Most studies have shown reduced levels of polyunsaturated fatty acids, particularly docosahexaenoic acid and arachidonic acid, in the cell membranes of red blood cells from schizophrenic patients. This has led to research interest in the possible therapeutic benefits of omega-3 fatty acids in schizophrenia. There is evidence from double-blind placebo-controlled trials that omega-3 fatty acids might prevent conversion from a prodromal state into first episode psychosis, and reduce the antipsychotic drug requirement in first episode patients. Results in chronic and acutely relapsing schizophrenia have been mixed.

The problems associated with single nutrient studies are discussed. Nutrients are normally ingested in complex combinations, and they interact with each other in their normal metabolic and physiological functions.

It is likely that optimal nutritional treatment will involve complex combinations of nutrients, preferably as part of a healthy balanced diet rather than by using supplements. However, such approaches have been little evaluated in mental health.