Blood Platelet Monoamine Oxidase Activity in Psychiatric Patients

The authors measured monoamine oxidase (MAO) activity in blood platelets of normal control subjects, patients with schizophrenia, and patients with other psychiatric diagnoses. No differences were found among the groups as a whole. However, in the control group, women had significantly higher enzyme activity than men. Female schizophrenic patients showed a trend toward lower activity than did female control subjects, but did not differ from the male schizophrenic patients. The authors suggest that platelet MAO activity may be related to hormonal, dietary, or genetic factors but not to psychiatric diagnosis.