Omega-3 supplementation significantly improves depression in people with major depressive disorder (MDD) and those with depression symptoms alike according to a recent meta-analysis which combined results from many similar randomised, controlled clinical trials. It included 11 trials on patients with diagnosed MDD according to the DSM definition and 8 trials on people with depressive symptoms but no formal diagnosis of MDD that had been published up to August 2013.

EPA appeared to be more effective for reducing depressive symptoms than DHA. In addition, omega-3’s seemed to be most valuable as treatments to be used along with conventional medication rather than by themselves. The measured effectiveness of the omega-3 treatments tested in all the studies were not influenced by the number of patients in the study, baseline depression severity, trial duration, age of the patients or study quality.

1. Grosso G et al. Role of omega-3 fatty acids in the treatment of depressive disorders: a comprehensive meta-analysis of randomized clinical trials. PLoS One 2014 May 7;9(5):e96905.