Abstract
This study compares the utility of a cortisol suppression index with the standard dexamethasone suppression test as a diagnostic aid for major depressive disorder. In 50 patients the cortisol suppression index was found to have similar sensitivity while also having greater specificity and diagnostic confidence than the dexamethasone suppression test. By avoiding the need for a late-evening blood sample, the cortisol suppression index may be an acceptable alternative to the current procedure.