MONDAY, April 23 (HealthDay News) -- Studies that show a type of
antidepressant eases autism symptoms are more likely to get
published in medical journals than studies concluding the drugs
don't improve common behaviors such as rocking and hand-flapping,
new research says.
That "publication bias" may mean that physicians believe the
medications -- known as selective serotonin reuptake inhibitors
(SSRIs) -- are more effective than they really are for children
with these behaviors. Indeed, when researchers combined the data
from published studies and those that never made it into print, the
new analysis showed that SSRIs don't help repetitive behaviors much
at all.
"At least from what we have right now, we need more information to determine if SSRIs are useful in treating repetitive behavior," said study author Melisa Carrasco, of the neuroscience graduate program at the University of Michigan in Ann Arbor. "I don't think we're trying to say they should not be used at all in autism. There is some compelling evidence toward their use in treating anxiety disorders in autism."
The study, in the May print issue of
Pediatrics, appears online April 23.
The study also calls into question the effectiveness of current
methods used to evaluate drugs, particularly pediatric drugs, in
the United States. One expert said the findings have implications
for countless other drug trials for other conditions.
It's long been recognized that drug trials that show the drug is
effective are more likely to be published in peer-reviewed
journals, where the results are widely read and disseminated to
doctors, said Dr. Scott Denne, a professor of pediatrics at Indiana
University School of Medicine, who wrote an accompanying
editorial.
"Positive studies are exciting and potentially groundbreaking. Negative studies are not particularly exciting and at least in the estimation of both physicians and investigators, they don't really change anything, even though that isn't necessarily true," Denne said.
Current U.S. law requires that investigators submit a summary of
the results of drug trials on ClinicalTrials.gov, a national
registry of clinical studies. But often, researchers don't submit
their results, and the information is never published on the
government website, he said.
"A substantial number of trials are not having the results posted anywhere," Denne said. This deprives pediatric researchers and the public of valuable information, and may mean that trials are unnecessarily repeated.
Carrasco and her colleagues searched PubMed (a U.S. National
Institutes of Health database) and ClinicalTrials.gov for
randomized, double-blind, placebo-controlled trials (considered the
gold standard of research) on using SSRIs to treat repetitive
behavior in people with autism. Researchers identified five
published trials and five unpublished trials marked as completed on
ClinicalTrials.gov.
A meta-analysis (pooled analysis) of the published studies found
a small but significant improvement in repetitive behaviors,
including obsessions and compulsions, among autistic kids treated
with SSRIs. When the unpublished studies were included, that
benefit vanished.
About one in 88 U.S. children has autism, a neurodevelopment
disorder characterized by problems with social interaction,
communication and restricted interests and behaviors. That includes
repetitive behaviors, such as arm-flapping or head-banging; having
an obsessive interest in one topic; having a need to stick to a
specific ritual or routine; and experiencing distress or agitation
when that routine gets disrupted.
More information
To learn more about autism treatments, visit
Autism Speaks.