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Dementia causes the (usually gradual) loss of mental abilities such as thinking, remembering and reasoning.
Brought to you by NHS Choices



Dementia is not a disease, but a group of symptoms that may accompany some diseases or conditions affecting the brain. The most common symptoms include loss of memory, confusion, and changes in personality, mood and behaviour.

Dementia usually affects older people and becomes more common with age. About one in 20 people over the age of 65 will develop some degree of dementia. This figure increases to about one in six people over the age of 85. Dementia can develop in younger people, but is less common, affecting about one in 1,400 of those under 65.

Although most of the people who develop dementia are over the age of 60, it’s important to remember that dementia is not a normal part of growing old.

Types of dementia

Alzheimer’s disease is the most common form of dementia, affecting around 400,000 people in the UK. ‘Plaques’ and ‘tangles’ develop in the structure of the brain, leading to the death of brain cells. Go to NHS Choices Alzheimer’s disease page for more information

Vascular dementia is the second most common form of dementia. It is caused by problems in the supply of blood to the brain.

Fronto-temporal dementia is one of the rarer forms of dementia. It is caused by damage to the frontal lobe and/or the temporal parts of the brain. People under the age of 65 are more likely to be affected by it.


Symptoms of dementia

In most cases, the symptoms of dementia progress gradually, over a period of several years. The early signs, usually memory problems, are normally subtle and may not be immediately obvious.

The symptoms of dementia can vary greatly, but those with dementia often have one or more of the following:

  • Problems with memory. This may include forgetting the names of people they know well, or forgetting where they live. Normally, recent memories are affected first, with memories of events further in the past only affected once the dementia becomes more developed. As dementia progresses, memory loss may affect memories of recent events so completely that the person appears to be ‘living in the past’. They may even think of themselves as young and not recognise their true age.
  • Problems with speech and language. They may forget simple words, may use the wrong words without noticing, or their conversation may become simplified, repetitive or irrelevant.
  • Confusion. They may become confused in new surroundings or by new people, or about who or where they are. They may lose track of time so that they are unsure what day it is, or even whether it is morning or afternoon.
  • Changes in mood or behaviour. They may become irritable or aggressive. As dementia progresses they may lose their normal inhibitions and begin to say or do inappropriate or antisocial things; in some cases this can include inappropriate sexual behaviour. They may lose interest in the outside world or their own care, giving up interests and hobbies, paying little attention to their personal hygiene, or forgetting to wash or change their clothes.
  • Difficulty performing simple tasks. They may have difficulty doing everyday tasks such as cooking a meal. They may begin cooking and then wander away, forgetting what they were doing, or they may prepare a meal and then forget to serve it.
  • Problems learning new information, ideas or skills.

Some types of dementia can cause less common symptoms, including:

  • hallucinations,
  • obsessive or repetitive behaviour,
  • the belief that they have done or experienced things that never happened (confabulation),
  • disturbed sleep, or sleeping in the daytime and being awake at night,
  • depression,
  • physical deterioration, loss of appetite, loss of weight and increased vulnerability to infection, and
  • incontinence.

If dementia becomes severe, it can cause other symptoms, including:

  • difficulty with swallowing,
  • difficulty changing position or moving from place to place without assistance, and
  • complete loss of short-term and long-term memory.

Sometimes, those with dementia are unaware that they have any symptoms, especially symptoms that affect behaviour.

Many conditions (such as depression) have symptoms similar to dementia, so it is important not to assume that someone has dementia just because they have some of the symptoms above.


Causes of dementia

Dementia develops when cells in the parts of your brain involved with mental ability become damaged. Damage to these cells can be caused by:

  • diseases and infections that affect the brain, such as Alzheimer’s disease or meningitis,
  • pressure on the brain, for example from a brain tumour,
  • lack of blood and oxygen supply to the brain, for example due to stroke, and
  • head injury.

The most common type of dementia is that caused by Alzheimer’s disease, which is responsible for about 60% of all cases. The cause of Alzheimer’s disease is unknown, except for a very small percentage of cases that are inherited.

About 20% of all cases of dementia are vascular dementias, the name given to dementia caused by poor circulation of blood in the brain. There are a number of different types of vascular dementia, the most common being multi-infarct dementia, where the small blood vessels in the brain become narrowed or blocked. The cells in the brain supplied by these blood vessels become starved of the blood and oxygen they need, and become damaged or die. This is like having a series of small strokes in the brain.

The risk of developing vascular dementia is increased by the same things that increase the risk of stroke and heart disease. These include high blood pressure, diabetes, smoking, poor diet and excessive alcohol intake.

