Antidepressant Exposure and Risk of Dementia in Older Adults with Major Depressive Disorder

OBJECTIVES: To identify whether duration of antidepressant use in depressed elderly veterans differed between those who later developed dementia and those who did not. DESIGN: Single-center, retrospective, observational, electronic chart review. SETTING: Medical charts from a Veterans Affairs Mental Health Clinic. PARTICIPANTS: Veterans aged 65 and older with history of depression. MEASUREMENTS: Information on sociodemographic characteristics; duration of antidepressant, antipsychotic, and benzodiazepine therapy; diagnosis of dementia; and comorbid disease states was collected. Medication use since August 1, 1998 was recorded. RESULTS: Of 1,547 charts reviewed, 605 met inclusion criteria; 128 were excluded on the basis of psychiatric comorbidities. Of the remaining 477, 41 developed incident dementia. Thirty-seven of those were matched to individuals with depression without dementia according to age, cardiovascular disease, cerebrovascular disease, diabetes mellitus, and substance use. There were no differences between the groups with (n = 37) and without (n = 37) dementia with respect to baseline characteristics, antidepressant types, or benzodiazepine or antipsychotic use. Median duration of antidepressant use was 891 days in the group with dementia and 1,979 days in the group without (P =.03, W = -260, z = -2.13). Significantly fewer participants with dementia received antidepressant treatment for at least 5 years [n = 8 with dementia, n = 20 without dementia, P =.004, odds ratio = 0.235, 95% confidence interval = 0.085-0.647). CONCLUSION: Older veterans with depression who developed dementia were treated with antidepressants for a significantly shorter duration than matched veterans who did not develop dementia.