Depressive symptoms among cognitively normal versus cognitively impaired elderly subjects

The present cross-sectional study analyzed the prevalence and severity of depressive symptoms among patients with Alzheimer's disease (DAT), vascular dementia (VAD), and among the cognitively normal elderly. Putative risk factors contributing to depression were likewise evaluated.

Seventy-six DAT patients, 51 VAD patients, and 121 cognitively normal subjects were admitted to the study. Questionnaires concerning demography and their vascular and familial risk factors together with results of neuropsychological testing by combined Mini-Mental Status Examinations (MMSE), Cognitive Capacity Screening Examinations (CCSE), and Hamilton Depression Rating Scales (HDRS) were obtained so that resulting data would be statistically analyzed.

Prevalence of depressive symptoms among VAD, DAT, and cognitively normal elderly were 31.4%, 19.9%, and 13.2%, respectively. 25.5% of VAD and 13.2% of DAT patients had depression of mild to moderate degrees. Regression analysis revealed that diagnosis of VAD and DAT, heart disease, and past history of depression was significantly associated with high HDRS scores. There was no correlation between degree of depression and severity of cognitive impairments.

Mild to moderate depression is a common comorbidity with organic dementia, especially VAD, but associated depression is independent of severity of cognitive impairments.