influence of omega fatty acids on mental disorders

a growing number of observational and epidemiological studies have suggested that mental illness, in particular mood disorders, is associated with decreased dietary intake and/or cellular abundance of omega-3 polyunsaturated fatty acids (pufa). this has prompted researchers to test the efficacy of omega-3 pufa in a range of different psychiatric disorders. we have critically reviewed the double-blinded placebo controlled clinical trials published prior to april 2009 to determine whether omega-3 pufa are likely to be efficacious in these disorders. most trials involved a small number of participants but were largely well designed. omega-3 pufas were well tolerated by both children and adults with mild gastrointestinal effects being the only consistently reported adverse event. there was little evidence of a robust clinically relevant effect for schizophrenia. in the case of attention deficit hyperactivity disorder (adhd) and related disorders, most trials showed at most small benefits over placebo. a limited meta-analysis of these trials suggested that benefits of omega-3 pufa supplementation may be greater in a classroom setting than at home. a meta-analysis of trials involving patients with major depressive disorder and bipolar disorder provided evidence that omega-3 pufa supplementation reduces symptoms of depression. furthermore, meta-regression analysis suggested that supplementation with eicosapentaenoic acid may be more beneficial in mood disorders than with docosahexaenoic acid (dha); although several confounding factors prevented a definitive conclusion being made regarding which species of omega-3 pufa is most beneficial. the mechanisms underlying the apparent efficacy of omega-3 pufa in mood disorders compared to schizophrenia were discussed as is a rational for the possibly greater efficacy of eicosapentaenoic acid compared to docosahexaenoic acid. while it is not currently possible to recommend omega-3 pufa as either a mono or adjunctive-therapy in any mental illnesses, the available evidence is strong enough to justify continued study, especially with regard to attention, anxiety and mood disorders.