Other less common types of dementia include:

  • Lewy body dementia,
  • dementia caused by Picks disease,
  • dementia caused by Huntington’s disease,
  • dementia caused by Creutzfeld-Jakob disease (CJD),
  • dementia caused by the advanced stages of syphilis or HIV/AIDS,
  • dementia caused by hypothyroidism (under-activity of the thyroid gland),
  • dementia caused by build-up of fluid within the skull leading to pressure on the brain (hydrocephalus),
  • dementia caused by infections of the brain, such as meningitis or encephalitis,
  • dementia as part of a neurological (brain) illness, such as Parkinson’s disease or multiple sclerosis,
  • dementia caused by reaction to a medication, or to an interaction of two or more medications,
  • dementia caused by long-term alcohol misuse,
  • dementia caused by use of illegal drugs, and
  • dementia caused by lack of certain hormones or nutrients, especially B vitamins.


Diagnosing dementia

Dementia usually develops slowly, with mild early symptoms, so diagnosing dementia in its early stages can be difficult. It is normally diagnosed initially by the most common symptoms, such as memory loss. The diagnosis can be confirmed with a careful physical and mental examination and simple memory and mental ability tests that check things such as the ability to read, write or calculate.

However, as different types of dementia have similar symptoms, it can be more difficult to diagnose the precise type or cause. Blood tests, X-rays or a CT or MRI scan of the brain may be necessary to provide more information.

Further tests may be needed to make sure that the person does not have a condition that can produce symptoms similar to dementia, such as depression or a severe urine or chest infection.

As those with dementia are often unaware they have a problem, many people with dementia are brought to medical attention by a relative or friend.

The time it takes to make a diagnosis can vary. If scans and other investigations are required, it could be four to 12 weeks, depending on waiting lists. If the person is in the early stages of dementia, a six- to 12-month period of monitoring may be required before a diagnosis can be made.

I’ve heard about the MMSE. What is it exactly?
The Mini Mental State Examination (MMSE) is the most commonly used test for complaints of memory problems or when a diagnosis of dementia is being considered.

The MMSE is the test the NHS recommends for deciding whether a drug treatment for Alzheimer’s disease should be prescribed. NHS guidance recommends that you should score 10 points or more out of a maximum of 30 points to be considered for treatment with donepezil (Aricept), rivastigmine (Exelon) or galantamine (Reminyl).

The MMSE is a series of questions and tests, each of which scores points if answered correctly. If every answer is correct, a maximum score of 30 points is possible. People with mild Alzheimer’s disease generally score 21 to 26 points or less. It is important to remember that this is not a test for Alzheimer’s disease. There are many other reasons why you might score less than 26 points.

How quickly will my Alzheimer’s progress?

Although Alzheimer’s is considered to be a fatal disease, the actual cause of death is usually another illness (such as pneumonia). On average, people with Alzheimer’s die between seven and 10 years after first experiencing symptoms. However, the rate at which the disease progresses varies in different people, from three to 20 years.


Treating dementia

Most types of dementia cannot be cured. The exceptions are:

  • those dementias related to vitamin or hormone deficiency, which can be treated with supplements,
  • those related to head injury, hydrocephalus or tumour, which may be treatable with surgery,
  • those related to medication, which can be treated by altering the medication, and
  • those related to infections, where treating the infection will normally cure the dementia.

Medication for Alzheimer’s disease

Alzheimer’s disease cannot be cured. However, for some people in the early and middle stages of the disease, the medicines donepezil (Aricept), rivastigmine (Exelon) and galantamine (Reminyl) may help prevent some symptoms from becoming worse for a period of time. A new medicine called memantine (Ebixa) may have the same effect for some people who have moderate or severe Alzheimer’s disease.

How do they work?
Aricept, Exelon and Reminyl all work in a similar way and are known as acetylcholinesterase inhibitors.

Research has shown that there is not enough of a chemical called acetylcholine in the brains of people with Alzheimer’s disease. Acetylcholine is one of the chemicals that nerve cells use to communicate.

Aricept, Exelon and Reminyl prevent an enzyme from breaking down acetylcholine in the brain. Increased concentrations of acetylcholine lead to increased communication between nerve cells, which may in turn temporarily improve or stabilise the symptoms of Alzheimer’s disease.

Aricept, Exelon and Reminyl are only used in people with mild to moderate Alzheimer’s disease. They are not effective for everyone and may only temporarily improve memory or delay memory loss.

Revised guidance by the National Institute for Health and Clinical Excellence (NICE) recommends that:

  • Anticholinesterase drugs are given to people in the moderate stages of Alzheimer’s disease.
  • People with Lewy-body dementia may be offered an acetylocholinesterase inhibitor if they find that their non-cognitive symptoms are very distressing.

