Changes in dementia risk along with onset age of depression: a longitudinal cohort study of elderly depressed patients

The onset of depression after the age of 75 years was strongly associated with an increased risk of AD and a shorter time to dementia onset. Individuals with depression onset after age 75 appear more closely linked to vascular comorbidities, while those with depression onset before age 55 are characterized by severe and recurrent depressive episodes. The mechanisms underlying AD in individuals with depression may differ from those in individuals without prior depression.