Elevated blood serotonin concentrations in unmediated chronic schizophrenic patients: a preliminary study

The authors found higher serotonin concentrations in the blood of unmedicated chronic schizophrenic patients than in the blood of medicated schizophrenic patients or normal control subjects. This finding is consistent with the previous observation that the level of monoamine oxidase activity is low in the platelets of chronic schizophrenics.