AbstractIn a controlled study of red cell membrane fatty acids in patients with schizophrenia, substantial depletions of fatty acids from both the n‐6 and n‐3 series were demonstrated. Arachidonic acid and docosahexaenoic acid were particularly depleted. In a separate study, dietary analysis revealed no deficiency of fatty acid intake in this patient group, but greater intake of n‐3 fatty acids was associated with less severe symptomatology. Dietary supplementation for six weeks with 10 g per day of concentrated fish oil (MaxEPA) led to significant improvement in schizophrenic symptoms. This clinical improvement was related to the increased level of n‐3 fatty acids in red cell membranes. These findings form part of a growing body of research data suggestive of an abnormality in cell membrane fatty acid composition in schizophrenia. The preliminary evidence for clinically effective dietary manipulation to correct such an abnormality opens up novel and exciting therapeutic possibilities.