Alzheimer's disease is the most common form of dementia in the United States. It and related dementias affect at least 2 million, and possibly as many as 4 million, U.S. residents. Despite its prevalence, dementia often goes unrecognized or is misdiagnosed in its early stages. Many health care professionals, as well as patients and family members, mistakenly view the early symptoms of dementia as inevitable consequences of aging.

Some disorders that result in dementia are "reversible or potentially reversible," which means that they can be treated effectively to restore normal or nearly normal intellectual function. Among the most frequent reversible causes of dementia are depression, alcohol abuse, and drug toxicity. In elderly persons, drug use—particularly drug interactions caused by "polypharmacy" (simultaneous use of multiple drugs)—is a common cause of cognitive decline. Depression also is an underdiagnosed condition in this population.

The majority of dementias, including Alzheimer's disease, are considered nonreversible. Even for these conditions, correct diagnosis of the problem in its early stages can be beneficial. Correct recognition can prevent costly and inappropriate treatment resulting from misdiagnosis, and give patients and families time to prepare for the challenging financial, legal, and medical decisions that may lie ahead. In addition, many of the nonreversible dementias such as Alzheimer's disease include symptoms that can be treated effectively (for example, incontinence, wandering, depression).

According to the National Institute on Aging, an estimated $90 billion is spent annually for Alzheimer's disease alone, and the noneconomic toll is incalculable. Although State and local governments and the Federal Government bear some of the economic burden, largely through Medicare and Medicaid, a substantial proportion is borne by families that provide unpaid care. Changes caused by dementia may advance relentlessly over many years, creating not only deep emotional and psychological distress but practical problems related to caregiving that can overwhelm affected families.

Addressing the Problem
In 1992, the Agency for Health Care Policy and Research, a Federal Government agency within the Public Health Service, convened a panel of private-sector experts to develop a clinical practice guideline on screening for Alzheimer's disease and related dementias. This topic was selected because:

• Dementia in the adult population is a serious and growing medical, social, and economic problem.

• Alzheimer's disease and related dementias exact a massive toll in health care costs, disability, and lost productivity of both patients and family caregivers.

• Early symptoms of dementia are commonly overlooked, mistakenly attributed to normal aging, or misdiagnosed.

• Failure to diagnose early-stage dementia can result in needless and possibly harmful treatment.