Mixed Evidence for Omega-3 Supplementation for Major Depressive Disorder

A meta-analysis of the Omega-3 fatty acid EPA (eicosapentaenoic acid) as therapeutic supplement for major depression followed the above study online September 6 in the Journal of Clinical Psychiatry.¹ The investigators noted prior data suggesting that EPA exerts greater efficacy than DHA.

In evaluating 15 trials involving 916 participants, the investigators associated supplements containing at least 60 % EPA with statistically significantly better depression symptom measures. There was no indication of DHA efficacy, which, the investigators suggest, "may block beneficial effects of EPA at about a 1:1 dose ratio."

Although noting that long-term efficacy or health benefits of Omega-3 supplementation is yet to be determined, this study's findings suggest to the investigators that 2000mg of EPA daily from a supplement containing at least 60% EPA could be beneficial.

Another recent investigation of Omega-3 supplementation, in the August Journal of Clinical Psychiatry, used just such an EPA/DHA mixture, and a safflower oil placebo in an 8-week randomized controlled trial in 432 adults with depression.²

These investigators reported a benefit of the supplementation over placebo for depression symptoms measured on the MADRS in patients without comorbid anxiety disorders; but only a trend toward superiority in the heterogeneous sample. Although they note that patients with depression and comorbidities can also be less responsive to antidepressant treatment, they acknowledged that EPA supplementation "may not sufficiently target neurobiologic substrates common to depression and anxiety disorders, such as the serotonin system."

References

1. Sublette ME, Ellis SP, Geant AL, Mann JJ. Meta-analysis of the effects of eicosapentaenoic acid (EPA) in clinical trials in depression. J Clin Psychiatry. Published online ahead of print (doi:10.4088/jcp.10m06634) accessed 9/23/11.

2. Lesprance F, Frasure-Smith N, St-Andr E, et al. The efficacy of Omega-3 supplementation for major depression: A randomized controlled trial. J Clin Psychiatry. 2011; 72:1054-1062.