Platelet serotonin concentration and monoamine oxidase activity in unmedicated chronic schizophrenic and in schizoaffective patients.

Elevated blood serotonin, perhaps secondary to reduced platelet MAO, has been reported in a group of chronic schizophrenic patients. We have failed to find elevated platelet serotonin, or any relationship between platelet serotonin and MAO either in a group of unmedicated chronic schizophrenic patients or in a group of schizoaffective patients. Possible reasons for these discrepancies are discussed.