Evidence-Based Reviews

Omega-3 fatty acids for psychiatric illness

Current Psychiatry. 2012 September;11(9):41-46

References

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13. Mischoulon D. The impact of omega-3 fatty acids on depressive disorders and suicidality: can we reconcile 2 studies with seemingly contradictory results? J Clin Psychiatry. 2011;72(12):1574-1576.

14. Appleton KM, Rogers PJ, Andrew RN. Updated systematic review and meta-analysis of the effects of n-3 long-chain polyunsaturated fatty acids on depressed mood. Am J Clin Nutr. 2010;91(31):757-770.

15. Martins JG. EPA but not DHA appears to be responsible for the efficacy of omega-3 long chain polyunsaturated fatty acid supplementation in depression: evidence from a meta-analysis of randomized controlled trials. J Am Coll Nutr. 2009;28(5):525-542.

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18. Sacks F. Ask the expert: omega-3 fatty acids. The Nutrition Source.http://www.hsph.harvard.edu/nutritionsource/questions/omega-3/index.html. Accessed July 23 2012.

19. Sublette ME, Ellis SP, Geant AL, et al. Meta-analysis of the effects of eicosapentaenoic acid (EPA) in clinical trials in depression. J Clin Psychiatry. 2011;72(12):1577-1584.

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In a systematic review and meta-analysis, Appleton et al¹⁴ concluded that omega-3 FA supplements have little beneficial effect on depressed mood in individuals who do not have a depressive illness diagnosis (eg, MDD). However, this study did not consider the differential effects of EPA vs DHA on treatment response. Patients diagnosed with a depressive illness received greater benefits from omega-3 FA supplementation, although the patients in this study were heterogeneous. Similar to Bloch and Hannestad, Appleton et al¹⁴ found that omega-3 FA supplementation may be most beneficial for depressed patients with more severe symptoms, but is unlikely to help those with mild-to-moderate symptoms or individuals without symptoms who aim to prevent depression.

Clinical Point

Omega-3 FAs may be most beneficial for depressed patients with more severe symptoms

A meta-analysis by Martins¹⁵ looked at EPA vs DHA to treat depressive illness and found that only supplements that were mostly or completely EPA effectively treated depressive symptoms. Martins also found that severity of illness is key for positive treatment outcomes; there was a significant relationship between higher baseline depression levels and efficacy.¹⁵ Martins noted that omega-3 FA therapy was more effective as a treatment than a preventive strategy, and that adding omega-3 FAs to antidepressants was more efficacious than omega-3 FAs alone.¹⁵

Clinical Point

A meta-analysis found only supplements that were mostly or entirely EPA effectively treated depressive symptoms

A meta-analysis of clinical trials of omega-3 FAs for depressive illness suggested EPA should be ≥60% of total EPA + DHA.¹⁶

BD. A recent meta-analysis of 6 randomized controlled trials (RCTs) found that adding omega-3 supplements to mood stabilizers in patients with BD was associated with a statistically significant reduction of depressive symptoms, but was not effective for treating mania.¹⁷ The authors suggested patients with BD—especially those with comorbid cardiovascular or metabolic conditions— increase their dietary consumption of foods containing omega-3 FAs (Table)¹⁸ and, if necessary, take a supplement of 1 to 1.5 g/d of mixed EPA and DHA, with a higher ratio of EPA.¹⁹ See Box 3 for a box on how to read omega-3 supplement labels.

In a small RCT of 51 children and adolescents (age 6 to 17) with symptomatic bipolar I or bipolar II disorder, supplementation with flax oil (alpha-linolenic acid, a polyunsaturated omega-3 FA that is a precursor to EPA and DHA) did not affect symptoms as measured by several rating scales.²⁰

Perinatal and postpartum depression. Omega-3 FAs are considered a safe treatment for depressive disorders during pregnancy because they provide neurodevelopmental benefits for neonates and have few contraindications during pregnancy.²¹ RCTs of omega-3 FA monotherapy for perinatal depression have been small (≤51 patients) and produced mixed findings.²¹ A pilot study (N = 16) of patients with postpartum depression found a significant decrease in depressive symptoms with EPA treatment.²² More research is needed before omega-3 FA supplementation can be recommended during pregnancy.

Table

Foods with healthy fats: From best to worst

Polyunsaturated fats	Omega-3	Fish-based: oily fish, including salmon, tuna, mackerel, lake trout, herring, and sardines Plant-based: tofu and other forms of soybeans; walnuts and flaxseed and their oils, and canola oil
Polyunsaturated fats	Omega-6	Only available in plant-based form: corn, soy, and safflower oil
Monosaturated fats		Olive and peanut oil
Saturated fats		Red meats, high-fat dairy, and partially hydrogenated oils
Source: Reference 18

Box 3

Selecting an omega-3 supplement: What to tell patients

Because nutritional supplements vary, advise patients to look at the supplement facts on the back of a bottle of omega-3 fatty acids. The American Psychiatric Association recommends patients take a total eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) of 1 g/d; EPA should be ≥60% of total EPA + DHA.

This image is an example of a label that would meet the appropriate criteria. Total EPA + DHA = 1,490 mg and EPA is 60% of this combined total.

Source: Sublette ME, Ellis SP, Geant AL, et al. Meta-analysis of the effects of eicosapentaenoic acid (EPA) in clinical trials in depression. J Clin Psychiatry. 2011;72(12):1577-1584

Schizophrenia

In a Cochrane review of 8 studies of patients with schizophrenia, adjunctive treatment with omega-3 FAs led to >25% reduction in the Positive and Negative Syndrome Scale, but this improvement was not statistically significant.²³ Omega-3 FAs did not decrease tardive dyskinesia symptoms as measured by the Abnormal Involuntary Movement Scale. The authors stated that results were inconclusive, and use of omega-3 FAs in patients with schizophrenia remains experimental. In a separate meta-analysis that included 335 patients with schizophrenia, EPA augmentation had no beneficial effect on psychotic symptoms.²⁴

Clinical Point

In schizophrenia, adjunctive omega-3 FAs led to >25% reduction in PANSS scores, but this was not statistically significant