Increased whole blood serotonin concentrations in chronic schizophrenic patients.

Whole blood serotonin concentrations were studied in 33 chronic schizophrenic patients who previously had computed tomographic (CT) brain scans and in 23 healthy volunteers. The chronic schizophrenic patients had a mean serotonin concentration significantly higher than that of the controls. The patients were subcategorized into a group with abnormal CT scan findings (enlargement of cerebral ventricles, cerebral atrophy, or both) and a group with normal CT scans. The patients with abnormal CT scans had significantly higher serotonin concentrations when compared with schizophrenics with normal CT scans and with controls. The chronic schizophrenic patients with normal CT scans did not have significantly elevated serotonin concentrations compared with controls. Furthermore, ventricular size in the total group was significantly correlated with serotonin concentration.