Med-Psych.com

I was doing some reading today on early interventions for schizophrenia and some disappointing news from one of the studies, when I thought back to the study on fish oil and schizophrenia I had commented on back in february.

That study was a prospective study in people identified as being at high risk of developing psychosis. One group was randomized to received omega-3 fatty acids (fish oil) and the other group received a placebo. The fish oil group had significantly fewer people develop psychosis at the end of the study.

I'm very interested in this finding and whether it can be replicated because it would be a real advance in psychiatry. I haven't really heard much buzz about this, but that shouldnt' surprise me since no big pharmaceutical company is sponsoring the study (as far as I know).

I figured I would do a little digging to see if there have been any follow-up studies or other studies to support the theory. The only article I found to seem relavent while doing a pubmed search was:

Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33 000 women from the general population

You can read the entire study online at the above link. To summarize, the authors looked at a large group of women prospectively. They started with over 30,000 women between the ages of 30 and 50 and had them complete a questionnaire on their diet. They then had them complete a questionnaire that was used to determine presence of psychotic symptoms. 817 of the women were identified as having a high level of psychotic symptoms.

They found that among women who ate fish 3-4 times per week compared to those who never ate fish, there was a 53% lower chance of having a high level of psychotic symptoms. The risk was also lower for women with high intake of omega-3 and omega-6 polyunsaturated fatty acids (PUFA). Interestingly, the effect was most pronounced for omega-6 PUFAs.

The findings get a big confusing though. It seems that an intermediate intake of fish was better than a high intake of fish. They specify that those who ate fatty fish (herring/mackerel, salmon-type fish), the intermediate intake seemed to be protective of psychotic symptoms, but high intake of fatty fish (more than twice a week) actually had a significantly increased risk of pschotic symptoms. They also note that people who had high intake of vitamin D consumption had a 37% lower risk of psychotic-like symptoms.

I'm not sure what to make of these findings. Some fish may be better than others, but too much of some types of fish may actually be worse.