September 8, 2011 — Supplementation with omega-3 fatty acid may decrease symptoms of attention-deficit/hyperactivity disorder (ADHD) in children, a new meta-analysis suggests.
In an evaluation of 10 trials with 699 total children with ADHD, investigators found that those who received omega-3 supplements had a "small but significant" improvement in symptom severity compared with those who were given placebo. This effect was also significant in the children who received supplements that specifically contained higher doses of eicosapentaenoic acid.
"I was actually expecting this treatment to not be effective at all, that we shouldn't expect much from a nutritional supplement that often takes a while to work. So the results were a surprise to me," lead author Michael H. Bloch, MD, assistant professor at the Yale Child Study Center at Yale University School of Medicine in New Haven, Connecticut, told Medscape Medical News.
"However, I would hope that nobody thinks the take-home message is that omega-3s are the answer for everyone in lieu of traditional medications," said Dr. Bloch.
In fact, the investigators note that the relative efficacy of this treatment "was modest compared with currently available pharmacotherapies for ADHD, such as psychostimulants, atomoxetine, or a2 agonists."
Still, because of its "relatively benign side-effect profile," they write, omega-3 supplements may be a reasonable add-on to traditional interventions or an option for families who do not want other psychopharmacologic treatments.
"I think the medication treatments we currently have for ADHD work best. But omega-3 represents a potentially safer alternative, especially in mild cases," said Dr. Bloch.
The study was published online August 16 in the Journal of the Academy of Child and Adolescent Psychiatry.
Past Research Results "Mixed"
According to the investigators, past research has shown that individuals with ADHD have omega-3 differences in both plasma and erythrocyte membranes compared with their healthy peers.
"Omega-3 fatty acids have anti-inflammatory properties and can alter central nervous system cell membrane fluidity and phospholipid composition," they explain.
Although several studies have looked at how effective omega-3 is in treating ADHD, the results have been mixed, prompting the need for the current meta-analysis.
The researchers examined 10 randomized control trials that compared omega-3 supplements with placebo in children with ADHD. All studies were conducted between 2001 and 2009 and lasted between 7 weeks and 4 months.
ADHD severity improvement, as measured by mean differences in rating scales, was the primary outcome. In secondary analysis, the investigators assessed dosing effects of the following omega-3 fatty acids found within the supplements used: eicosapentaenoic acid, docosahexaenoic acid, and α-linolenic acid.
Efficacy When Studies Combined
Results showed significant efficacy of omega-3 supplementation compared with placebo in only 2 of the trials. Of the remaining studies, 6 showed no benefit at all, and 2 showed benefit only on some of the ADHD rating scales.
Still, the overall analysis did show a significant improvement in ADHD symptoms for the participants receiving omega-3 compared with those receiving placebo (standard mean difference [SMD], 0.31; P < .0001).
"Looking at these studies individually, most did not find that omega-3 was effective. It was only when you combined them that the effect became significant to a small degree," said Dr. Bloch.
Results were similar when parental ratings of ADHD severity were assessed (SMD, 0.29; P = .0002), and when separate evaluations of inattentive (SMD, 0.29; P = .009) and hyperactivity (SMD, 0.23; P = .005) symptoms were conducted.
Omega-3 supplements that included higher doses of eicosapentaenoic acid were also significantly associated with lowering ADHD symptoms (P = .04).
There were no significant differences found for any dose of docosahexaenoic acid or α-linolenic acid, or between omega-3 monotherapy vs augmenting traditional ADHD medications with omega-3.
"No evidence of publication bias or heterogeneity between trials was found," write the researchers.
However, "because of poor quality and potential issues of blinding in many of the included trials," further studies are needed to replicate the results, they write.
"I think this is something that's potentially useful for families who either don't respond to treatment with traditional medications or are hesitant to take them because of side effects," said Dr. Bloch.
He added that he hopes a future multisite trial with at least 400 children will be conducted to finally give "a definitive answer on how much omega-3 might really work."
Missing Side Effects Profile
"This is a well-done meta-analysis with attention to several aspects," Jaswinder Kaur Ghuman, MD, associate professor of psychiatry and pediatrics at the University of Arizona, Tucson, told Medscape Medical News.
However, she added that one of her concerns is the investigators' statement that omega-3 treatments have a benign side effects profile.
"They did not include analysis of side effects from the included studies, neither do they discuss what are the side effects of omega-3 supplements. Anecdotally, I have seen some people be unable to tolerate [these] supplements due to gastrointestinal upset."
Dr. Ghuman said that if parents are interested in letting their children try omega-3 supplements for their ADHD symptoms, "they should be advised to use adequate doses for effectiveness and tolerability should be carefully monitored."
The study was supported by grants from the National Institutes of Health and from the National Center for Research Resources, and by the National Institute of Mental Health, the American Psychiatric Institute for Research and Education/Eli Lilly and Co Psychiatric Research Fellowship, the American Academy of Child and Adolescent Psychiatry/Eli Lilly and Co Pilot Research Award, the Trichotillomania Learning Center, and the National Alliance for Research on Schizophrenia and Depression. The study authors have disclosed no relevant financial relationships.
J Am Acad Child Adolesc Psychiatry. Published online August 16, 2011. Abstract