Validation of four definitions of melancholia by the dexamethasone suppression test.

The authors evaluated four sets of diagnostic criteria, the Newcastle Index, DSM-III, RDC, and the Michigan Diagnostic Index, for the diagnosis of melancholia. Forty-nine depressed inpatients, all of whom met RDC for major depression, also received consensus diagnostic assessment for melancholia. The dexamethasone suppression test (DST) was administered before drug treatment began. Results showed that the sensitivity of the DST ranged from 39% to 48%, specificity from 80% to 100%, and diagnostic confidence from 66% to 100%. All four scales received validation, but DSM-III showed the lowest specificity and predictive value.