Assessment and treatment of behavior problems in patients with Alzheimer disease and related disorders is a seriously neglected area of study. Despite the fact that such problems are integral to the disorder, little is known about effective management. This article summarizes the current thinking on five areas of prime importance to patients, care providers, and health care professionals: agitation, assault/aggression, screaming, wandering, and depression/apathy/withdrawal. Methodological guidelines for studying these disorders are provided. Emphasis is on recognizing that behavior problems are important areas of study in their own right as well as in conjunction with studies of cognition.