Association Between Family History of Affective Disorder and the Depressive Syndrome of Alzheimer’s Disease

41 index patients with probable Alzheimer’s disease (AD) & a 1st episode of major depression & 71 nondepressed AD patients, had 2 1st-degree relatives interviewed by a rater blind to presence or absence of depression in the proband. The lifetime risk for major depression was significantly greater in 1st-degree relatives of index patients, suggesting that depression in AD is genetically related to primary affective disorder. AD may be useful for studying aspects of depressive pathophysiology.