Fish oils and psychosis

Recent evidence published in Archives of General Psychiatry suggests that fish oil supplementation may reduce the risk of transition to psychotic illness in people at very high risk of these disorders.

The use of antipsychotic medication for the prevention of psychotic disorders is controversial. Long-chain omega-3 polyunsaturated fatty acids may be beneficial in a range of psychiatric conditions, including schizophrenia. Given that omega-3 polyunsaturated fatty acids are generally beneficial to health and without clinically relevant adverse effects, their preventive use in psychosis is of considerable interest.

Previous studies have found low levels of omega-3 and omega-6 polyunsaturated fatty acids in people with schizophrenia, and some scientists have suggested that problems with fatty acid metabolism could play a role in the development of the disorder. However, studies looking at the effects of omega-3 polyunsaturated fatty acid supplementation in people with schizophrenia have so far been inconclusive. Types of omega-3 fatty acids are found in oily fish, certain vegetable oils and in fish oil capsules.

A randomized, double-blind, placebo-controlled trial was conducted between 2004 and 2007 in the psychosis detection unit of a large public hospital in Vienna, Austria.

The aim was to determine whether omega-3 polyunsaturated fatty acids reduce the rate of progression to first-episode psychotic disorder in adolescents and young adults aged 13 to 25 years with subthreshold psychosis.

Eighty-one individuals at ultra-high risk of psychotic disorder participated in the trial. These participants had at least one of the following risk factors for psychosis:

• low levels of psychotic symptoms (delusions, hallucinations, suspiciousness, or conceptual disorganisation measured on a standard scale),

• transient psychosis, i.e. lasted less than a week and resolved without antipsychotic medication, or

• having either a schizotypal personality disorder or a first-degree relative (such as a mother, father, sister or brother) who had psychosis, plus the participant experienced a significant reduction in ability to function in the last year.

A 12-week intervention period of 1.2 g per day omega-3 polyunsaturated fatty acids or placebo was followed by a 40-week monitoring period; the total study period was 12 months.

Researchers monitored how much of their supplements the participants took by monitoring the number of pills they had left and by taking blood samples. The placebo pill contained coconut oil (which does not contain omega-3 polyunsaturated fatty acids) and an equivalent amount of vitamin E to the fish oil capsules, plus 1% fish oil to make the taste of the capsules similar.

Seventy-six of 81 participants (93.8%) completed the intervention. By the end of the study (12 months), 2 of 41 individuals (4.9%) in the omega-3 group and 11 of 40 (27.5%) in the placebo group had transitioned to psychotic disorder (P = .007). The difference between the groups in the cumulative risk of progression to full-threshold psychosis was 22.6% (95% confidence interval, 4.8-40.4).

Omega-3 polyunsaturated fatty acids also significantly reduced positive symptoms (P = .01), negative symptoms (P = .02), and general symptoms (P = .01) and improved functioning (P = .002) compared with placebo.

The incidence of adverse effects did not differ between the treatment groups.

The researchers concluded that:

a 12-week intervention with omega-3 significantly reduced the transition rate to psychosis and led to significant symptomatic and functional improvements during the entire follow-up period (12 months)

This small study does seem to suggest that, at least in the short term, fish oil supplementation could prevent young people at high risk from progressing to psychotic illness. However, while the study was robust in its design it was too short to say whether the illnesses were prevented completely or just delayed.

Psychotic illnesses are serious conditions and if fish oils can be confirmed to prevent or delay their development in susceptible individuals this would be a very important finding. However, it will require larger, long-term studies to know if this is the case.

To learn more about the effects of what we eat on our mental health, why not come along to a Cooking for Health course on “Food and Emotions“, taught by nutrition consultant Dr Jane Philpott.

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