There is evidence of increased phospholipid breakdown in cell membranes of patients suffering from schizophrenia. This may be related to increased levels of the enzyme cytosolic phospholipase A2 (cPLA2) which have been reported in schizophrenic subjects. We have identified a Ban I dimorphic site on the first intron of the cPLA2 gene. Schizophrenic subjects were found to have a significant excess of the A2/A2 homozygote relative to healthy control subjects. Genetically determined alterations in phospholipase activity may thus underlie the reported abnormalities of phospholipid metabolism in schizophrenia.