Addition of omega-3 fatty acid to maintenance medication treatment for recurrent unipolar depressive disorder.

OBJECTIVE Studies have reported that countries with high rates of fish oil consumption have low rates of depressive disorder. The authors studied a specific omega-3 fatty acid, the ethyl ester of eicosapentaenoic acid (E-EPA), as an adjunct to treatment for depressive episodes occurring in patients with recurrent unipolar depressive disorder who were receiving maintenance antidepressant therapy. METHOD Twenty patients with a current diagnosis of major depressive disorder participated in a 4-week, parallel-group, double-blind addition of either placebo or E-EPA to ongoing antidepressant therapy. Seventeen of the patients were women, and three were men. RESULTS Highly significant benefits of the addition of the omega-3 fatty acid compared with placebo were found by week 3 of treatment. CONCLUSIONS It is not possible to distinguish whether E-EPA augments antidepressant action in the manner of lithium or has independent antidepressant properties of its own.