About Alzheimer's disease

Alzheimer's disease is the most common type of dementia, affecting an estimated 850,000 people in the UK.

Dementia is a progressive neurological disease which affects multiple brain functions, including memory.

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:

It's becoming increasingly understood that it's very common to have both changes of Alzheimer's and vascular dementia together (mixed dementia).

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. It affects multiple brain functions.

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, disorientation and getting lost in familiar places
  • difficulty planning or making decisions
  • problems with speech and language
  • problems moving around without assistance or performing self-care tasks
  • personality changes, such as becoming aggressive, demanding and suspicious of others
  • hallucinations (seeing or hearing things that aren't there) and delusions (believing things that are untrue)
  • low mood or anxiety

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 1 in 14 people over the age of 65 and 1 in every 6 people over the age of 80.

However, around 1 in every 20 cases of Alzheimer's disease affects people aged 40 to 65.

Receiving a diagnosis

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

However, a timely diagnosis of Alzheimer's disease can give you the best chance to prepare and plan for the future, as well as receive any treatment or support that may help.

If you're 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's 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 memory service to:

  • discuss the process of making the diagnosis
  • organise testing 
  • create a treatment plan

Read more about diagnosing Alzheimer's disease

How Alzheimer's disease is treated

There's no cure for Alzheimer's disease, but medication is available that can help relieve some of the symptoms and slow down the progression 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 environment so it's easier to move around and remember daily tasks.

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

Read more about treating Alzheimer's disease


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 a life-limiting illness, although many people diagnosed with the condition will die from another cause.

As Alzheimer’s disease is a progressive neurological condition, it can cause problems with swallowing. This can lead to aspiration (food being inhaled into the lungs) which can cause frequent chest infections. It's also common for people with Alzheimer’s disease to eventually have difficulty eating and to have a reduced appetite. 

There's increasing awareness that people with Alzheimer’s disease need palliative care. This includes support for families, as well as the person with Alzheimer's.

Can Alzheimer's disease be prevented?

As the exact cause of Alzheimer's disease isn't clear, there's no known way to prevent the condition. However, there are things you can do that may reduce your risk or delay the onset of dementia, such as:

These measures have other health benefits, such as lowering your risk of cardiovascular disease and improving your overall mental health.

Read more about preventing Alzheimer's disease

Symptoms of Alzheimer's disease

The symptoms of Alzheimer's disease progress slowly over several years. Sometimes these symptoms are confused with other conditions and may initially be put down to old age.

The rate at which the symptoms progress is different for each individual and it's not possible to predict exactly how quickly it will get worse.

In some cases, infections, medications, strokes or delirium can be responsible for symptoms getting worse. Anyone with Alzheimer's disease whose symptoms are rapidly getting worse should be seen by a doctor, so these can be managed.

Stages of Alzheimer's disease

Generally, the symptoms of Alzheimer's disease are divided into three main stages.

Early symptoms

In the early stages, the main symptom of Alzheimer's disease is memory lapses. For example, someone with early Alzheimer's disease may:

  • forget about recent conversations or events, or misplace items
  • forget the names of places and objects, or have trouble thinking of the right word
  • repeat themselves regularly, such as asking the same question several times
  • show poor judgement or find it harder to make decisions
  • become less flexible and more hesitant to try new things

There are often signs of mood changes, such as increasing anxiety or agitation, or periods of confusion.

Middle-stage symptoms

As Alzheimer's disease develops, memory problems will get worse. Someone with the condition may find it increasingly difficult to remember the names of people they know and may struggle to recognise their family and friends.

Other symptoms may also develop, such as:

  • increasing confusion and disorientation – for example, getting lost, or wandering and not knowing what time of day it is
  • obsessive, repetitive or impulsive behaviour
  • delusions (believing things that are untrue) or feeling paranoid and suspicious about carers or family members
  • problems with speech or language (aphasia)
  • disturbed sleep
  • changes in mood, such as frequent mood swings, depression and feeling increasingly anxious, frustrated or agitated
  • difficulty performing spatial tasks, such as judging distances
  • hallucinations

By this stage, someone with Alzheimer's disease usually needs support to help them with their everyday living. For example, they may need help eating, washing, getting dressed and using the toilet.

Later symptoms

In the later stages of Alzheimer's disease, the symptoms become increasingly severe and distressing for the person with the condition, as well as their carers, friends and family.

Hallucinations and delusions may come and go over the course of the illness, but can get worse as the condition progresses. Sometimes people with Alzheimer's disease can be violent, demanding and suspicious of those around them.

