|This letter reports a study on the possible relationship between high fish consumption and low annual prevalence of major depression.
Low plasma concentration of docosahexaenoic acid (which is found in fish) are associated with low concentration of an index of brain serotonin turnover, cerebrospinal fluid 5-hydroxyindolacetic acid (CSF-5-HIAA); low concentration of CSF-5-HIAA are strongly associated with depression and suicide.
An extensive dataset on prevalence of major depression and calculated data on per capita fish consumption were used.
The correlation between data for per capita annual fish consumption and annual prevalence of major depression was r = —0.84. This high correlation does not necessarily show that fish consumption can cause differences in prevalence of major depression, nor that consumption of fish or fish oil would be useful in treatment of depression.
A range of cultural, economic, social or other factors might confound this correlation.