What is dementia?
Your brain is amazing. It works hard to store memories. It helps us to make sense of the world. It controls everything we think, feel, say and do. Our brains make us who we are.
Hello! I’m Doctor Brain, your guide to the amazing universe hidden inside our heads.
We’re about to find out more about our brains and memories as well as what can happen when someone has an illness called dementia.
What does my brain do?
Your brain is like a complex jigsaw puzzle, filled with tiny pieces that fit together to create thoughts, feelings, and memories – everything that makes you you.
What is dementia?
Like other parts of the body, brains can sometimes get poorly. There are illnesses that stop a person’s brain from working properly. So, their brain starts to have problems doing all the jobs it has to do.
Doctors use the word dementia to describe an illness that causes these problems.
There are different diseases that cause dementia. Click on the tabs below to find out about them.
Alzheimer's is the most common illness that causes dementia. When people have Alzheimer's, it can make them forget things more often.
Vascular dementia can make people slower at thinking, and make it harder to decide what's right or wrong.
Dementia with Lewy bodies can cause hallucinations, which is seeing things that aren’t really there. People can also have big differences between their good days and bad days. On bad days, they may be much more confused and sleepy.
Frontotemporal dementia can cause different problems, like someone becoming being naughty or rude. Some people with frontotemporal dementia can’t speak very well or forget what words to use.
Who gets dementia?
In most cases, doctors don’t know why some people get the illnesses that cause dementia, but other people don’t. They are working hard to find out more about dementia.
When somebody you know is very ill, it can make you worry that you (or someone else in your family) might become ill too.
Having someone in your family with one of these illnesses does not mean that you will definitely get dementia when you are older too.
If you’re worried about dementia, you can ask a grown-up to help you find the answers to your questions.
Here are some facts we do know:
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You can't 'catch' dementia like a cold. Dementia doesn't spread from person to person.
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We can't guess who will get dementia when they get older.
But looking after our brains by eating a healthy, balanced diet, learning new things and being active can mean we're less likely to get dementia later on.
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Not all old people get dementia.
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Most people who have dementia become ill when they are in their 70s, 80s or 90s. But younger people can get it too.
What happens to someone with dementia?
When you were very young, you didn’t know how to walk, talk, play, eat or go to the toilet.
Today, all of this is stored in your brain.
When a person has dementia, their brain starts to forget the things they have learned.
At first people might forget words or names. They might forget what they’ve just said, or where they put something.
She lost her speech, she couldn’t talk to any of us anymore, it was like we could see her trying to say it but she couldn’t get her words out.
As dementia affects more of their brain, a person will start to forget more things. They might not know what objects are or what they’re used for. Things that used to be easy become very hard.
Some things that people with dementia might have trouble with include:
- Remembering things, like names or special dates.
- Talking and understanding things.
- Finding their way around, even if they are somewhere that they have been before.
She is always confused. She moves lots of objects to random places and sometimes she finds ways to leave the house by herself and manages to go very far.
This can make them feel scared or upset. They might not enjoy the same things that they used to.
She doesn't remember anyone apart from my grandad and she calls him dad.
He gets cross easily. We have to do what he wants.
My grandfather gets cross easily. We have to do what he wants.
The brain is like a jigsaw. As the disease progresses the jigsaw breaks up and pieces can be lost forever.
Can a person with dementia get better?
Doctors, nurses and carers cannot cure the illnesses that cause dementia, but they can help to make life easier for someone with dementia.
Scientists are working hard to find out more about dementia.
By understanding the illnesses that cause it, they are closer than ever to finding ways to prevent, treat and even cure dementia.
Remember, even though we can’t make everything better right now, there’s lots of amazing people helping those with dementia have the best possible life.
What can I do to help someone with dementia?
The best way you can help someone with dementia is to give them some of your time.
By spending time with them, you can help to make them feel loved and involved. Just being there can help.
- Small things like holding hands, sharing a hug or sitting together can feel special for everyone.
- Try asking questions about things they used to do, like sports teams they used to support or hobbies they used to enjoy.
At first I thought I’d never know my grandma again but since she got dementia I’ve learned to enjoy every small moment and really appreciate the time that we spend together.
You can visit our 'What works for us' page to read ideas from young people who have a grandparent or parent with dementia.
There are more tips on this page. You can also ask your family or somebody you trust for help.
How can I cope with my feelings?
It’s normal to feel many different emotions when somebody in your family has dementia but some can be very difficult to cope with. Here are some things you can do to help:
1. Talk about it
Don’t try to hide your feelings. Talk to someone you trust. This could be a parent, friend or teacher.
Be around people that understand. Being able to talk to people about it helps.
2. Be yourself
Being you is super important! It’s normal to feel sad that somebody has dementia. But it’s also okay to feel happy, to laugh, and to think about the other things that are happening in your life. Don’t feel bad about being yourself or having fun.
3. Ask questions
If you come across something that makes you feel scared, sad or just curious, ask someone about it.
How can I look after my brain?
There are things that we can all do to help look after our brains. This can help us to feel happier and healthier.
Click on each of the golden rules for looking after your brain below to find out more.
One of the most important things to do is look after your heart.
Our heart pumps blood around our bodies, making sure that our brain gets what it needs to work properly.
You can look after your heart by making sure that you do lots of exercise.
This could be playing sports with your friends or going for a walk with your dog.
Eating a healthy diet with lots of fruits and vegetables is really important too.
Playing games, doing puzzles and reading books are really good ways to get your brain working hard.
We have some games and activities here that you may enjoy.
Spending lots of time with our family and friends makes us feel happy and helps to look after our brains too.
Other things you can do to look after your brain
- Make sure you wear a helmet when riding your bike or scooter
- Don’t go to bed too late and get a good nights sleep
This information was updated in November 2025 and is due for review in November 2027. Please contact us if you would like a version with references.