Table 4.

Studies investigating the association between depression, dementia, and AD.

Study	Study design	Main results
Alzheimer's disease
Kokmen et al. (1991)	Population-based case-control study	Episodic depression associated positively with AD
Devanand et al. (1996)	Prospective longitudinal study	Depressed mood moderately increased the risk for AD
Green et al. (2003)	Cross-sectional, case-control study	Depression symptoms may occur 25 years before the onset of AD
Ownby et al. (2006)	Systematic review, meta-analysis	Depression associated with an increased risk of AD
Dementia
Speck et al. (1995)	Case-control study	Depression may occur 10 years before the onset of dementia
Buntinx et al. (1996)	Retrospective cohort study	Old age depression may be a predictor of subsequent dementia