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Alzheimer's disease

9-minute read

Key facts

  • Alzheimer’s disease is a type of dementia that affects a person’s thinking, behaviour and ability to perform everyday tasks.
  • Alzheimer’s disease is associated with a build-up of certain proteins and chemicals in the brain, which leads to dementia symptoms that worsen over time.
  • While Alzheimer’s disease is more common in older Australians, it is not a normal part of ageing.
  • There is no cure for Alzheimer’s disease, but some medications and the learning of new behaviours can help relieve symptoms and improve quality of life.
  • See a doctor for a full assessment if you or someone you care about experiences memory loss, difficulty with familiar tasks or language, or changes in mood or personality.

What is Alzheimer’s disease?

Alzheimer’s disease is the most common type of irreversible dementia (gradual loss of memory, intellect, rational thought and social skills). Nearly 7 out of 10 people with dementia have the Alzheimer’s type.

While Alzheimer’s disease affects up to 1 in 10 Australians over 65 years of age, and up to 3 in 10 Australians over 85, it is not a normal part of ageing.

The brain contains millions of brain cells (neurons) that organise how the brain stores memories, learns habits and shapes our personality. Signals pass along the connections between brain cells in the form of chemicals called neurotransmitters. Alzheimer’s disease affects these cells and chemicals, disturbing memory, impairing thinking and causing behaviour changes over time. People with Alzheimer’s disease eventually need long-term care and support.

There are 2 main types of Alzheimer’s disease:

  • Sporadic Alzheimer’s is the most common form and usually occurs after age 65. Its cause is not fully understood.
  • Familial Alzheimer’s (sometimes referred to as 'hereditary') is caused by a very rare genetic condition and results in dementia, usually in people in their 40s and 50s. This is known as younger onset dementia.

What are the symptoms of Alzheimer’s disease?

Early on, Alzheimer’s disease may be hard to notice. The first signs are usually memory loss and difficulty finding the right words for everyday things. However, many people have trouble with memory but don’t have Alzheimer’s — so it’s important to visit a doctor to work out the exact cause of memory problems.

Other common symptoms of Alzheimer’s disease include:

  • vagueness in daily conversation
  • lack of enthusiasm for activities you once enjoyed
  • taking longer to do regular tasks
  • forgetting well-known people or places
  • difficulty processing questions and instructions
  • a decline in social skills
  • unpredictable emotions

Alzheimer’s disease is sometimes classified into 3 stages, based on the severity of symptoms:

  1. Mild Alzheimer’s disease: early signs of dementia, no additional support is usually needed.
  2. Moderate Alzheimer’s disease: symptoms are difficult to cope with and support is likely to be required.
  3. Advanced Alzheimer’s disease: continuous care in all daily activities may be needed.

Symptoms will progress differently between people, depending on what areas of the brain are affected. A person’s symptoms may also change from day to day and can become worse with stress, illness or tiredness.

What causes Alzheimer’s disease?

Several processes occur in Alzheimer’s disease, including amyloid plaque deposits, neurofibrillary tangles and neuronal death.

  • Amyloid plaques are deposits outside the brain cells — they prevent the brain from passing signals properly.
  • Neurofibrillary tangles are deposits inside the brain cells — they kill the cells by blocking off food and energy, causing dementia that worsens over time.
  • Neuronal death causes shrinking in the outer layer of the brain (the cortex) which is vital to memory, language and judgement — Alzheimer’s disease is characterised by this shrinkage.

In most cases, scientists are still unsure of what triggers the formation of plaques, tangles and other chemical changes associated with sporadic Alzheimer's disease. Suspected causes include environmental factors, chemical imbalances or the body’s own immune system.

Alzheimer’s disease tends to target the outer part of the brain first, which is associated with learning and short-term memory. As the disease progresses deeper into the brain, other functions are affected and symptoms get worse.

For people with familial Alzheimer’s disease, mutations in 3 genes have been found to increase the production of amyloid plaques that damage the brain. There are other 'risk-factor genes' that may increase a person's chance of getting Alzheimer’s disease earlier in life.

