Epidemiology and pathophysiology of Alzheimer's disease.

Researchers in Alzheimer's disease (AD) have made remarkable strides in the past 2 decades in characterizing the disorder, understanding its pathophysiology, and developing models for assessing treatment. With these successes and the promise of others to come, researchers and policy makers alike are keeping a nervous eye on the "demographic clock," which predicts that with the aging of the US population (and indeed the world), a massive increase in the number of AD cases and related dementias will emerge, flooding our medical care system and overwhelming our ability to care for these patients and their caregivers. This article explores some of the data underlying the explosion of AD and discusses the clinical disorder, its manifestations, and our advances in understanding the underlying pathobiology. Our growing knowledge of AD pathophysiology will lead us to the development of more effective medications to slow the progression or even prevent the emergence of this dreaded disorder.