Harvard Mental Health Letter

Dementia syndromes in the elderly

Alzheimer's disease is most common, but other diagnoses are possible.

The word dementia is derived from the Latin words de ("out of") and mens ("the mind"), but is now defined as a brain disorder that includes memory loss, deficits in cognition (thinking, planning, and organizing abilities), a decline in emotional control or motivation, and changes in social behavior (such as increased irritability, apathy, or problems interacting with other people).

Alzheimer's disease (also referred to as dementia of the Alzheimer's type), which affects roughly five million Americans and more than 35 million people around the world, is by far the most common dementia. About 50% to 56% of people with dementia are diagnosed with Alzheimer's, while another 13% to 17% carry that diagnosis plus a related disorder, vascular dementia. Here is a brief review of the most common dementia syndromes in the elderly.

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