How is Alzheimer’s disease diagnosed?

Unfortunately, there is no single test that can confirm Alzheimer’s disease. A diagnosis comes after careful assessment. This may involve:

  • a detailed medical history
  • a complete physical and neurological examination
  • tests to check intellectual function
  • a psychiatric assessment
  • neuropsychological tests
  • urine and blood tests
  • medical imaging, such as an MRI scan to assess shrinking of the brain

After eliminating other possible causes of symptoms (such as vascular dementia, nutritional deficiencies or depression), a clinical diagnosis of Alzheimer’s can be made.

An early diagnosis allows your doctor to work out if there is another cause of your symptoms that may be treatable. If a diagnosis of Alzheimer’s disease is most likely, you can start to discuss medical treatment and further assistance to help slow the degenerative process.

How is Alzheimer's disease treated?

Although there is no cure, certain treatments may improve symptoms for a time. Many people with Alzheimer’s disease also learn ways to cope with their symptoms, and improve their quality of life.


A group of medicines called cholinergic drugs may temporarily improve cognitive symptoms of mild-to-moderate Alzheimer’s disease. These work by increasing the level of a brain chemical called acetylcholine, which helps to restore communication between brain cells.

Other medications help to relieve behavioural symptoms such as sleeplessness, agitation, anxiety and depression. These treatments don’t treat Alzheimer’s disease directly but can help improve quality of life.

Lifestyle changes

Where possible, a person with Alzheimer’s disease should try to maintain normal social contact with friends and family, exercise regularly and engage in activities that stimulate the brain. If you have any concerns about safety (for example, driving skills) see your doctor for advice.

Other interventions

If you care for someone with Alzheimer’s disease, it may be helpful to make changes to their home environment to help them feel less disoriented in daily life. For example, you could add clear instructions on how to open doors, or install alert devices if the person is prone to getting lost. Check out Dementia Australia’s help sheets on creating a dementia-friendly environment.

Can you prevent Alzheimer’s disease?

There is no sure way to prevent Alzheimer’s disease. However, you can reduce the risk of Alzheimer’s disease by caring for your health:

  • your heart — what’s good for your heart is good for your brain so stick to a healthy diet and don’t smoke
  • your body — regular physical activity increases blood flow to the brain so maintain an active lifestyle
  • your mind — an active mind helps build brain cells and strengthens their connections so socialise, do things such as puzzles and crosswords, and learn new things, such as a language

What are some complications of Alzheimer’s disease?

Alzheimer’s disease is an irreversible form of dementia. The rate of progression differs between people: some people have it only in the last 5 years of their life, while others may have it for as long as 20 years. Alzheimer’s disease eventually leads to complete dependence and increasing frailty. This means a secondary illness, such as pneumonia, may eventually cause death.

Other complications of Alzheimer’s disease may include:

  • an inability to complete daily tasks such as planning meals and managing money
  • a tendency to wander from home
  • personality changes such as anxiety, depression and irritability that make relationships more difficult
  • delusions and hallucinations in advanced stages of the disease

Caring for someone with Alzheimer’s disease

Caring for someone with Alzheimer’s disease can be hard — but also rewarding. Your emotional and physical support will be a great help when the person's world seems confusing and hostile. Take advantage of the community support that’s available for people with Alzheimer’s disease, their families and carers.

Coordinate their care

Because Alzheimer’s disease gets progressively worse, your loved one will need more care as time goes on. It can be helpful to designate one person who coordinates care and helps them put together a care plan.

Plan ahead

It is wise to plan early for the future. Encourage the person to arrange for a trusted person to manage their affairs through a power of attorney, and to draw up an advanced care directive explaining what treatments they would prefer if they become unable to give consent later on.

Care for yourself

Looking after a loved one with Alzheimer’s disease can be tough and draining. Make sure you spend time socialising and meeting other people. Find activities and interests you can draw encouragement from. Give yourself space to rest, accept and appreciate your loved one.

Resources and support

For more information and support, try these resources:

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Last reviewed: August 2020

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