Alzheimer's disease is the most common type of dementia, affecting almost 500,000 people in the UK.

The term "dementia" describes a loss of mental ability associated with gradual death of brain cells.

The exact cause of Alzheimer's disease is unknown, although a number of things are thought to increase your risk of developing the condition. These include:

• increasing age
• a family history of the condition
• previous severe head injuries
• lifestyle factors and conditions associated with cardiovascular disease

Read more about the causes of Alzheimer's disease.

Signs and symptoms of Alzheimer's disease

Alzheimer's disease is a progressive condition, which means the symptoms develop gradually and become more severe over the course of several years.

The first sign of Alzheimer's disease is usually minor memory problems. For example, this could be forgetting about recent conversations or events, and forgetting the names of places and objects.

As the condition develops, memory problems become more severe and further symptoms can develop, such as:

• confusion and disorientation
• personality changes, such as becoming aggressive, demanding and suspicious of others
• hallucinations (seeing things that are not there) and delusions (believing things that are untrue)
• problems with language and speech
• problems moving around without assistance

Read more about the symptoms of Alzheimer's disease.

Who is affected?

Alzheimer's disease is most common in people over the age of 65, and affects slightly more women than men.

The risk of Alzheimer's disease and other types of dementia increases with age, affecting an estimated one in every six people over the age of 80.

However, around 1 in every 20 cases of Alzheimer's disease affects people between 40 and 65 years of age.

Getting a diagnosis

As the symptoms of Alzheimer's disease progress slowly, it can be difficult to recognise there is a problem. Many people feel that memory problems are simply a part of getting older.

However, an early diagnosis of Alzheimer's disease gives you the best chance to prepare and plan for the future, as well as receive any treatment that may help.

If you are worried about your memory or think you may have dementia, it's a good idea to see your GP. If you're worried about someone else, you should encourage them to make an appointment and perhaps suggest that you go along with them.

There is no single test that can be used to diagnose Alzheimer's disease. Your GP will ask questions about any problems you are experiencing and may do some tests to rule out other conditions.

If Alzheimer's disease is suspected, you may be referred to a specialist to confirm the diagnosis and draw up a treatment plan.

Read more about diagnosing Alzheimer's disease.

How Alzheimer's disease is treated

There is no cure for Alzheimer's disease, but medication is available that can help improve some of the symptoms and slow down the development of the condition in some people.

Various other types of support are also available to help people with Alzheimer's live as independently as possible, such as making changes to your home so it's easier to move around.

Psychological treatments such as cognitive stimulation may also be offered to help improve your memory, problem-solving skills and language ability.

Read more about treating Alzheimer's disease.

Outlook

On average, people with Alzheimer's disease live for around 8 to 10 years after they start to develop symptoms. However, this can vary considerably from person to person. Some people with the condition will live longer than this, but others will not.

Alzheimer's disease is not usually the actual cause of death, but it is often a contributing factor. For example, a leading cause of death in people with Alzheimer's disease is pneumonia (lung infection), which may go untreated because people with the condition often aren't able to recognise that they're ill, or may not be able to tell someone they are feeling unwell.

Can Alzheimer's disease be prevented?

As the exact cause of Alzheimer's disease is not clear, there is no known way to prevent the condition. However, there are some steps you can take that may help reduce your risk or delay the onset of dementia, such as:

• stopping smoking if you smoke and cutting down on alcohol
• eating a healthy, balanced diet
• having regular health tests as you get older
• staying physically fit and mentally active

Taking these steps also has other health benefits, such as lowering your risk of cardiovascular disease and improving your overall mental health.

Read more about preventing Alzheimer's disease.