Alzheimer's Disease

What is Alzheimer's disease?

Alzheimer's disease is the most common type of dementia. Dementia is a progressive condition in which the brain functions start to fail slowly. It affects a person's memory, personality and ability to think clearly. Alzheimer's disease is more common in older people but it is not a normal part of the ageing process.

Who gets Alzheimer's disease?

Approximately 850,000 people in the UK are thought to be affected by dementia, two thirds of them women. Dementia is uncommon in people under the age of 60. Above this age the proportion of people with dementia doubles for every five-year age group, with around one in six of the over 80s thought to be affected. Alzheimer's disease is the most common type of dementia accounting for over 60% of cases of dementia in the elderly. 

Alzheimer's disease usually develops after the age of 65. It can run in the family, but the risk of inheriting it is thought to be low. In the UK, current estimates suggest that around 520,000 people are affected by Alzheimer's disease, including over 40,000 with early-onset Alzheimer's (developing before the age of 65).

What causes Alzheimer's disease?

The cause of Alzheimer's disease is not fully understood. Currently, it is thought that a combination of factors, including age, gender, genetic inheritance, diet and overall general health, are responsible.

As the disease progresses proteins build up in the brain to form structures known as plaques and tangles. This leads to a loss of connection between nerve cells and eventually to death of nerve cells and loss of brain tissue. In addition, researchers believe that problems in the way messages are passed in the brain are responsible for some of the symptoms of Alzheimer's disease. One theory is that the disease may be associated initially with reduced levels of acetylcholine (ACh) in certain areas of the brain. Acetylcholine is a neurotransmitter, a chemical which aids the passage of messages throughout the body's nervous system. Most of the drugs that are available for use in the management of the symptoms of Alzheimer's disease work on the basis of this theory. Another theory is that Alzheimer's disease may develop as a result of problems with another process in the brain known as glutamatergic neurotransmission.

What are the symptoms of Alzheimer's disease?

People with Alzheimer's disease suffer a gradual loss of memory and ability to think clearly. As time passes, some people have a change in personality. For example, a previously calm person may become more easily agitated or upset. Their speech may become less clear or the sufferer may find it difficult to express themselves clearly.

Gradually it may become increasingly difficult for the person to perform tasks in their home or at work or to take part in social activities. In the more advanced stages of Alzheimer's disease the person may be unaware of their surroundings and unable to recognise the people close to them. Alzheimer's disease worsens over time but many people remain independent for several years before symptoms become severe.

What tests are needed?

The doctor may ask some simple questions to test for any memory problems. It will be important to rule out conditions that can be confused with Alzheimer's disease, such as other types of dementia, depression, thyroid disorders, vitamin deficiencies and infection. Side effects of drugs should also be ruled out. Sometimes hospital tests, such as a brain scan, may be needed, but in many cases the diagnosis can be made by the GP.

How can Alzheimer's disease be managed?

People with Alzheimer's disease and their carers need a wide range of support to help them cope. In the early stages, people with the disease may benefit from learning simple techniques to help a failing memory, eg, writing down lists of tasks and reminders about looking after themselves. As Alzheimer's disease progresses, people will need more support and help. This may involve help with everyday activities such as washing, dressing and eating. Eventually, full-time care may be needed for people with the most severe symptoms.

There are some medicines which may help to manage the symptoms of mild to moderate Alzheimer's disease. As mentioned above, researchers believe that some of the symptoms of the disease may be associated initially with reduced levels of acetylcholine in the brain. These medicines belong to a class of drugs called the acetylcholinesterase inhibitors which prevent the breakdown of acetylcholine in the brain. Currently, there are three drugs in this class which are licensed in the UK for use in Alzheimer's dementia: donepezil (eg, Aricept®), galantamine (eg, Acumor XL®, Consion XL®, Galantex XL®, Gatalin®, Gazylan XL®, Lotprosin XL®, Luventa XL®, Reminyl®) and rivastigmine (eg, Alzest®, Erastig®, Exelon®, Prometax®, Voleze®). These drugs may help to relieve some of the early symptoms of mild to moderate Alzheimer's disease but will not cure it nor delay or stop its progression.

Memantine (eg, Ebixa®, Nemdatine®, Valios®) works in a different way to the acetylcholinesterase inhibitors and can be used to treat moderately severe to severe Alzheimer's dementia. This drug was developed on the basis of the glutamatergic neurotransmission theory (see above) and can be used in conjunction with an acetylcholinesterase inhibitor.

Treatment with any of these drugs will be initiated by a specialist in Alzheimer's disease. Dosage will be increased gradually over a period of one to eight weeks, depending on the drug. Treatment should be continued only if there is positive evidence of benefit.


  • Talk to your doctor about any symptoms at an early stage, so that a diagnosis can be made and treatment offered
  • Ask your doctor or health visitor about the help that is available from the surgery, the hospital and the social services department
  • Take regular exercise, get plenty of rest and eat a healthy diet
  • Drink alcohol in moderation only and try to stop smoking
  • Try to accept any offers of support. Talk about your concerns with friends and relatives or with your doctor or health visitor
  • As this is a long-term illness, start to make some realistic plans for the future, ie, financial planning and decisions about future care
  • Remember that carers also need some outside support and regular breaks

Useful addresses

Alzheimer's Society
Devon House
58 St Katharine's Way
London E1W 1LB
Tel: 0330 333 0804
Helpline: 0300 222 1122

Alzheimer Scotland - Action on Dementia
22 Drumsheugh Gardens
Edinburgh EH3 7RN
Tel: 0131 243 1453
Helpline: 0808 808 3000 (24 hours)

Alzheimer's Research UK
3 Riverside
Granta Park
Cambridge CB21 6AD
Tel: 0300 111 5555

Fact sheet provided by MIMS

Date last reviewed: December 2015

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