Omega-3s in Mental Health Care: Part 1

Review of omega-3s for treating depressed mood

Posted Oct 10, 2017

Omega-3s: Their Emerging Role in Mental Health Care

This is part one of a two-part blog series on omega-3 fatty acids in mental health care. Below, I concisely review the evidence for omega-3s for treatment of depressed mood, including the depressive phase of bipolar disorder. In part two, I will review research highlights of studies on omega-3s for treatment of schizophrenia, dementia, and attention deficit hyperactivity disorder.

Omega-3s: What They Are and How They Work in the Body and Brain

So-called 'omega-3' fatty acids are highly polyunsaturated fatty acids that go by the chemical names eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Evidence from numerous placebo-controlled studies suggests that supplementation with omega-3s may ameliorate symptoms of depressed mood and other mental health problems. However, inconsistent results, small study sizes, and design flaws render the majority of research findings inconclusive. Different mechanisms of action have been proposed to explain the postulated antidepressant effects of omega-3 fatty acids, including increased brain serotonin activity, beneficial anti-inflammatory effects, suppression of phosphatidylinositol second messenger activity, and increased heart-rate variability (HRV). Many individuals who suffer from chronic depressed mood also have heart disease. The suppression of molecules that cause inflammation in the body—pro-inflammatory cytokines—by omega-3 fatty acids may help explain the relationship between coronary artery disease and major depressive disorder.

EPA combined with an antidepressant may help reduce the severity of depressed mood but is ineffective as a stand-alone treatment

EPA especially may help alleviate symptoms of depressed mood and can be safely used as an add-on treatment to prescription antidepressants. In contrast, DHA is probably no more effective against depressed mood than a placebo. A meta-analysis of 10 placebo-controlled, double-blind studies on omega-3 fatty acids in depressed mood lasting 4 weeks or longer concluded that EPA significantly improved depressed mood in patients diagnosed with major depressive disorder or bipolar disorder. However, there was not a consistent relationship between the dose of EPA and its effectiveness against a depressed mood. The authors of the meta-analysis concluded that publication bias and different research design methods made it impossible to confirm that EPA is effective as a stand-alone treatment of depression. Three small controlled trials have evaluated omega-3s in combination with antidepressants. In two studies, EPA (1 or 2 g per day) was added to conventional antidepressant therapy. In the third study, patients were treated with a mixture of EPA and DHA (totaling 9.6 g per day) in addition to their conventional medication. In all three studies, treatment response was significantly greater in the combined omega-3–antidepressant groups than in the antidepressant-only groups. Many patients who had failed to respond to conventional antidepressants improved markedly when they added omega-3s to their antidepressant regimen. No adverse effects were reported in the combined treatment groups or the conventional treatment groups. These findings suggest that EPA augments conventional antidepressants; however, it is too early to conclude whether EPA is an effective stand-alone therapy or whether a specific ratio of EPA to DHA has optimal antidepressant benefits.

EPA may reduce symptoms of bipolar depressed mood but not mania

A meta-analysis of placebo-controlled trials on omega-3 fatty acids in patients diagnosed with bipolar disorder identified only one study in which omega-3s used in combination with a mood stabilizer resulted in a greater beneficial effect on symptoms of depressed mood but not mania. Finally, in a four-month placebo-controlled trial, 121 rapid-cycling or depressed patients diagnosed with bipolar disorder treated with EPA (6 g per day) in combination with a conventional mood stabilizer versus placebo achieved equivalent improvements in symptoms of depressed mood but no changes in symptoms of mania.

Final words

Although promising, the majority of findings on omega-3s for the treatment of depressed mood should be regarded as preliminary pending confirmation by large well-designed placebo-controlled studies. For more about the uses of omega-3s, other natural supplements and complementary and alternative treatments of depressed mood check out my e-book, 'Depressed Mood: The Integrative Mental Health Solution." 


The Integrative Mental Health Solution, by James Lake MD