Objective: Depressive symptoms are common in Alzheimer's disease (AD) and they might influence the course and prognosis of AD. Depression could appear anytime in the course of the disease, and could either last considerably long or disappear easily. This study is intended to investigate the occurrence of depression in the course of AD and the risk factors of incidence.
Methods: This study targeted 1,272 AD patients without depressive symptoms at the start of this study in Korea. A total of 775 subjects completed the study, and the occurrence of depression was assessed after 12 months. Demographic information of subjects was collected and cognitive functions, overall functions, and depression severity were assessed at the start of this study and after 12 months.
Results: Among the 775 subjects, 103 subjects (13.29%) developed depression 12 months later. The MMSE-KC scores showed significant changes in both groups that developed depression and did not. In the univariate analysis, significant differences in the incidence of depression were found in terms of gender, the administration of the antidepressant at the baseline, the SGDS-K score, and the GDS score. The multiple logistic regression analysis showed that the increase in the incidence of depression was associated with a female, in the increase in SGDS-K score and the GDS score.
Conclusion: The incidence of depression in the subjects who completed the 12-month follow-up observation was 13.29%. Moreover, in the multivariate analysis, a female gender and the severity of dementia, including the overall functions, seemed associated with the occurrence of depression.
Keywords: Alzheimer's disease; Depression; Incidence; Risk factors.