Dementia is a general word used to describe a set of symptoms. These symptoms often include:

  • loss of memory
  • mood changes
  • problems with communicating
  • difficulty completing day-to-day tasks
  • problems with reasoning

Dementia is progressive. This means that the symptoms will gradually get worse. The speed at which this happens usually depends on the person and what type of dementia they have.

There are many different types of dementia. They are often called by the same name as the condition that caused the dementia in the first place.

Dementia mainly affects people over the age of 65, and the risk increases with age. It can affect younger people as well. There is evidence that, in a few rare cases, the diseases that cause dementia can be inherited. Some people with a particular genetic make-up are more likely to develop dementia.

Everyone will experience dementia in a different way. It may be that your family and friends are more concerned about your symptoms than you are.

Symptoms of dementia

These are some things that you, your carer or loved ones might notice.

Loss of memory

It is usually your short-term memory that is affected. For example, you may forget what happened earlier in the day, or you may not be able to recall what you have been talking about. You may repeat things or forget the way home from the shops. Your long-term memory is not usually affected.

Mood changes

You may feel withdrawn, sad, frightened, or angry about what is happening to you.

Problems with communicating

It may be hard to find the right words for things. You may find yourself having to describe what an item does instead of being able to name it.

Daily living

You may find it difficult to maintain your daily routine and activities independently. Patience, prompting and support from carers and loved ones can help you to stay independent. These can have a big impact on how capable and confident you feel. 

Causes of dementia

There are several diseases and conditions that cause dementia, including the following.

Alzheimer’s disease

This is the most common cause of dementia. It gradually changes the chemistry and structure of your brain and causes brain cells to die. Problems with short-term memory are usually the first obvious sign.

Vascular dementia

This is caused by your brain not getting enough blood and oxygen. Without enough oxygen, brain cells die and cause vascular dementia. This can happen after a stroke or because the arteries (blood vessels) supplying oxygen to your brain are damaged. You can get the symptoms suddenly after a stroke, or over time (after a series of small strokes).

Dementia with Lewy bodies (DLB)

This type of dementia gets its name from tiny abnormal structures, called Lewy bodies, which build up inside the nerve cells in the brain. Lewy bodies cause brain tissue to break down and prevent the brain from working properly.

The symptoms can include:

  • confusion and hallucinations (seeing or hearing things that are not really there)
  • finding it hard to plan, reason and solve problems
  • memory problems in some cases

This type of dementia shares some symptoms with Parkinson's disease. It may mean that you are not able to have certain types of medicines.

Fronto-temporal dementia (including Pick's disease)

This type of dementia is usually caused by damage to the front part of your brain. It is more likely than other types of dementia to affect people at a younger age. The most obvious signs are changes in your personality and behaviour.

Diagnosing dementia

It is very important to get a proper diagnosis. We need to be sure that your symptoms are caused by dementia rather than another illness like depression or delirium (sudden confusion). These conditions can have similar symptoms.

You can read our information about delirium

A diagnosis can help you, your carer and your loved ones to prepare and plan for the future. Once you have a diagnosis, it may also be possible to prescribe you medicine for Alzheimer's disease.

Dementia can be diagnosed by your GP or by a specialist doctor. The specialist might be a geriatrician (caring for older people), psychiatrist (mental health), or a neurologist (diseases of the nervous system).

Your doctor might ask you to do a number of tests to check your basic thinking processes and your ability to do daily tasks. They may book more tests for you, such as blood tests, and a brain scan. They may also do a more in-depth check of your memory, ability to concentrate and thinking skills.

Treatment for dementia

Most types of dementia cannot be cured. However, there is a lot of research in to developing medicines, vaccines and other treatments.

There are several medicines that can temporarily improve the symptoms for some types of dementia. These medicines include the following 3 cholinesterase inhibitors:

  • donepezil
  • galantamine
  • rivastigmine

There is another medicine, called memantine (a glutamate receptor antagonist), which can be used. This is in a different class of drug to the cholinesterase inhibitors.

You can read more about these medicines on the Alzheimer's Society website.

If you need to come into hospital

Hospital can be confusing and frightening when you have dementia, and it may make you more confused than usual. You might find the ward loud and unfamiliar, and you may not understand why you are there.

If you have dementia and need to stay in hospital, you may be admitted to a general or a specialist hospital ward. Your stay with us may be as part of a planned (elective) procedure, such as a cataract operation, or after an accident, such as a fall.

It is important that all staff are aware that you have dementia. We ask your carers to give us as much information about you and your condition as they can. We can then carefully plan the care that you need.

Your named nurse should explain to other members of staff how your dementia can affect your behaviour and how you communicate. They should also tell staff if you prefer to be called by your first name, title or a nickname.

The Alzheimer's Society produces a booklet called This is Me, which can be used to write this information down. When it is filled in, it tells us more about who you are. It gives us details about your needs, interests, and what you like and dislike.

If you have memory problems and need more checks, you might be referred to a memory clinic after you have left hospital. This could be a clinic at Guy’s or St Thomas’ Hospitals or your local memory clinic.

Various health professionals work in memory clinics. These include:

  • doctors
  • nurses
  • physiotherapists (specialists who help with problems that affect your movement)
  • occupational therapists (specialists who help you with everyday activities)

Carers: looking after yourself

When you are caring for someone with dementia, it can be easy to ignore your own needs and forget that you matter too.

If you are caring for someone with dementia, be prepared for the fact that you will need support at some point. You might need different types of help and support. This could include:

  • practical care to give you breaks from being a carer
  • having someone to talk to about your feelings and concerns

It is a good idea to think in advance about what help you might need and where you can get it from. You will then know what support is available when you need it. 

Be clear about what support you need, especially when you ask for help in the form of services, and be assertive and persistent. Make it clear that you cannot continue with your caring role unless you receive the support that you need for yourself.

Useful information

The Alzheimer’s Society provides help, information and publications on living with dementia. Helpline phone: 0333 150 3456 

Dementia UK is a specialist dementia nursing charity. Their nurses, known as Admiral Nurses, provide free, life-changing support and advice to anyone affected by dementia. Helpline phone: 0800 888 6678

NHS.uk has lots of information and guidance about dementia.

Carers UK provides information, advice and support for all carers of family members or friends.

Resource number 3778/VER3
Date published: January 2024
Review date: January 2027

Contact us

If you have any questions or concerns about dementia, speak to a nurse or doctor. If the person with dementia is not in hospital, speak to their GP or community nurses.

You can also contact the delirium and dementia team.

Phone: 020 7188 7188 extension 53293. Monday to Friday, 9am to 5pm.

Out of hours, please call 020 7188 7188 and ask for the site nurse practitioner on duty.

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

Is this health information page useful?