A number of other symptoms may also develop as Alzheimer's disease progresses, such as:

In the severe stages of Alzheimer's disease, people may need full-time care and assistance with eating, moving and using the toilet.

Read more about how Alzheimer's disease is treated

Seeking medical advice

If you're 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.

Memory problems are not just caused by dementia – they can also be caused by depression, stress, medications or other health problems. Your GP can carry out some simple checks to try to find out what the cause may be, and they can refer you to a specialist for more tests, if necessary.

Read more about diagnosing Alzheimer's disease

Causes of Alzheimer's disease

Alzheimer's disease is caused by parts of the brain shrinking (atrophy), which affects the structure and function of particular brain areas.

It's not known exactly what causes this process to begin. However, in the brains of people with Alzheimer's disease, scientists have found amyloid plaques (abnormal deposits of protein), neurofibrillary tangles (containing tau) and imbalances in a chemical called acetylcholine.

It's also common to have a degree of vascular damage in the brain.

These reduce the effectiveness of healthy neurons (nerve cells that carry messages to and from the brain), gradually destroying them.

Over time, this damage spreads to several areas of the brain. The first areas affected are responsible for memories.

Increased risk

Although it's still unknown what triggers Alzheimer's disease, several factors are known to increase your risk of developing the condition.


Age is the single most significant factor in the development of Alzheimer's disease. The likelihood of developing the condition doubles every five years after you reach 65 years of age.

However, it's not just older people who are at risk of developing Alzheimer's disease. Around 1 in 20 people with the condition are under 65. This is called early onset Alzheimer's disease and it can affect people from around the age of 40.

Family history

The genes you inherit from your parents can contribute to your risk of developing Alzheimer's disease, although the actual increase in risk is small if you have a close family member with the condition.

However, in a few families, Alzheimer's disease is caused by the inheritance of a single gene, and the risks of the condition being passed on are much higher.

If several of your family members have developed dementia over the generations, it may be appropriate to seek genetic counselling for information and advice about your chances of developing Alzheimer's disease when you are older.

The Alzheimer's Society website has more information about the genetics of dementia.

Down's syndrome

People with Down's syndrome are at a higher risk of developing Alzheimer's disease.

This is because the genetic fault that causes Down's syndrome can also cause amyloid plaques to build up in the brain over time, which can lead to Alzheimer's disease in some people.

Head injuries

People who have had a severe head injury have been found to be at higher risk of developing Alzheimer's disease.

Cardiovascular disease

Research shows that several lifestyle factors and conditions associated with cardiovascular disease can increase the risk of Alzheimer's disease.

These include:

You can help reduce your risk by:

  • stopping smoking
  • eating a healthy, balanced diet
  • leading an active life, both physically and mentally
  • losing weight if you need to
  • drinking less alcohol
  • having regular health checks as you get older

Read more about reducing your risk of Alzheimer's disease

Diagnosing Alzheimer's disease

It's best to see your GP if you're worried about your memory or think you may have dementia.

If you're worried about someone else, encourage them to make an appointment and perhaps suggest going with them. It's often very helpful having a friend or family member there.

A timely diagnosis gives you the best chance to adjust, prepare and plan for the future, as well as accessing treatments and support that may help.

Seeing your GP

Memory problems aren't just caused by dementia – they can also be caused by:

  • depression or anxiety
  • stress
  • medications
  • alcohol or drugs
  • other health problems – such as hormonal disturbances or nutritional deficiencies

Your GP can carry out some simple checks to try to find out what the cause may be. They can then refer you to a specialist for assessment, if necessary.

Your GP will ask about your concerns and what you or your family have noticed. They'll also check other aspects of your health, and carry out a physical examination. They may also organise some blood tests and ask about any medication you're taking to rule out other possible causes of your symptoms.

You'll usually be asked some questions and carry out some memory, thinking, and pen and paper tasks to check how different areas of your brain are functioning. This can help your GP decide if you need to be referred to a specialist for more assessments.

Referral to a specialist

Your GP may refer you to a specialist memory assessment service to help with your diagnosis. Memory clinics are staffed by professionals from multiple disciplines who are experts in diagnosing, caring for and advising people with dementia and their families.

