Bottom line: Taking 1-4 grams per day of O3FA can decrease symptoms of depression, when the EPA component of the supplement is at least 60% of the total fatty acid content. DHA, another omega-3, should not be used by itself or make up more than 40% of the total fatty acid content.
Background: Many studies have been published looking at the usefulness of omega-3 fatty acids in the treatment of depression, bipolar disorder, schizophrenia and other conditions. The results have been conflicting and confusing. Recent articles in the Journal of Clinical Psychiatry (Dec. 2011) and Current Psychiatry (Sept. 2012) help to make sense of the data. Meta-analyses of fatty acid studies in the treatment of depression have found that when used alone the omega-3 fatty acids are not effective in decreasing depressive symptoms. DHA, one of the major omega-3’s, is not helpful for depression. EPA, another omega-3, is effective. However, the benefit from from EPA is most apparent when
* the depression is on the severe end of the spectrum
* the patient is on antidepressant treatment (the fatty acid is not used alone)
* EPA makes up at least 60% of the fatty acid content of the supplement
The amount of omega-3 that works best has not been determined. It is recommended that at least 1 gram be taken each day, with a maximum dose of perhaps 4 grams. Higher doses have been associated with less benefit.
Example: If you are taking an antidepressant, say sertraline 150 mg/d or venlafaxine 225 mg/d, and you are still suffering from significant symptoms of depression, and do not want to increase the dose (a reasonable option in both cases), adding 1-2 grams/d of omega-3 fatty acid (with EPA at least 60% of the total) made by a reputable company may be a good choice. There is no evidence whether it is more or less likely to help continuing symptoms of depression than any of the many other options, at least so far. Side effects are pretty minimal, unless you get the fishy tasting burps. Also, the omega-3s are not recommended for someone with a bleeding disorder. Eating fish 2-3 times a week(at least those high in omega-3s, such as salmon, sardines, herring and halibut) will get you plenty of omega-3.
1) Morreale, M Omega-3 Fatty Acids for psychiatric Illness. Current Psychiatry Vol. 11, No. 09 / September 2012
2) Sublette,M et al Meta-Analysis of the Effects of EPS in Clinical Trials of Depression. Journal of Clinical Psychiatry2012;72(12):1577