High potency fish oil can be used for the treatment of mild to moderate depression, or to help prevent and treat postpartum depression. Several studies have determined that a higher ratio of EPA to DHA is actually the most effective for the treatment of depression.
EPA For Depression
An 8-week trial examining the short-term efficacy of omega 3 fatty acids in patients with major depressive episodes (MDE) was conducted. Patients in the treatment group received 1050 mg/d of EPA and 150 mg/d DHA, with the control group receiving a placebo. Researchers found that for patients with MDE, the omega 3 supplementation was superior to placebo for symptom improvement. In patients with anxiety and MDE, the omega 3 supplementation was not found to be statistically significantly beneficial. A study comparing omega 3 fatty acids, as monotherapy and in combination with fluoxetine (an antidepressant), examined patients' depressive symptoms and their cortisol levels. Patients received either 1000 mg EPA, 20 mg fluoxetine, or both, for 8 weeks. Plasma cortisol (stress hormone) levels decreased in all 3 treatment groups, without a significant difference between the 3 groups. This suggests that the therapeutic effect of EPA may be exerted through its ability to lower cortisol levels.
Depression In Elderly
A placebo-controlled double-blinded study was performed for elderly women between 66–95 years of age with symptoms of depression. Women were given either 1.67 g/d of EPA and 0.83 g/d of DHA or placebo. Results were based on an improvement in depression symptoms based on the Geriatric Depression Scale after 8 weeks of treatment. Researchers concluded that the omega 3 supplementation was effective for improving symptoms of depression as well as quality of life in elderly female patients.
Depression In Heart Disease
The leading cause of mortality for patients with major depression is coronary heart disease. Patients who have experienced a cardiovascular event are also more likely to experience major depression and an increased risk of mortality. Researchers have proposed that a deficiency of omega 3 fatty acids plays a role in the pathology of both cardiovascular disease and major depression. After an acute coronary event (ACE), patients who developed depression had lower serum levels of omega 3 fatty acids than patients who did not experience depression after an ACE. Prospective studies have found that the lower the dietary or membrane levels of EPA and DHA, the higher the risk for both major depression and cardiovascular disease. This area needs further research but it does provide a strong amount of evidence to warrant exploring the effect of increasing the omega 3 status of patients with cardiovascular disease or major depression.
A study examined the effect of the combination of omega 3s and sertraline for treatment of patients with depression and coronary heart disease. The study was a randomized, double-blind study where all patients were given 50 mg/d sertaline (an antidepressant), and either 2 g/day of omega 3—930 mg EPA and 750 mg DHA—for 10 weeks, or placebo. Outcome was measured using the Beck Depression Inventory and the Hamilton Rating Scale for Depression. No significant differences were noted between the groups. In a study using a 1:4 ratio of EPA (420 mg):DHA(1680 mg) per day for 6 weeks in women with perinatal depression, researchers found no benefit from the therapy for these women. These studies suggest that supplementation of lower ratios of EPA:DHA is not effective for the treatment of depression, and highlights the importance of high-ratio EPA:DHA omega 3 supplementation in this population.
In a review article exploring the data of omega 3 supplementation and its benefit on depression, the authors investigated whether EPA or DHA or both are the beneficial component of the omega 3 supplement. The summary of the meta-analysis found that EPA was likely more efficacious than DHA in the treatment of depression.
Depression during pregnancy is quite common and treatment can be challenging. As fetal demand of omega 3 fatty acids remains very high during pregnancy, the associated decrease in the mother may leave them prone to depression. A study exploring monotherapy for the treatment of depression during pregnancy was performed. The study was an 8 week double-blind, placebo-controlled comparing the treatment with 2.2 g/d EPA and 1.2 g/d DHA to placebo for major depressive disorder in pregnancy. At the end of the study, subjects on the omega 3 treatment had significantly lower depressive symptoms than subjects consuming the control group. Also important to note was that the treatment was well tolerated and there were no adverse effects on either the women or newborns.
In a study in women with postpartum depression (PPD), subjects were given either 0.5 g, 1.4 g or 2.8 g/d of a 1.5:1 ratio EPA:DHA supplement for 8 weeks. Women were assessed before and after treatment with the Edinburgh Postnatal Depression Scale and the Hamilton Rating Scale for Depression. Before treatment, the mean scores were 18 and 19, while the after-treatment mean scores were 9 and 10 (a big improvement). It has emerged in the scientific literature that oral supplementation of omega 3 fatty acids in higher ratios of EPA:DHA are more effective than lower ratios for the treatment of depression. While EPA:DHA ratio may not play as important a role in cardiovascular protection or the mitigation of inflammation, there is a need for this specificity in the treatment of depression, and possibly in other mental emotional, psychological or psychiatric conditions.