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Fish-Oil Supplements for Depression?

Compared with the placebo group, the group with the lowest E-EPA dosage showed significant 12-week declines in depression scores.

Epidemiologic data indicate that major depression is less common in populations that consume 0.5-1.0 g/day of omega-3 polyunsaturated fatty acids (found in seafood) than in populations that consume less. Researchers have begun to test the effectiveness of omega-3 fatty-acid supplementation for treating patients with schizophrenia (see Journal Watch Psychiatry Oct 24 2002) and mood disorders. Now, these researchers have assessed the antidepressant effect of supplementation with ethyl-eicosapentaenoic acid (E-EPA, a precursor of docosahexaenoic acid, the most important omega-3 fatty acid). In a double-blind fashion, researchers randomized 70 patients (recruited by family physicians) with moderate levels of depression despite antidepressant treatment of unstated duration to receive 12 weeks of adjunctive therapy with 1 of 3 E-EPA dosages (1, 2, or 4 g/day) or placebo.

Compared with the placebo group, the 1-g E-EPA group -- but not the 2-g and 4-g groups -- showed significant 12-week declines in scores on 3 depression scales. In intent-to-treat (efficacy) and completer (effectiveness) analyses, the 1-g group had the highest percentage of patients with 50% improvement in depression scores (range, 47%-69% for the 3 scales). E-EPA was well tolerated.

Comment: Phospholipids, which contain fatty acids, constitute almost 60% of the brain's solid mass and have an important role in cellular signaling. Although the exact mechanism by which phospholipids might augment the effects of antidepressants is unclear, the authors cite research suggesting that higher doses of omega-3 supplements (or their precursors) can alter the balance between omega-3 and omega-6 levels; this balance may affect depression more than levels of either fatty acid alone. It is possible that the 1-g E-EPA dose was more effective than the others because it optimized this balance. We do not know whether omega-3 fatty acids would benefit the more severely ill patients seen in psychiatric practice.

— Steven Dubovsky, MD

Published in Journal Watch Psychiatry December 4, 2002

Citation(s):

Peet M and Horrobin DF. A dose-ranging study of the effects of ethyl-eicosapentaenoate in patients with ongoing depression despite apparently adequate treatment with standard drugs. Arch Gen Psychiatry 2002 Oct; 59:913-9.

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