What is the difference between Alzheimer's and dementia?

Alzheimer's disease is the most common kind of dementia. Dementia is not itself a disease; it's a set of symptoms that affect daily functioning (such as memory loss and changes in abstract reasoning and attention) caused by deterioration in the brain. Alzheimer's disease is the most common cause of dementia.

Sometimes the two terms are used interchangeably, often by those who find "Alzheimer's" to be a stigmatizing word. But technically they are not the same thing. Dementia is the broader, umbrella term; there are many different causes of dementia (disorders that feature dementia): vascular dementia; Parkinson's Disease dementia; Lewy Body Dementia; frontotemporal dementia. Alzheimer's is just one type of dementia. Dementia can also feature in other brain disorders such as Huntington's Disease and AIDS.

It's common for behavior to vary with Alzheimer's, with the person having "good" periods and "bad" ones. Stress or frustration can trigger intensified symptoms of aggression or withdrawal, for example. Or being in an unfamiliar situation might exaacerbate memory loss.

As far as driving with dementia, physicians strongly recommend against it. Getting lost -- even in familiar terrain -- is one surprisingly common risk. Another is the risk of accidents. With Alzheimer's, judgment and concentration are also affected. Someone driving with dementia is putting both himself and everyone else on the road at risk.