Alzheimer disease (AD) is the most frequent cause of dementia in developed Western countries. Over time, affected patients invariably develop cognitive and functional decline, and most develop early or later behavioral disturbances. Declining cognitive and functional abilities contribute to loss of independent living and feelings of denial, confusion, fear and guilt until, finally, the patient loses most abilities to think, move, speak, or perceive. As patients' dependency on assistance increases, the level of caregiver strain rises. The caregiver may develop feelings of anger, grief, loneliness and resentment, and the health and well-being of most caregivers are often affected. Approximately 3-4 million people currently have AD in the USA, at an annual cost of up to US$100 billion, and the disease is expected to reach epidemic proportions by 2020. To achieve a clinically relevant, long-term outcome, pharmacotherapy must have sustained favorable effects on cognitive, functional and behavioral symptoms of AD. Slowing the development of these features of the disease will mean a long-term improvement in quality of life for patients and caregivers. Postponing the emergence of behavioral symptoms would bring about direct beneficial effects on patients with AD and their families, help delay long-term care placement and lower costs.