Food and Behaviour Research

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Efficacy of omega-3 highly unsaturated fatty acids in the treatment of depression

Hallahan B, Ryan T, Hibbeln JR, Murray IT, Glynn S, Ramsden CE, SanGiovanni JP, Davis JM. (2016) Br J Psychiatry. 209(3): 192-201 Epub 2016, Apr 21. doi: 10.1192/bjp.bp.114.160242. 

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Trials evaluating efficacy of omega-3 highly unsaturated fatty acids (HUFAs) in major depressive disorder report discrepant findings.


To establish the reasons underlying inconsistent findings among randomised controlled trials (RCTs) of omega-3 HUFAs for depression and to assess implications for further trials.


A systematic bibliographic search of double-blind RCTs was conducted between January 1980 and July 2014 and an exploratory hypothesis-testing meta-analysis performed in 35 RCTs including 6665 participants receiving omega-3 HUFAs and 4373 participants receiving placebo.


Among participants with diagnosed depression, eicosapentaenoic acid (EPA)-predominant formulations (>50% EPA) demonstrated clinical benefits compared with placebo (Hedge's G= 0.61, P<0.001) whereas docosahexaenoic acid (DHA)-predominant formulations (>50% DHA) did not. EPA failed to prevent depressive symptoms among populations not diagnosed for depression.


Further RCTs should be conducted on study populations with diagnosed or clinically significant depression of adequate duration using EPA-predominant omega-3 HUFA formulations.

© The Royal College of Psychiatrists 2016.


This new systematic review and meta-analysis extends and confirms the pattern of findings shown in previous studies of omega-3 for depression, i.e. that EPA-rich formulations are effective in patients with clinically diagnosed depression.

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