Subtypes of cognitive impairment in depressed older adults.

The authors examined the cognitive profiles of 104 older adults with major depression and empirically identified three subgroups with distinct patterns of cognitive impairment. The entire sample demonstrated memory impairment relative to age-standardized scores, distributed equally across the three cognitive subgroups. One-third of subjects displayed either executive impairment or attentional deficits. The subgroup with executive dysfunction had greater behavioral disability. Identification of executive impairment in depressed older adults may facilitate intervention for disturbances in planning, sequencing, organizing, and abstracting. Demonstrating the presence of subtypes of cognitive impairments in older adults may provide the basis for further investigation of mechanisms of late-life depression and the pathophysiology of antidepressant response. The association of behavioral disability with executive dysfunction can initiate an inquiry into the biology of functional impairment ultimately linking biological research to studies of treatment effectiveness.