What are the main types of dementia?

The four most common types are Alzheimer's disease, which is by far the most common, then vascular dementia, Lewy body dementia, and frontotemporal dementia. Each comes from different changes in the brain and can bring different early symptoms, and a person can have more than one at the same time.

Dementia is not one condition. Several different diseases can damage the brain and produce it, and knowing which one is involved helps you understand what to expect. These are the four most common, drawing on the National Institute on Aging and the Alzheimer's Society.

Alzheimer's disease

The most common by far. It involves a build-up of two proteins, amyloid and tau, that form plaques and tangles and disrupt how brain cells work. Because it usually affects memory regions first, early symptoms tend to be trouble remembering recent events and learning new information.

Vascular dementia

The second most common. It is caused by reduced blood flow to the brain, often after a stroke or a series of small strokes. Early signs lean toward problems with planning, concentration, and speed of thought, sometimes with short episodes of sudden confusion, rather than memory alone.

Lewy body dementia

Caused by tiny deposits of a protein called alpha-synuclein (Lewy bodies) in the brain. It has a distinctive mix: alertness that fluctuates through the day, visual hallucinations, sleep disturbance, and Parkinson-like movement changes such as stiffness or a shuffling walk.

Frontotemporal dementia

Less common and often younger in onset, frequently before 65. It affects the frontal and temporal lobes, so the early changes are usually to personality, behavior, and language rather than memory. A person may act out of character or struggle to find words while memory stays relatively intact at first.

They can overlap

These types are not always separate. Someone can have more than one at once (often Alzheimer's plus vascular changes), which is called mixed dementia. That is one reason a careful diagnosis matters. If you want to understand what any specific type looks like or how it progresses, ask the doctor to name it, and start from there.

This is general information, not medical advice. Every situation is different, so talk to a doctor about yours.