The nature and determinants of neuropsychological functioning in late-life depression.
BACKGROUND
Cognitive impairment in late-life depression (LLD) is highly prevalent, disabling, poorly understood, and likely related to long-term outcome.


OBJECTIVE
To determine the characteristics and determinants of neuropsychological functioning LLD.


METHODS
Cross-sectional study of groups of LLD patients and control subjects.


METHODS
Outpatient, university-based depression research clinic.


METHODS
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.


METHODS
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 (beta =.45-.80). Education (beta =.32) and ventricular atrophy (beta =.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.
Butters
Meryl A
MA
Department of Psychiatry, University of Pittsburgh Medical Center, PA, USA.
Whyte
Ellen M
EM
Nebes
Robert D
RD
Begley
Amy E
AE
Dew
Mary Amanda
MA
Mulsant
Benoit H
BH
Zmuda
Michelle D
MD
Bhalla
Rishi
R
Meltzer
Carolyn Cidis
CC
Pollock
Bruce G
BG
Reynolds
Charles F
CF
Becker
James T
JT
D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000553:Ambulatory Care; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000523:psychology; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012720:Severity of Illness Index