Fish oil protects for up to seven years against psychoses


Fish oil offers protection against psychoses, concluded psychiatrists at the Medical University of Vienna a couple of years ago after doing a small study in which they gave young people at risk fish-oil capsules for 12 weeks. In a follow-up study the researchers contacted their subjects after seven years – and discovered that the protective effect of the fish oil they’d given them was still present.

About 6-7 years ago the researchers performed an experiment with 81 young people aged between 13 and 25, all of whom had a high risk of having a psychotic episode. They all showed early symptoms of psychosis.

Half of the subjects were given a placebo for a period of 12 weeks; the other half took 700 mg EPA and 480 mg DHA daily. The composition of fish oil supplements varies, but the dose the researchers used is approximately equivalent to 4 capsules containing 1 g fish oil per day.

In 2010 the researchers published the results of a study in which the subjects in the group that had been given fish oil had less frequent psychotic episodes than the subjects in the placebo group. Five years later the same researchers published a follow-up study in Nature Communications, in which they looked at how the subjects were doing 6-7 years later. They discovered that the protective effect of the supplement they’d taken was still in place.

The curves in the figure below show how many of the subjects had remained free of psychotic episodes during the period after they had taken the supplements.


The researchers used standardised questionnaires before and after they gave the subjects supplements: the Positive and Negative Syndrome Scale questionnaire [PANSS] and the Montgomery-Asberg Depression Rating Scale questionnaire [MADRS] to assess the subjects’ mental health. The lower the scores, the better your mental health.

The figure below shows that the subjects that had taken fish oil supplements still scored better than the subjects that had been given a placebo years after the supplementation had taken place.


In addition the researchers used the Global Assessment of Functioning questionnaire to assess how well the subjects functioned in everyday life. The higher the score, the better you’re doing. As you can see in the figure above, the fish-oil group scored better than the placebo group even after years.

Animal studies have shown that a diet lacking in omega-3 fatty acids results in higher activity of the enzyme tyrosine hydroxylase in the brains of young rats. [Biol Psychiatry. 2014 Jan 1;75(1):38-46.] The production of dopamine probably increases as a result of this. And too much dopamine can be the cause of psychoses. In adult rats a diet with no omega-3 fatty acids does not have this effect, by the way.

“Adolescent rats with an omega-3 PUFA-deficient diet had high levels of tyrosine hydroxylase, the enzyme responsible for catalysing the synthesis of dopamine in the dorsal striatum, essentially resembling the pattern of high dopamine activity”, the researchers wrote.

“Individuals at ultrahigh risk for psychosis have high dorsal striatal dopamine levels, which correlate positively with transition to psychotic disorders. Omega-3 PUFAs may therefore reduce conversion in subjects at risk for psychosis by preventing the pathophysiological changes associated with the increase in striatal dopamine. This finding also implies that omega-3 PUFA supplementation may be specifically effective during adolescence.”

“In conclusion, this first of its kind trial suggests that omega-3 PUFAs may offer a viable longer-term prevention strategy with minimal associated risk in young people at ultrahigh risk of psychosis”, the researchers wrote.

Longer-term outcome in the prevention of psychotic disorders by the Vienna omega-3 study.


Long-chain omega-3 polyunsaturated fatty acids (PUFAs) are essential for neural development and function. As key components of brain tissue, omega-3 PUFAs play critical roles in brain development and function, and a lack of these fatty acids has been implicated in a number of mental health conditions over the lifespan, including schizophrenia. We have previously shown that a 12-week intervention with omega-3 PUFAs reduced the risk of progression to psychotic disorder in young people with subthreshold psychotic states for a 12-month period compared with placebo. We have now completed a longer-term follow-up of this randomized, double-blind, placebo-controlled trial, at a median of 6.7 years. Here we show that brief intervention with omega-3 PUFAs reduced both the risk of progression to psychotic disorder and psychiatric morbidity in general in this study. The majority of the individuals from the omega-3 group did not show severe functional impairment and no longer experienced attenuated psychotic symptoms at follow-up.

PMID: 26263244 [PubMed – in process]