A new meta-analysis supports the link between intake of EPA and DHA omega-3 fatty acids, and reduction in major depressive disorder (MDD).
The meta-analysis only included studies in adult patients with MDD assessed using standardized clinical interviews, and excluded studies that specifically studied perinatal/perimenopausal or comorbid MDD, in order to get a more homogenous population. Studies not applying a randomized placebo-controlled trial design were also excluded. This criteria resulted in 13 studies with a total of 1233 participants (out of an original pool of 1955 studies).
The analysis of these studies showed a benefit for these omega-3 acids that was comparable to effects reported in meta-analyses of antidepressants. The effect was greater in studies supplementing higher doses of EPA and performed in patients already on antidepressants.
http://www.eurekalert.org/pub_releases/2016-03/g-nss031716.php
Mocking, R. J. T., Harmsen, I., Assies, J., Koeter, M. W. J., Ruhe, H. G., & Schene, A. H. (2016). Meta-analysis and meta-regression of omega-3 polyunsaturated fatty acid supplementation for major depressive disorder. Transl Psychiatry, 6, e756. Retrieved from http://dx.doi.org/10.1038/tp.2016.29