Memory clinic staff can include the following, depending on your local area:

  • a nurse – usually a trained mental health nurse who specialises in diagnosing and caring for people with dementia
  • a psychologist – a healthcare professional who specialises in the assessment and treatment of mental health conditions
  • a psychiatrist – a qualified medical doctor who has training in treating mental health conditions
  • a neurologist – a specialist in treating conditions that affect the nervous system (the brain and spinal cord)
  • a geriatrician – a physician with specialist training in the care of older people
  • a social worker – a trained member of staff able to advise and assist with accessing social services within the local area
  • an occupational therapist – a member of staff with specialist skills in assessing and supporting people with dementia and their families with adjusting to disabilities

There's no simple and reliable test for diagnosing Alzheimer's disease, but the staff will listen to the concerns of both you and your family about your memory or thinking. They will assess your skills and arrange more tests to rule out other conditions.

Assessing your mental abilities 

A specialist will usually assess your mental abilities using a special series of questions.

One widely used test is the mini mental state examination (MMSE). This involves being asked to carry out activities such as memorising a short list of objects correctly and identifying the current day of the week, month and year. Different memory clinics may also use other, longer tests. 

The MMSE isn't used to diagnose Alzheimer's disease, but it's useful to initially assess areas of difficulty that a person with the condition may have. This helps specialists to make decisions about treatment and whether more tests are necessary.


To rule out other possible causes of your symptoms and look for possible signs of damage caused by Alzheimer's disease, your specialist may recommend having a brain scan. This could be a:

Some specialist centres offer scans which look at brain function and particular protein deposits. However, at the moment, these are mostly experimental and only used if the diagnosis is unclear. 

After diagnosis

It may take several appointments and tests over months, or even years, before a diagnosis of Alzheimer's disease can be confirmed.

For some people, a diagnosis of Alzheimer's disease is a huge shock, especially as it's not unusual for people with dementia to have less awareness of their difficulties.

For others, the diagnosis can be very important in helping them and their families to make sense of symptoms they've been concerned about for a long time.

If you've just been given a diagnosis of dementia, you may be feeling numb, scared and unable to take everything in. It may be helpful to have the diagnosis explained again to help make sense of the idea over time. It might help to talk things through with family and friends.

It takes time to adapt to a diagnosis of dementia, for both you and your family. Some people find it helpful to seek information and plan for the future, but others may need a longer period to process the news.

However, as dementia is a progressive illness, the weeks to months after a diagnosis is often a good time to think about legal, financial and healthcare matters for the future.

Read more about what to do if you've just been diagnosed with dementia

Treating Alzheimer's disease

There's currently no cure for Alzheimer's disease, although medication is available that can temporarily reduce some symptoms or slow down the progression of the condition in some people.

Support is also available to help someone with the condition cope with everyday life.

Care plan

If you're diagnosed with Alzheimer's disease, it's helpful if your health and social care needs are assessed and plans made for the future.

A care plan is a way of ensuring you receive the right treatment for your needs. It involves identifying areas where you may need some assistance, such as:

  • what support you or your carer need for you to remain as independent as possible
  • whether there are any changes that need to be made to your home to make it easier to live in
  • whether you need any financial assistance

Healthcare professionals (such as your GP or psychiatrist) and social care services (which is normally your local council working with the NHS), will usually both be involved in helping draw up and carry out care plans.


A number of medications may be prescribed for Alzheimer's disease to help temporarily improve some symptoms and slow down the progression of the condition.

Donepezil, galantamine and rivastigmine (known as AChE inhibitors) can be prescribed for people with early to mid-stage Alzheimer's disease. Memantine may be prescribed for people with mid-stage disease who cannot take AChE inhibitors, or for those with late-stage disease.

There's no difference in how well each of the three different AChE inhibitors work, although some people respond better to certain types or have fewer side effects.

All of these medications can only be prescribed by specialists such as psychiatrists, neurologists and geriatricians. They may be prescribed by your GP on the advice of a specialist.

If you're caring for someone with Alzheimer's disease, your views should be taken into account when prescribing medication, as well as at regular assessments. These assessments take place to ensure the medication is having a worthwhile effect and to identify and monitor side effects.

Read guidance from the National Institute for Health and Care Excellence (NICE) on donepezil, galantamine, rivastigmine and memantine for the treatment of Alzheimer's disease.

Side effects

Donepezil, galantamine and rivastigmine can cause side effects such as:

  • feeling and being sick
  • dizziness
  • diarrhoea 
  • headache 
  • agitation
  • insomnia
  • muscle cramps
  • more rarely, slowing of the heartbeat – which can cause issues if you already have problems with your heart rhythm.

These side effects are more likely to occur at the beginning of therapy or when the dose is increased. Your doctor should review your medical history and your other medications to check the suitability and risk of interactions.

