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Late-life depression (LLD, major depression occurring in an adult 60 years or older) is a common condition that frequently presents with cognitive impairment. Up to half of individuals with LLD are estimated to have cognitive impairment greater than that of age- and education-matched comparators, with impairments of episodic memory, speed of information processing, executive functioning, and visuospatial ability being most common. To inform our understanding of the state- versus trait-effects of depression on neuropsychological functioning, and to overcome limitations of previous studies, we utilized baseline data from the longitudinal Pathways study to compare differences in single time point performance on a broad-based neuropsychological battery across three diagnostic groups of older adults, each comprised of unique participants (n = 438): currently depressed (n = 120), previously depressed but currently euthymic (n = 190), and never-depressed (n = 128). Consistent with our hypotheses, we found that participants with a history of depression (currently or previously depressed) performed significantly worse than never-depressed participants on most tests of global cognition, as well as on tests of episodic memory, attention and processing speed, verbal ability, and visuospatial ability; in general, differences were most pronounced within the domain of attention and processing speed. Contrary to our hypothesis, we did not observe differences in executive performance between the two depression groups, suggesting that certain aspects of executive functioning are "trait deficits" associated with LLD. These findings are in general agreement with the existing literature, and represent an enhancement in methodological rigor over previous studies given the cross-sectional approach that avoids practice effects on test performance.

Context Cognitive impairment in late-life depression (LLD) is highly prevalent, disabling, poorly understood, and likely related to long-term outcome. Objectives To determine the characteristics and determinants of neuropsychological functioning LLD. Design Cross-sectional study of groups of LLD patients and control subjects. Setting Outpatient, university-based depression research clinic. Participants One hundred patients without dementia 60 years and older who met DSM-IV criteria for current episode of unipolar major depression (nonpsychotic) and 40 nondepressed, age- and education-equated control subjects. Main Outcome Measures A comprehensive neuropsychological battery. Results Relative to control subjects, LLD patients performed poorer in all cognitive domains. More than half exhibited significant impairment (performance below the 10th percentile of the control group). Information processing speed and visuospatial and executive abilities were the most broadly and frequently impaired. The neuropsychological impairments were mediated almost entirely by slowed information processing (β = .45-.80). Education (β = .32) and ventricular atrophy (β = .28) made additional modest contributions to variance in measures of language ability. Medical and vascular disease burden, apolipoprotein E genotype, and serum anticholinergicity did not contribute to variance in any cognitive domain. Conclusions Late-life depression is characterized by slowed information processing, which affects all realms of cognition. This supports the concept that frontostriatal dysfunction plays a key role in LLD. The putative role of some risk factors was validated (eg, advanced age, low education, depression severity), whereas others were not (eg, medical burden, age at onset of first depressive episode). Further studies of neuropsychological functioning in remitted LLD patients are needed to parse episode-related and persistent factors and to relate them to underlying neural dysfunction. [ABSTRACT FROM AUTHOR]