Food and Behaviour Research

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Omega-3 fatty acids: evidence basis for treatment and future research in psychiatry

Freeman MP, Hibbeln JR, Wisner KL, Davis JM, Mischoulon D, Peet M, Keck PE Jr, Marangell LB, Richardson AJ, Lake J, Stoll AL. (2006) The Journal of Clinical Psychiatry 67(12): 1954-67 

Web URL: View this abstract via PubMed here

Abstract:

OBJECTIVE: To determine if the available data support the use of omega-3 essential fatty acids (EFA) for clinical use in the prevention and/or treatment of psychiatric disorders.

PARTICIPANTS: The authors of this article were invited participants in the Omega-3 Fatty Acids Subcommittee, assembled by the Committee on Research on Psychiatric Treatments of the American Psychiatric Association (APA).

EVIDENCE: Published literature and data presented at scientific meetings were reviewed. Specific disorders reviewed included major depressive disorder, bipolar disorder, schizophrenia, dementia, borderline personality disorder and impulsivity, and attention-deficit/hyperactivity disorder. Meta-analyses were conducted in major depressive and bipolar disorders and schizophrenia, as sufficient data were available to conduct such analyses in these areas of interest.

CONSENSUS PROCESS: The subcommittee prepared the manuscript, which was reviewed and approved by the following APA committees: the Committee on Research on Psychiatric Treatments, the Council on Research, and the Joint Reference Committee.

CONCLUSIONS: The preponderance of epidemiologic and tissue compositional studies supports a protective effect of omega-3 EFA intake, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in mood disorders. Meta-analyses of randomized controlled trials demonstrate a statistically significant benefit in unipolar and bipolar depression (p = .02). The results were highly heterogeneous, indicating that it is important to examine the characteristics of each individual study to note the differences in design and execution. There is less evidence of benefit in schizophrenia. EPA and DHA appear to have negligible risks and some potential benefit in major depressive disorder and bipolar disorder, but results remain inconclusive in most areas of interest in psychiatry. Treatment recommendations and directions for future research are described. Health benefits of omega-3 EFA may be especially important in patients with psychiatric disorders, due to high prevalence rates of smoking and obesity and the metabolic side effects of some psychotropic medications.

FAB RESEARCH COMMENT:

This timely new review, supported by the American Psychiatric Association (APA), summarises for clinicians both the theory and the available evidence that omega-3 fatty acids may help in the prevention and management of a wide range of psychiatric disorders.

Importantly, it summarises evidence from epidemiological (population), experimental and clinical treatment trials to give a far more complete picture than most conventional systematic reviews or 'meta-analyses'. The latter were also performed, however, in areas where there was sufficient evidence from randomized controlled trials to merit this.

The APA committee made the following specific treatment recommendations on the basis of the available evidence:

  • all adults should eat fish at least 2 x week
  • patients with mood, impulse control or psychotic disorders should consume 1g/day of EPA + DHA (the omega-3 found in fish oils)
  • a supplement may be useful in patients with mood disorders (1-9g/day). Use of > 3g/day should be monitored by a physician.

It was emphasised that these dietary recommendations are *not* intended as a substitute for standard treatments for psychiatric disorders, but as a complement to these.

The meta-analysis of 8 studies involving patients with depression or bipolar disorder showed overall significant benefits from omega-3 treatment (p < 0.03) although there was considerable variability between studies. This indicates the need to consider differences between study populations as well as doses and ratios of EPA:DHA used. It was noted that most positive trials used EPA primarily or exclusively, rather than DHA.

For schizophrenia, meta-analysis of 4 trials showed no overall benefits for psychotic symptoms, and less variability between studies. Here, however, it was noted that the physical health benefits of omega-3 may help to mitigate the increased risks of cardiovascular disease and diabetes associated with schizophrenia, which some antipsychotic medications can exacerbate.

It was also noted that while omega-3 may have benefits for various disorders involving poor impulse control (such as ADHD and some personality disorders), existing evidence was insufficient to support additional treatment recommendations, but the need for further research in these and other areas of psychiatry was emphasised.