent widespread use in ASD.” – by Joe Gramigna

Disclosures: King reports receiving personal fees from Genentech and from the New England Journal of Medicine outside the submitted work. Reddihough reports receiving grants from the National Health and Medical Research Council and the Royal Children’s Hospital Foundation. Please see the study for all other authors’ relevant financial disclosures.