Dementia is a general decline in a person's mental abilities that is severe enough to interfere with daily living and activities. It affects memory, problem solving, learning, and other mental functions.

A variety of conditions can cause dementia, including injuries to the brain from tumors, head injury, or stroke; diseases, such as Alzheimer's disease; or long-term alcohol dependence. People (especially older adults) who are depressed may seem to have dementia when they do not (pseudodementia).

People who have dementia often experience:

• Confusion and memory loss.
• Inability to complete everyday tasks.
• Loss of self-control leading to unexpected behavior, such as throwing things, yelling at other people, or being suspicious of others.
• Impaired judgment and reduced ability to make decisions and learn new things.
• An eventual loss of control over physical functions, such as urination.