Past, present, and future directions for Alzheimer research.

To understand the current thinking and future research directions in Alzheimer disease (AD), it is essential to examine the breadth of research into AD. AD was identified as a distinct disease process early in this century and research into its etiology and treatment has a short, but active, history. This paper emphasizes past, present, and future biomedical research for the goal of stimulating research to solve some of the unanswered questions to ultimately help the victims of Alzheimer disease. The "hot" topics today for biomedical researchers include early diagnosis, presymptomatic markers, the role of presenilins, amyloid, protein precursor processing, and continued exploration for genetic and environmental risk factors.