Relationship of family and personal history to the occurrence of depression in persons with Alzheimer's disease.

The authors tested the associations of family history and personal history of depression with mood disorders among patients with Alzheimer's disease (AD; N=161). Considered individually, a positive family history and a positive personal history each conferred increased risk for depression in AD. Conjointly, neither family nor personal history accounted for a substantial amount of the variance in syndromal depression after the onset of AD. Most depressed AD patients in this sample did not have a positive family history or a previous episode of depression. Our understanding of the etiology and course of depression and dementia may be augmented with further neuropsychological and brain-imaging studies of the neuropathological substrates shared by these illnesses.