Dr Joseph R. Hibbeln of the National Institutes of Health and Dr Simona Noaghiul of Columbia University, New York identified lifetime prevalence rates in various countries for bipolar I disorder, bipolar II disorder, bipolar spectrum disorder, and schizophrenia using population-based epidemiological studies that used similar methods.
The data was compared to differences in seafood consumption, using national statistics. The results show that greater seafood consumption predicted lower lifetime prevalence rates of bipolar I disorder, bipolar II disorder, and bipolar spectrum disorder.
Bipolar II disorder and bipolar spectrum disorder had an apparent vulnerability threshold below 50 lb of seafood/person/year. However there was no correlation between rates of schizophrenia and seafood consumption, write the researchers in this month's American Journal of Psychiatry(160:2222-2227).
Omega-3 fatty acids, found in significant amounts in oily fish and other seafood, have previously been associated with lower risk for a number of mental conditions. Recent research found that boosting levels of docosahexaenoic acid (DHA) in the blood and eating about three fish meals each week almost halved the risk of Alzheimer's disease in elderly men and women. High levels of omega-3 intake have also been linked to lower risk of depression, including post-natal depression.