Research has found low blood levels of eicosapentaenoic acid in depressed patients. The researchers tested the antidepressive effect of ethyl-eicosapentaenoate in 70 patients with persistent depression despite ongoing treatment with an adequate dose of a standard antidepressant. Patients were randomized on a double-blind basis to placebo or ethyl-eicosapentaenoate at dosages of 1, 2, or 4 g/d for 12 weeks in addition to unchanged background medication. Patients underwent assessment using the 17-item Hamilton Depression Rating Scale, the Montgomery-Asberg Depression Rating Scale, and the Beck Depression Inventory. Treatment with ethyl-eicosapentaenoate at a dosage of 1 g/d was effective in treating depression in patients who remained depressed despite adequate standard therapy.
Link to research paper: DoseStudy