Is depression a risk factor for dementia or cognitive decline?

Abstract

Background: It is generally accepted that depression can be associated with significant cognitive deficits and that depression can be comorbid with dementia. Objective: This review seeks to go further and ask whether depression earlier in life can be a risk factor for subsequent dementia or for cognitive decline. Methods: A review was made of the epidemiological evidence from case-control and prospective studies that depression is a risk factor. The literature was also reviewed in relation to six hypotheses that might explain an association: (1) depression treatments are a risk factor for dementia, (2) dementia and depression share common risk factors, (3) depression is a prodrome of dementi..