Biological studies of DSM-III psychotic disorders. I. Platelet measures and apomorphine-induced growth hormone response.

The relationship between DSM-III schizophrenia, major affective disorders, and the psychotic disorders not elsewhere classified (PDNEC) can be explored through studies which attempt to determine whether these disorders can be differentiated from one another and normal controls by biological measures. Preliminary results of an ongoing project which utilizes measures of blood platelet monoamine oxidase (MAO), serotonin (5-HT) uptake, and 5-HT content, and the apomorphine-induced increase in growth hormone (GH) to accomplish these goals are reported here. DSM-III major affective disorders (bipolar disorder and major depression) can be differentiated from normal controls by the V max of platelet 5-HT. Platelet 5-HT V max of bipolar disorder, depressed type, is significantly different from that of schizophrenia and PDNEC. Elevated platelet 5-HT content is present in black schizophrenic patients compared to black normal controls. Platelet MAO was increased in a small group of schizophreniform female patients. There was no difference in the apomorphine-induced GH response between any of the diagnostic groups. If confirmed in a larger series of patients, these results tend to identify the PDNEC more closely with schizophrenia than the major affective disorders.