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Polyunsaturated fatty acid supplementation for schizophreniaJoy CB, Mumby-Croft R, Joy LA
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SummarySchizophrenia is a serious, chronic and relapsing mental illness with a worldwide lifetime prevalence of approximately 1%. Early research suggests dietary supplementation with essential fatty acids (EFAs) may have a positive effect on the symptoms of schizophrenia. We systematically reviewed the effects of EFA supplementation for those suffering from schizophrenia. We included six studies involving 353 people. Results show one particular type of EFA, ethyl eicosapentaenoic acid (an omega-3 EFA) may have a positive effect on mental state but, at the moment, results are inconclusive due to the limited number of studies and lack of usable data within these studies.
This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2008 Issue 2, Copyright © 2008 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This version first published online:
January 25. 1999 AbstractBackgroundLimited evidence supports a hypothesis suggesting that schizophrenic symptoms may be the result of altered neuronal membrane structure and metabolism. The structure and metabolism is dependent on blood plasma levels of certain essential fatty acids and their metabolites. ObjectivesTo review the effects of polyunsaturated fatty acids for people with schizophrenia. Search strategyWe have updated the initial searches of 1998 and 2002 (Cochrane Schizophrenia Group's Register, July 2005), and where necessary, we contacted authors and relevant pharmaceutical companies. Selection criteriaWe included all randomised clinical trials of polyunsaturated fatty acid treatment for schizophrenia. Data collection and analysisWorking independently, we selected studies for quality assessment and extracted relevant data. We analysed on an intention-to-treat basis. Where possible and appropriate we calculated the Relative Risk (RR) and their 95% confidence intervals (CI) and estimated the number needed to treat (NNT). For continuous data we calculated weighted mean differences (WMD) and their 95% confidence intervals. We also inspected the data for heterogeneity. Main resultsWhen any dose omega-3 (E-EPA or EPA) is compared with placebo, small short trials suggest that the need for neuroleptics appears to be reduced for people allocated omega-3 supplementation (n=30, 1 RCT, RR 0.73 CI 0.54 to 1.00) and mental state may improve (n=30, 1 RCT, RR not gaining 25% change in PANSS scores 0.54 CI 0.30 to 0.96, NNT3 CI 2-29). There are no differences in the number of people leaving the study early (n=271, 4 RCTs, RR 0.91 CI 0.36 to 2.33). There are few data on the comparison of any dose omega-6 (GLA) with placebo. For movement disorder outcomes, the only small study we found does not show any difference for average short-term endpoint AIMS score (n=16, 1 RCT, MD 1.30 CI -1.96 to 4.56). When any dose omega 3 (E-EPA or EPA) is compared with any dose omega-3 (DHA) there is no clear difference for mental state outcome of not gaining 25% change in PANSS scores (n=31, 1 RCT, RR 0.66 CI 0.39 to 1.11). When different doses of omega-3 (E-EPA) are compared with placebo there are no differences in measures of global and mental state between the studies. For the outcome of 'experiencing at least one adverse effect' no differences between groups are found for any dose (1g/day E-EPA vs placebo n=63 1 RCT, RR 0.97 CI 0.60 to 1.56; 2g/day E-EPA vs placebo n=63 1 RCT, RR 0.67 CI 0.37 to 1.20; 4g/day E-EPA vs placebo n=58, 1 RCT, RR 1.15 CI 0.72 to 1.82). Authors' conclusionsTwo updates of this review have resulted in more included studies but relatively little useful additional data. The results remain inconclusive. The new trials all compare the omega-3 polyunsaturated fatty acids, in particular eicosapentaenoic acid and its ester, ethyl-eicosapentaenoic acid. The use of omega-3 polyunsaturated fatty acids for schizophrenia still remains experimental and this review highlights the need for large well designed, conducted and reported studies. |