The dexamethasone suppression test in depressive, non-depressive and schizoaffective psychosis.

The authors examined the 24-h plasma cortisol response to dexamethasone in 19 patients with co-existing depressive and psychotic features and in 12 non-depressed patients with only psychotic features. The rate and degree of abnormal dexamethasone suppression was greatest in patients who met RDC criteria for primary depressive disorder. Patients who met criteria for schizoaffective--mainly schizophrenic--depressed and other psychotic disorders did not differ from each other in their response to dexamethasone. These data suggest that the DST may have utility in the diagnostic evaluation of some patients with depressive and psychotic features.