The dexamethasone suppression test in dementia.

The dexamethasone suppression test (DST) was performed on 13 patients with multi-infarct dementia (MID), 5 patients with primary degenerative dementia (PDD) and 18 elderly controls. Abnormal lack of suppression was found in 7 demented patients (3 with PDD, 1 mild and 2 severe, and 4 with MID, 1 mild and 3 severe), and in 2 of the controls. Only one demented patient was depressed. The value of DST in the differential diagnosis of dementia from the major depressive disorders is discussed.