Context: Prospective studies have established an association between depressive symptoms and risk of dementia, but how depressive symptoms change during the evolution of dementia is uncertain.
Objective: To test the hypothesis that depressive symptoms increase during the prodromal phase of Alzheimer disease (AD).
Design: Prospective cohort study.
Participants and setting: For up to 13 years, 917 older Catholic nuns, priests, and monks without dementia at study onset completed annual clinical evaluations that included administration of the 10-item Center for Epidemiologic Studies Depression Scale and clinical classification of mild cognitive impairment and AD.
Main outcome measure: Change in depressive symptoms reported on the Center for Epidemiologic Studies Depression Scale.
Results: At baseline, participants reported a mean (SD) of 1.0 (1.5) depressive symptoms. Those who developed AD (n = 190) showed no increase in depressive symptoms before the diagnosis was made, and this finding was not modified by age, sex, education, memory complaints, vascular burden, or personality. There was no systematic change in depressive symptoms after the AD diagnosis, although symptoms tended to decrease in women relative to men and in those with a higher premorbid level of openness and a lower premorbid level of agreeableness. Among those without cognitive impairment at baseline, depressive symptoms did not increase in those who subsequently developed mild cognitive impairment.
Conclusion: We found no evidence of an increase in depressive symptoms during the prodromal phase of AD.