Omega-3 fatty acids for depression in adults.

Abstract

Background: Major depressive disorder (MDD) is highly debilitating, dif ficult to treat, has a high rate of recurrence, and negatively impacts the individual and society as a whole. One emerging potential treatment for MDD is n-3 polyunsaturated fatty acids (n-3PUFAs), also known as omega-3 oils, naturally found in fatty fish, some other seafood, and some nuts and seeds. Various lines of evidence suggest a role for n-3PUFAs in MDD, but the evidence is far from conclusive. Reviews and meta-analyses clearly demonstrate heterogeneity between studies. Investigations of heterogeneity suggest differential effectsof n-3PUFAs, depending on severity of depressive symptoms, where no effects of n-3PUFAs are found in studies of individuals with mild depressive symptomology, but possible benefit may be suggested in studies of individuals with more severe depressive symptomology. Objectives: To assess the effects of n-3 polyunsaturated fatty acids (also known as omega-3 fatty acids) versus a comparator (e.g. placebo, anti-depressant treatment, standard care, no treatment, wait-list control) for major depressive disorder (MDD) in adults. Search methods: We searched the Cochrane Depression, Anxiety and Neurosis Review Group’s Specialised Registers (CCDANCTR) and International Trial Registries over all years to May 2015. We searched the database CINAHL over all years of records to September 2013. Selection criteria: We included studies in the review if they: were a randomised controlled trial; provided n-3PUFAs as an intervention; used a comparator;measured depressive symptomology as an outcome; and were conducted in adults with MDD. Primary outcomes were depressive symptomology (continuous data collected using a validated rating scale) and adverse events. Secondary outcomes were depressive symptomology (dichotomous data on remission and response), quality of life, and failure to complete studies. Data collection and analysis: We used standard methodological procedures as expected by Cochrane.