The dexamethasone suppression test in affective illnesses and schizophrenia: relationship with psychotic symptoms

The authors studied the dexamethasone suppression test (DST) on a series of 112 inpatients including 65 patients with major depressive disorder (21 bipolars: 4 with, 17 without psychotic symptoms; 44 unipolars: 13 with, 31 without psychotic symptoms), 15 patients with depressive disorder, 10 schizoaffective and 22 schizophrenic patients. Using different diagnostic criteria, they confirm the best performances of the DST in depression for the diagnosis of a major depressive disorder, primarily endogenous. They also examined the potential influence of psychotic symptoms, suicidal behavior and family history of affective illness on the DST. The only significant difference found is in the cortisol plasma level at 4 p.m. in bipolar patients with psychotic symptoms. That fact and the high rate of abnormality of the DST in schizoaffective and schizophrenic patients indicate that psychotic symptoms per se may play a role in a dysregulation of the hypothalamo-pituitary adrenal axis.