Abstract

200 mg niacin given orally causes marked facial flushing because of release of arachidonic acid and its conversion to prostaglandin D2. Normal individuals, bipolar patients and depressed patients all flush. 20-40% of unselected schizophrenic patients do not flush in this test and a preponderance of those who do not flush exhibit the negative syndrome. 69 schizophrenics from Scotland, Ireland, Poland and Australia were selected on clinical grounds as having a predominantly negative syndrome. 33 flushed in response to oral niacin and 36 did not. There were no important differences in drug treatment between the groups, indicating that flushing status was not related to drugs. However, red cell AA and DHA levels were significantly decreased and plasma AA and DHA levels were increased in the non-flushers as compared to the flushers. Both groups showed significantly decreased red cell AA and DHA as compared to control. This study confirms again that schizophrenics have reduced red cell membrane AA and DHA levels and demonstrates that the abnormality is more severe in schizophrenics who do not flush in response to oral niacin.