What is dementia?
Dementia is an umbrella term for over 100 different types of illnesses and disease symptoms.
What is dementia?
Dementia is a progressive condition that affects the brain in a variety of ways. There are many kinds of dementia but the most common is Alzheimer’s disease.
Other kinds of dementia include vascular dementia, Lewy body dementia, frontotemporal dementias (including Pick’s disease) and alcohol-related dementias.
It is possible to have more than one type of dementia; for example Alzheimer’s disease and vascular dementia. What all these diseases have in common is that they damage and kill brain cells, so that the brain can’t work as well as it should.
Frequently asked questions
What causes dementia?
We do not yet know exactly what causes dementia, however researchers all over the world are working to find causes and develop treatments.
Alzheimer’s disease (the most common type of dementia) damages individual brain cells one by one, so that the brain can’t work as well as it used to. A protein called amyloid builds up in deposits, called plaques, and tiny filaments in the brain cell form tangles.
What age does dementia start?
Dementia can start at any age but is most common in people over the age of 65. When dementia affects people younger than 65 it is known as young or younger onset dementia. Around 1 in 20 people with dementia are younger than 65.
Is dementia more common in males or females?
Dementia is more common among women than men. Approximately 65% of people with dementia are women. The difference between men and women is even more pronounced in Alzheimer’s disease, the most common type of dementia, where women are twice as likely to develop Alzheimer’s disease.
How many people in Scotland live with dementia?
In Scotland, it is estimated that over 90,000 people have dementia, and this means many of us will know someone living with it.
Is dementia preventable?
It is not always clear why some people get dementia while others do not. It can depend on a combination of age, genetics, lifestyle and other health conditions.
While dementia can be hereditary, most cases are not inherited from a parent to a child and familial genes are rare.
A Lancet Commission study published in 2024 estimates that up to 45% of cases of dementia could be preventable. According to the report there are 14 modifiable risk factors (things we can do to reduce our risk) for dementia. These are:
- high blood pressure
- physical inactivity
- excess alcohol
- smoking
- diabetes
- hearing impairment
- high body weight
- social isolation
- quality of education
- air quality
- brain injury
- depression
- visual impairment
- high cholesterol
Evidence is increasingly showing that looking after your brain health can significantly reduce the risk of getting dementia, especially if these actions are taken in mid-life (aged 40–65) or earlier.
You can learn more about this by visiting Brain Health Scotland and taking their Brain Health Quiz.
More information
Types of dementia
Learn more about the different types of dementia.
Symptoms and diagnosis
Learn about dementia symptoms, diagnosis and treatment
Preventing dementia
Find out what steps you can take to prevent dementia
Living with dementia
Learn how you can live well with dementia
I am a carer
A dementia diagnosis will result in changes for the person living with dementia and the people who care for them.
Carer support
It’s important to look after yourself, as well as the person you are caring for. Find out what support is available.
Brain Health & Dementia Resource Centres
Alzheimer Scotland’s Brain Health & Dementia Resource Centres offer friendly, accessible environments for everyone to enjoy. Our Centres are designed to be dementia friendly and create a sense of homeliness which we know is important in helping everyone to feel at ease. Each Centre is also a base for our wide range of local groups and activities.