Depression: a shared risk factor for cardiovascular and Alzheimer disease.

Depression has been linked to cardiovascular disease and cognitive impairment, including Alzheimer disease, but the exact nature of the relationship is poorly understood. Although depression seems to progress little after the onset of Alzheimer disease, depression in earlier life increases the risk of dementia and cognitive impairment many years in the future. Depression is also associated with reduced vascular function and is a poorly recognized but significant risk factor for stroke.