Evidence-Based Reviews

Omega-3 fatty acids: Do ‘fish oils’ have a therapeutic role in psychiatry?

Current Psychiatry. 2004 January;3(1):25-52

References

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16. Marangell LB, Martinez JM, Zboyan HA, et al. A double-blind, placebo-controlled study of the omega-3 fatty acid docosahexaenoic acid in the treatment of major depression. Am J Psychiatry 2003;160(5):996-8.

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18. Chiu CC, Huang SY, Su KP, et al. Polyunsaturated fatty acid deficit in patients with bipolar disorder. Eur Neuropsychopharmacol 2003;13(2):99-103.

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Controlled trials, adjunctive therapy

Peet et al. ²⁶ In a 3-month study, 45 patients with schizophrenia were randomly assigned to adjunctive EPA or DHA (2 grams/d) or placebo. Those receiving EPA showed significantly greater improvement as measured by the Positive and Negative Syndrome Scale (PANSS), compared with DHA or placebo.
Fenton et al. ²⁷ In a 16-week study, 87 patients with schizophrenia or schizoaffective disorder were randomly assigned to adjunctive ethyl-EPA, 3 grams/d, or placebo. Little difference was noted in outcome measures of psychotic symptoms, mood, cognition, or extrapyramidal symptoms.
Peet et al. ²⁸ In a 12-week study. 115 patients with schizophrenia receiving typical antipsychotics, clozapine, or other atypical antipsychotics were randomly assigned to adjunctive ethyl-EPA (1, 2, or 4 grams/d) or placebo. Those taking clozapine improved significantly more with 2 grams/d of ethyl-EPA compared with patients receiving placebo. Little difference was noted between ethyl-EPA and placebo among patients taking typical or atypical antipsychotics.
Emsley et al. ²⁹ Forty patients with schizophrenia were randomly assigned to adjunctive ethyl-EPA, 3 grams/d, or placebo across 12 weeks. The ethyl-EPA group showed greater improvement in total PANSS scores and reduced dyskinesia, compared with placebo. Further analysis suggested, however, that the reduced dyskinesia scores at least partially accounted for the PANSS changes.

Controlled trial, monotherapy

Peet et al. ²⁶ Twenty-six patients with schizophrenia were randomly assigned to EPA, 2 grams/d, or placebo. After 3 months, those receiving EPA had significantly lower PANSS scores, and fewer (8 of 14) required antipsychotics than did those receiving placebo (12 of 12).

Analysis. Adjunctive ethyl-EPA (and perhaps combinations of EPA and DHA) may help patients with schizophrenia who are taking typical or atypical antipsychotics. EPA monotherapy also may be useful. Data are limited, however, and studies are needed before such use could be recommended.

Treating other disorders

Postpartum depression. The developing fetus and neonate require DHA from maternal stores for neurologic development. Maternal DHA depletion³⁰ has been hypothesized to put mothers at risk for postpartum depression.³¹ An ecological study with data from 23 countries found that higher concentrations of DHA in maternal breast milk and greater seafood consumption predicted lower postpartum depression rates.³²

In a randomized, controlled trial, giving DHA, 200 mg/d, to breastfeeding women during the first 4 months postpartum increased maternal plasma phospholipid content by 8%, compared with a 31% decrease in women given placebo.³³

Data from randomized, controlled trials are needed to assess whether omega-3 fatty acid supplementation during pregnancy and the postpartum protects against postpartum depression.

Borderline personality disorder. In an 8-week controlled trial, Zanarini and Frankenburg³⁴ randomly assigned 20 subjects with borderline personality disorder to monotherapy with ethyl-EPA, 1 gram/d, or placebo. Depressive symptoms improved and aggression decreased significantly in the ethyl-EPA group, suggesting the need for further research.

ADHD. Low DHA levels have been found in serum³⁵ and erythrocytes³⁶ of hyperactive children when compared with controls. Limited data in boys ages 6 to 12 also suggest an inverse relationship between plasma omega-3 fatty acids and behavior problems, as measured by the Connors’ Rating Scale.³⁷

More research is needed into omega-3 fatty acids’ potential role in treating attention-deficit/hyperactivity disorder (ADHD), even though results of one controlled trial of adjunctive DHA in ADHD were disappointing.³⁸

Dementia. Some large, prospective, epidemiologic studies^39-41—but not others⁴²—found an inverse relationship between dietary intake of omega-3 fatty acids and risk of cognitive decline or dementia.

Related resources

USDA Nutrient Data Laboratory. http://www.nalusda.gov/fnic/foodcomp (accessed Dec. 1, 2003)
Stoll AL. The omega-3 connection: the groundbreaking omega-3 antidepression diet and brain program. New York: Simon and Schuster, 2001.

Drug brand names

Clozapine • Clozaril

Disclosure

The authors report no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.