Monoamine oxidase (MAO) of platelets, plasma, lymphocytes and granulocytes in schizophrenia.

Monoamine oxidase (MAO) levels in plasma, platelets, lymphocytes and granulocytes have been compared in schizophrenics and controls using three substrates. No significant difference was found between MAO levels in controls and the schizophrenic group as a whole, but platelets and lymphocytes of the latter (tyramine or benzylamine substrate) showed greater variation and in some cases higher values than controls, irrespective of treatment. Schizophrenics who experienced auditory hallucinations had significantly lower MAO levels in lymphocytes and platelets than those who did not.