Dementia is a neurological disorder characterized by poor memory, mental disorientation, and impaired judgment. Having dementia may affect a wide range of cognitive abilities including language comprehension, attention span, memory, reasoning skills, learning capability, and even personality traits. Dementia is not a specific disease; instead is a collection of symptoms that can have several possible causes. The leading cause of dementia is Alzheimer’s disease but there are many others including: strokes, Parkinson’s disease, head trauma, multiple sclerosis, and HIV/AIDS. Some types of dementia are reversible while others are treatable but cannot be cured.

Dementia is not a normal consequence of aging, although it does become much more common as people get older. While everyone experiences memory lapses or a mild slowing of cognitive abilities as they age, dementia is a pathological condition that impairs thinking to the point of disability. Researchers estimate that 4.5 million Americans have dementia caused by Alzheimer’s disease and many others have dementia due to other causes. Researchers estimate that as many as 30% to 50% of those aged 85 and older may have dementia.

Dementia can also be purely psychological in origin when caused by a mental disorder. This article focuses on the more common type of dementia that is sometimes called organic dementia because it has a biological origin instead of a psychological one.