Common side effects of memantine include:

  • dizziness
  • headaches
  • high blood pressure
  • tiredness
  • constipation
  • shortness of breath
  • more rarely, problems with walking or increased confusion
  • very rarely, seizures

For more information about the possible side effects of your specific medication, refer to the patient information leaflet that comes with it or speak to your doctor.

Supportive measures and treatments

In addition to medication, treatment for Alzheimer's disease involves a wide range of other measures and treatments to help people with dementia live as independently as possible.

For example, an occupational therapist can identify problems or unsafe areas in your everyday life and help you to develop strategies or use alternative tools to manage these. They may suggest:

  • ways of prompting and reminding yourself of important tasks – such as using diaries or calendars
  • assistive technology – devices or systems to help maintain the independence and safety of people living with dementia
  • adding grab bars and handrails to your home to help you move around safely
  • other professionals visiting you at home and assisting with daily tasks to maintain your independence in the community

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

Medication, other psychological therapies, such as cognitive behavioural therapy (CBT), music and art therapy, reminiscence and relaxation therapies may also be offered. These may help with managing depression, anxiety, agitation, hallucinations, delusions and challenging behaviour that can occur with Alzheimer's disease.

Read more about how dementia is treated

Practical tips for people with Alzheimer's

If you have Alzheimer's disease, you may find it useful to:

  • 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 in a large bowl in your living room
  • have a daily newspaper delivered to remind you of the day and date
  • put labels on cupboards and drawers
  • keep useful telephone numbers by the phone
  • write yourself reminders – for example, put a note on the front door to remind you to take your keys with you if you go out
  • programme people's names and numbers into your telephone
  • set the alarm on your watch to act as a reminder
  • install safety devices such as gas detectors and smoke alarms throughout your home

It may also be helpful to get in touch with a local or national Alzheimer's or dementia support group, such as the Alzheimer's Society, for more information and advice about living with Alzheimer's disease.

Read more about living well with dementia

Advance care planning

People with dementia often live for many years after their diagnosis. However, as it's a progressive condition, it can be helpful and reassuring for both you and your family if you make plans for the future.

Advance care planning means considering, discussing and possibly recording your wishes and decisions for future care. It's about planning for a time when you may not be able to make some decisions for yourself.

In the earlier stages of the disease, you should have the opportunity to discuss with health professionals and your family about the future. This may involve the use of:

Palliative care

Although the outlook is variable, dementia is a life-limiting illness and can begin to affect multiple body systems in the later stages.

End of life care, or palliative care, provides support for people with an incurable illness, so they're able to live as well and as comfortably as possible until their death. It also involves support for family members. Care may be provided at home, a hospice, a care home or hospital.

For people nearing the end of life, their care team should assess their needs, make them feel comfortable and allow them to die with dignity in a place of their choosing.

Read more about palliative care

Telecare Self-Check online tool

Visit the Telecare Self-Check online tool to find the right support for you in your area. This easy to use online tool allows you to find helpful information on telecare services that could help you live independently at home for longer.

Preventing Alzheimer's disease

As the exact cause of Alzheimer's disease is still unknown, there's no way to prevent the condition. However, there are steps you can take that may help to delay the onset of dementia.

Reducing your risk of cardiovascular disease

Cardiovascular disease has been linked with an increased risk of Alzheimer's disease and vascular dementia.

You may be able to reduce your risk of developing these conditions – as well as other serious problems, such as strokes and heart attacks – by taking steps to improve your cardiovascular health, including: 

Read more about preventing dementia

Staying mentally active

There's some evidence to suggest that rates of dementia are lower in people who remain as mentally, physically and socially active as possible throughout their lives, as well as among those who enjoy a wide range of different activities and hobbies.

It may be possible to reduce your risk of Alzheimer's disease and other types of dementia by:

  • reading
  • writing for pleasure
  • learning foreign languages
  • playing musical instruments
  • taking part in adult education courses
  • playing tennis
  • playing golf
  • swimming
  • group sports, such as bowling
  • walking

Interventions such as "brain training" computer games have been shown to improve cognition over a short period, but research hasn't yet demonstrated whether this can prevent dementia.

Future research

Research into Alzheimer's disease is continuing. As more is revealed about the condition, other ways to treat or prevent it may be found.

Participation in research is important and helps to improve dementia care and support for people with dementia, plus their carers and families.

You can read about ongoing dementia research on the Alzheimer's Research UK website. You can also ask your local memory clinic about projects taking place.

The National Institute for Health and Care Excellence (NICE) has advised that there isn't evidence to support the use of the following to prevent dementia:

Last updated:
13 February 2023