What does the dexamethasone suppression test identify?

The authors studied the Dexamethasone Suppression Test (DST) in chronic pain patients with and without major depression, using items from a modified version of the Hamilton Depression Scale, the Hamilton Anxiety Scale, and the Montgomery-Asberg Depression Rating Scale. The purpose of the study was to identify the factor or factors which discriminated DST suppressors from nonsuppressors. The data suggest that depression and its profile are efficient discriminators of suppressors and nonsuppressors. Anxiety-related items were not as good as discriminators. The items that identified nonsuppression were the items that are often seen in combination in endogenous depression.