The dexamethasone/corticotropin-releasing hormone test in depression in bipolar and unipolar affective illness

The combined dexamethasone/corticotropin-releasing hormone (DEX/CRH) test was performed in forty patients with depression (12 male, 28 female), aged 20-68 years, in the course of affective illness (16 bipolar, 24 unipolar) both during acute depressive episode and in remission. The results were compared with those of 20 healthy control subjects (10 male, 10 female), aged 22-52 years. During acute depressive episode, cortisol concentration at 16 h after dexamethasone, 1.5 mg, and cortisol release after subsequent infusion of CRH, 100 microg, were significantly elevated in bipolar patients compared with unipolar ones and with control subjects. Patients with multiple episodes of unipolar depression exhibited greater cortisol levels after CRH than control subjects. In remission, significantly higher cortisol concentrations measured at 30 min(-1) h after CRH infusion were found in bipolar than in unipolar patients. Male bipolar patients had significantly higher cortisol level than bipolar females before and at 1.5 h after CRH. First episode unipolar patients during remission had lower levels of cortisol than control subjects before and at 1.5 h after CRH. Correlation between the magnitude of cortisol response and age was found within unipolar depressed patients but not in bipolar ones. On the other hand, correlation of test results with intensity of depression measured by Hamilton scale as well as with insomnia and anxiety subscales was more robust in bipolar subjects than in unipolar ones. It is concluded that the dysregulation of hypothalamic-pituitary-adrenal (HPA) axis activity, detected by DEX/CRH test is significantly more marked in patients with depression in the course of bipolar affective illness than in unipolar depression. Within unipolar depression, this dysregulation may increase with the time course of the illness.