NICE has also recommended that Aricept, Exelon and Reminyl should be available on NHS prescription for anyone with a diagnosis of Alzheimer’s disease who could benefit from the drug treatment. See page on NICE guidance for more information

Ebixa can temporarily slow down the progression of symptoms in people in the middle and later stages of the disease. There is also a suggestion that Ebixa may slow down the disease process itself.

Medical researchers are currently investigating other medical treatments, including antioxidants, brain stem cell therapy and a vaccination to stop the build-up of plaques in the brain (a hallmark of Alzheimer’s disease).

What are the side effects?
Not everyone has the same side effects or has them for the same length of time, if they have them at all. The most frequent side effects of Aricept, Exelon and Reminyl include:

  • nausea and vomiting,
  • diarrhoea,
  • stomach cramps and headaches,
  • dizziness,
  • fatigue,
  • insomnia and
  • loss of appetite.

Side effects of Ebixa include hallucinations, confusion, dizziness, headaches and tiredness.

Importance of mental activity

It is thought that mental activity can help to slow the progress of some types of dementia, so you should encourage someone with dementia to stay mentally and physically active and ensure their environment is stimulating. Puzzles, games (particularly memory games), reading and simple mental arithmetic are good choices, but it’s important not to overwhelm them with too many demands, or unrealistic demands, as this may only frustrate them.

A technique called reality orientation may help some people with dementia. It uses repetition to help the memory and involves regularly reminding the person of information such as the time, date, where they are and important information for that day, such as a visit to see a friend. The information could be given verbally by a carer, or be written on a board in their home where they will see it regularly. The aim of reality orientation is to help people understand their situation by reminding them or telling them about what’s going on.

Care and support

Many of those with dementia in the early and intermediate stages are able to cope well in their own home, due to the familiar surroundings. Others may need more frequent supervision, full-time care in the home, or care in a residential or nursing home.

Support and care is the most important part of treatment for dementia. Many people with dementia are cared for in the community, often by a relative or friend. However, caring for a person with dementia can be very difficult. Support and advice for those caring for someone with dementia is available from the following sources:

  • district nurses, who can advise on day-to-day nursing care,
  • community psychiatric nurses, who can advise on caring for someone with a mental illness,
  • social services, who can help with care in the home, day-care centres, respite care and benefits,
  • voluntary organisations - in most areas of the UK there are organisations that provide support and advice for carers of people with dementia.

Practical tips

  • Keep a diary and write down things you want to remember.
  • Pin a weekly timetable to the wall.
  • Put your keys in an obvious place such as a large bowl by the door.
  • Have a daily newspaper delivered to remind you of the date and day.
  • Put labels on cupboards or drawers.
  • Place helpful telephone numbers by the phone.
  • Write reminders - e.g. put a note on the front door to take your keys.
  • Telephones allow you to programme people’s names and numbers.
  • Many watches have alarms that can act as reminders.
  • Install safety devices, such as gas detectors and smoke alarms.

Questions to ask your doctor

  • What are the potential benefits of taking these drugs?
  • How long will it be before I see a result?
  • How often do these drugs need to be taken?
  • If there are side effects should I stop taking it?
  • What happens if I stop taking them suddenly?
  • What other treatments might interact with these drugs?
  • Can I drink while taking the drug?
  • How might these drugs affect other medical conditions?
  • What changes in health should be reported immediately?
  • Why is one drug prescribed rather than another?
  • If one drug proves ineffective can I try another?


Preventing dementia

There is no known way to prevent Alzheimer’s disease, the most common cause of dementia. However, you can reduce the risk of vascular dementia by maintaining a healthy lifestyle, including:

  • quitting smoking (smoking has a harmful effect on the blood vessels in the brain),
  • eating a low-fat, balanced diet,
  • doing regular exercise,
  • drinking no more than the safe recommended limits of alcohol.

NICE guidelines

Information on dementia

It’s important to go to a reliable source for more information on dementia.

The National Institute for Health and Clinical Excellence (NICE) has produced a booklet about the support and treatment of people with dementia in the NHS and social care services in England and Wales.

NICE has also published healthcare guidelines on when the treatments donepezil, galantamine, rivastigmine and memantine should be used to treat people with Alzheimer’s disease in England and Wales.

Expert view

Dementia expert Clive Evers on the questions to ask

We asked Clive Evers, director of knowledge management for the Alzheimer’s Society, what he would want to know if he was diagnosed with dementia.

