Principal investigator Maria Carrasco of the University of Michigan in Ann Arbor, said researchers examined 15 randomized, double-blind, placebo-controlled trials of serotonin re-uptake inhibitors in which the duration of treatment was at least four weeks.
Five published studies and one unpublished trial were used in the analysis.
The study, published in the journal Pediatrics, found among the six trials, which included 365 patients, a small benefit from the antidepressants occurred for repetitive behaviors such as obsessions and compulsions in autism. Three trials reported some benefit and three reported some or no benefit.
"The pharmacological treatment of repetitive behaviors in autism is often difficult and in great need of further research," Carrasco told Medscape Medical News. "Pharmacological treatments are simply not available to address this important core aspect in autism, but are urgently needed."
The researchers found significant evidence of publication bias using both the Egger regression test and by performing a regression of the adjusted sample size versus the trial effect. Using only data from positive published results, and not the unpublished studies, creates a publication bias creating a more positive effect from the medication, the researchers said.