THE DIFFERENTIATION OF MAJOR DEPRESSION FROM DEMENTIA OF THE ALZHEIMER-TYPE USING WITHIN-SUBJECT NEUROPSYCHOLOGICAL DISCREPANCY ANALYSIS

The method of comparing premorbid versus current intellectual ability has become established clinical practice in the differential diagnosis of dementia versus depression. Recently, Schlosser & Ivison (1989) su ggested that the comparison of premorbid ability versus current memory function may offer a more sensitive method of assessing early dementi a. In the present study, a variety of within-subject discrepancy analy ses comparing premorbid estimates with current measures of memory and intellectual functioning were compared across three groups: patients w ith dementia of the Alzheimer type, patients with major depression and healthy controls. The results revealed that, while mean group differe nces were easily demonstrated, the overlap between Alzheimer and depre ssed patients was large. It is concluded that none of the simple neuro psychological discrepancy analyses examined in the present study can b e recommended for use in clinical practice for the differential diagno sis of dementia from major depression.