Decreased blood platelet MAO activity in unmedicated chronic schizophrenic patients.

The authors found lower platelet monoamine oxidase (MAO) activity in 13 unmedicated chronic schizophrenic male patients in comparison to 13 mentally normal control male subjects--a finding that agrees with previous studies showing MAO activity to be low in the platelets of chronic schizophrenic patients. The authors urge that studies exploring endocrine factors and the role of hospitalization be undertaken to attempt to explain this finding.