Diagnostic performance of basal free cortisol/18-hydroxy-11-deoxycorticosterone (18-OH-DOC) ratio in endogenous depression: comparison with the dexamethasone suppression test.

We assessed the 8:00 AM ratio of free cortisol/18-hydroxy-11-deoxycorticosterone (18-OH-DOC) in 56 endogenous depressive inpatients and in 22 normal volunteers. A ratio higher than 40 was associated with a diagnostic sensitivity for endogenous depression of 75%, a specificity of 95.5%, and a diagnostic confidence of 97.7%. These diagnostic results were at least equivalent to the Dexamethasone Suppression Test (DST) using a cortisol cut-off limit of 5 micrograms/dl. This may thus represent a simpler procedure than the DST in the diagnostic analysis of endogenous depression.