Are Alzheimer's disease and dementia the same thing?

Dementia is a group of symptoms that affect mental tasks such as memory or reasoning, while Alzheimer's is a disease of the brain that affects memory and cognition, states Healthline. A person can have dementia without having Alzheimer's, though the disease is the most common cause of dementia.

Diseases such as Parkinson's and Huntington's can cause dementia, as can infections, vascular diseases, stroke, depression and chronic drug use, notes Healthline. Alzheimer's disease causes protein deposits on the brain, leading to a loss of connection between brain cells, which eventually die. The exact cause of Alzheimer's disease is not known, as of 2015. The risk of contracting Alzheimer's or dementia increases with age.