Guide 3 of 5 · Support
What is dementia?
The main points
- Dementia is caused by diseases that damage the brain.
- It affects memory, thinking, talking and doing everyday tasks.
- It usually gets worse over time.
- It is not a normal part of getting old, and it is nobody’s fault.
What happens in dementia
Dementia is caused by diseases that slowly damage the brain. The brain controls how we remember, think, speak, move and feel. As the damage spreads, these things become harder and daily life needs more help. Because dementia is different for every person, care should fit the person.
The main types of dementia
Dementia is a word for a group of symptoms, not one single disease. The World Health Organization describes several diseases that can cause it. Knowing the type helps health workers choose the right care and treatment. The most common types are:
- Alzheimer’s disease — the most common type, behind 60–70% of cases. Memory problems are often the first sign.
- Vascular dementia — caused by problems with blood flow to the brain, for example after a stroke.
- Dementia with Lewy bodies — caused by abnormal deposits of protein inside nerve cells. It can cause changes in movement, sleep, and seeing things that are not there.
- Frontotemporal dementia — a group of diseases that damage the front of the brain. It often changes personality, behaviour or language first, and can start at a younger age.
- Mixed dementia — the types often overlap, and many people have more than one.
Other causes
Dementia can also have other causes. The World Health Organization lists several of them. Some of these can be prevented or treated early, which is another reason to get checked. They include:
- a stroke
- some infections, such as HIV
- harmful use of alcohol
- repeated injuries to the head
- poor nutrition
Source: World Health Organization, dementia fact sheet.
Who gets dementia?
Dementia is most common in people over 65. Younger people can get it too, which is called young-onset dementia. Many people with dementia also live with other health conditions, such as high blood pressure or diabetes. Looking after these conditions well is an important part of dementia care.
Can we lower the risk?
Nobody can promise to prevent dementia. Research shows that looking after the body and mind can lower the risk. This is because many things that harm the heart and blood vessels also harm the brain. These steps can help:
- Keep your body active.
- Do not smoke, and drink little or no alcohol.
- Eat a healthy diet and keep a healthy weight.
- Keep blood pressure, blood sugar and cholesterol under control.
- Spend time with other people, and keep your mind busy.
- Get help for hearing loss.
This guide gives general information about dementia. It is not medical advice for any one person. A doctor, nurse or health worker who knows the person can give advice that fits them. Please speak to them about any worries.