Platelet serotonin levels in schizophrenia: relationship to race and psychopathology.

To explore the possible role of serotonin (5-HT) in the etiology of schizophrenia, platelet 5-HT concentrations were determined in 41 schizophrenic (and schizoaffective, mainly schizophrenic) patients diagnosed by the RDC and 34 normal controls. There was a significant difference between the patient and control groups with the 16 paranoid, 11 undifferentiated, and 8 schizo-affective depressed patients having significantly higher mean platelet 5-HT concentrations than the controls. An analysis of variance considering the effect of race, sex, and diagnosis demonstrated a significant difference between black patients and black controls but no significant difference between white patients and white controls. Within the patient sample, platelet 5-HT concentrations were positively correlated with severity of auditory hallucinations (on the PSE) and negatively correlated with lack of insight (on the PSE) and conceptual disorganization (on the BPRS). In a subsample of 21 patients, there was no relationship between platelet 5-HT and CT findings of either enlarged ventricles or cortical atrophy.