ω-3 Fatty acids for major depressive disorder in adults: an abridged Cochrane review

Cochrane systematic review and meta-analysis of 26 independent studies involving 1458 adults with major depressive disorder. Studies were conducted in varied countries and settings, with active-arm groups including both monotherapy and adjunctive treatment comparisons against placebo, antidepressants, or standard care.

Oral omega-3 fatty acid regimens, mainly eicosapentaenoic acid (EPA) alone or EPA/docosahexaenoic acid (DHA) combinations, were tested across trials at doses ranging from EPA 1 g/day to EPA 3 g/day and EPA/DHA combinations such as 0.93/0.75 g/day and 1.05/0.15 g/day. These active interventions were compared with placebo, antidepressants, or standard care in adults with major depressive disorder.

Overall, the evidence is insufficient and of very low quality to determine whether omega-3 fatty acids are effective for major depressive disorder. Pooled analyses suggested a small-to-modest benefit on depressive symptoms versus placebo, but the estimate was imprecise and may not be clinically important. Adverse events appeared similar between groups, although safety evidence was uncertain. In the single available comparison with antidepressants, there was no clear difference.

The evidence base was very low quality, with imprecise estimates and concern for bias. Trial populations and omega-3 regimens were heterogeneous, limiting confidence in pooled effects and generalizability. Only one antidepressant comparison was available, and more adequately powered, well-designed trials are needed.