Patterns of Mild Cognitive Impairment After Treatment of Depression in the Elderly

Abstract

Late-life depression (LLD) is associated with persistent cognitive impairment in a subset of individuals. The purpose of this study was to 1) examine the frequency and characteristics of cognitive diagnoses (Mild Cognitive Impairment [MCI], dementia) among remitted elderly depressed subjects and 2) to compare the prevalence rate and correlates of cognitive diagnoses with those of comparison subjects. Crosssectional. Outpatient geriatric mental health clinic. The authors examined cognitive diagnoses among 109 subjects age 65 and older, after depression treatment response and 65 never-depressed, age- and education-equated comparison subjects. Cognitive diagnoses were independently established by the University of Pittsburgh's Alzheimer's Disease Research Center. Bivariate and multivariate analyses were conducted to examine the role of specific risk factors for cognitive diagnosis among depressed subjects. Relative to comparison subjects, nearly twice as many depressed subjects were diagnosed with MCI or dementia (48% versus 28%). Of the 109 depressed subjects, 38% were diagnosed with MCI (63% amnestic, 37% nonamnestic). The majority of amnestic MCI subjects (85%) had the multiple domain subtype. Age, but not age of onset or lifetime depression duration, predicted cognitive diagnosis. Despite adequate depression treatment response, 48% of remitted depressed subjects had a cognitive diagnosis. Of the 38% diagnosed with MCI, there was high representation among both the amnestic and the nonamnestic subtypes, suggesting heterogeneity in cognitive course and outcomes in LLD.