Clinical factors that predict cognitive function in patients with major depression.
OBJECTIVE
To compare the performance of depressed patients to healthy control subjects on discrete cognitive domains derived from factor analysis and to examine the factors that may influence the performance of depressed patients on cognitive domains in a large sample.


METHODS
We compared the cognitive performance of 149 patients with major depression to 104 healthy control subjects using multivariate ANCOVA. We used principal component factor analysis to group the cognitive variables into cognitive domains. Finally, we conducted regression analysis to examine the contribution of predictor factors to the cognitive domains that were impaired in the depressed group.


RESULTS
Verbal memory and speed of processing were impaired in depressed patients, compared with healthy control subjects. Patient IQ, duration of depressive illness, and number of hospitalizations significantly contributed to the performance of patients on verbal memory and speed of processing. The severity of mood symptoms did not correlate with performance on any cognitive domain.


CONCLUSIONS
Understanding the factors that predict cognitive performance of patients with depression may provide an insight into the processes by which depression leads to cognitive dysfunction. Our study showed that premorbid IQ and factors related to burden of illness are strong independent predictors of cognitive dysfunction in patients with major depression.
Elgamal
Safa
S
Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario. selgamal@healthy.uwaterloo.ca
Denburg
Susan
S
Marriott
Michael
M
MacQueen
Glenda
G
D000328:Adult; D000928:Antidepressive Agents / Q000627:therapeutic use; D002170:Canada / Q000453:epidemiology; D003071:Cognition; D003710:Demography; D003863:Depression / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy / Q000523:psychology; D003865:Major Depressive Disorder / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010359:Patient Readmission; D011214:Practice, Psychological; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D014705:Verbal Behavior
D000928:Antidepressive Agents