Can dementia be treated?
There are no treatments that can reverse the progress of dementia once it has developed. However, there are some drugs that may alleviate some of the symptoms of Alzheimer’s disease and some other types of dementia for a limited period of time, although they don’t work for everyone. If you’re on medication for another condition, talk to your GP about whether it’s essential. Some medication has side effects that can cause additional confusion. The same goes for over-the-counter drugs and complementary medicines.

What type of specialist help can I get?
If you haven’t already been referred, ask your doctor to refer you to a specialist such as an psychiatrist who has experience of treating the elderly, or another suitable consultant. They work within a multi-disciplinary team that consists of a psychologist, occupational therapist, community psychiatric nurse and speech and language therapist, who all have experience in dealing with the problems caused by dementia. There are also support services available, such as those provided by the voluntary and community sector, and it’s worth looking into them. Although you may not need them right away, you may need the support and advice they offer in the future.

Do I need to stop driving?
You don’t necessarily have to stop driving immediately, but you must inform your insurance company and tell the Driver and Vehicle Licensing Authority (DVLA) of your diagnosis. The DVLA will ask for medical reports and possibly a driving assessment in order to decide whether you can continue driving.

Will I feel unwell?
Dementia doesn’t mean you will feel ill, so you should see your GP if you feel unwell or if you have health concerns. It is a good idea for everyone, especially older people, to have regular sight, hearing and dental check-ups.

What should I tell my family?
If friends and family don’t already know about the diagnosis, try to tell them as soon as possible. Try to be calm. They may not believe you at first because they are so upset by the news. Talk about your own wishes for the future, but try not to ask people to make promises now that could be difficult to keep in the future. Sometimes it can help to talk to someone you trust outside the family.

Who will manage my finances when I am not able to?
You should try to make time to sort out your finances and legal affairs. However, the Alzheimer’s Society can provide a list of solicitors with experience of helping people with dementia.

Real stories

Stan and Denise’s story

Stan Lintern has had Alzheimer’s disease for 10 years. He is cared for by his wife Denise, who helped set up the Maidstone branch of the Alzheimer’s Society and runs the helpline. Last year, she was awarded an MBE for services to her local community. They have three children

“I was 49 when Stan was diagnosed. He’d been having problems with his memory for a bit and after taking early retirement, he was lacking in motivation. We thought it was due to him missing his work. His behaviour began to be a bit odd at times, so when I was seeing our GP, I mentioned it. The GP suggested that Stan go for an appointment. After about six months of extensive tests, Stan was diagnosed with Alzheimer’s.

“It was a devastating shock, but also good in a way because at least we knew what we were dealing with. It had been horrible not knowing what was causing his weird behaviour.

“For the first few years, we carried on with normal life. Stan was a Premier League table tennis player and he still enjoyed doing that. He continued to drive and we went on lots of holidays. He was a very meticulous man and liked everything to be ‘just so’. But, as the Alzheimer’s took over, he just decided he wasn’t going to do things any more. I think he thought that if he couldn’t do it the way he liked to do it he wasn’t going to bother anymore.

“Every time there has been a big change with Stan, I have to stop and take stock. Stan needs full-time care now. He’s in a wheelchair and needs to be fed. He doesn’t speak any more and I’m not sure that he understands what I’m saying. I have some outside help during the week, but mostly it’s down to me.

“We still go away. I have a hoist for getting him around indoors and a Transporter ‘truck’ with a hydraulic tail lift to go out in. We still like going to Holland to see my cousins and their families, and visiting various places in the UK. The only thing we don’t do is fly anywhere. I don’t feel a prisoner because I’ve made sure that I can be independent and that we can get away. Stan is always more awake and aware when we’re doing something different.”

Dawn’s story

‘I couldn’t have done it without support’

Life for Dawn and Dave Edmonds changed forever five years ago when he was diagnosed with Alzheimer’s

“I was 45 when Dave was diagnosed with Alzheimer’s disease. Now I feel like I’m living in an emotional desert. I haven’t had sex for six years and I’ve lost my best friend: my husband.

“We were on holiday when I first realised he was having problems with his memory. If we left the hotel separately, he couldn’t find his way back. He couldn’t write his signature on travellers’ cheques.

“No one could believe Dave had Alzheimer’s because he was so young and fit. But fortunately we were soon referred to a wonderful consultant. His help and the right medication had a huge positive effect on Dave.

“Dave is very intelligent but he needs a lot of support. His main problem is with short-term memory. He often gets lost in the house and won’t be sure which direction the kitchen is in.

“Support from carers’ groups such as Crossroads has been invaluable. I’ve worked with them to set up a support organisation for people like us.

“It’s important to get as much help as you can, and find specialists with an interest in your condition.”

Useful links

NHS Choices links

External links

This article was originally published by NHS Choices

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