Dementia in Australia

This chapter presents statistics and information on:

• Types of dementia
• What puts someone at risk of developing dementia?
• How is dementia diagnosed?
• Less common dementias
• What care and support is available to people with dementia?

Dementia is not a single specific disease, but rather there are many types of dementia with symptoms in common. These are caused by a range of conditions that impact brain function by damaging brain cells (neurons) and their connections. Dementia is commonly associated with memory loss but can affect speech, cognition, emotional control, behaviour and mobility (WHO 2023).

There is currently no cure for dementia but there are strategies to manage dementia symptoms that can assist in maintaining independence and quality of life for as long as possible.

Irrespective of the type of dementia, as the condition progresses the person living with dementia will experience declining health and will require increasing care – eventually in all aspects of daily living. Many people with dementia experience a steady, gradual decline over several years, but the progression of dementia varies considerably from person to person. 

Types of dementia

Identifying the type of dementia at the time of diagnosis is important to ensure the person receives appropriate treatment and services, and to be better informed about their condition, treatment options and prognosis. However, it is not always straight forward to correctly diagnose the type of dementia based on a person’s symptoms (see How is dementia diagnosed?).

The most common types of dementia include:

• Alzheimer’s disease – a degenerative brain disease caused by build-up of beta-amyloid plaques and neurofibrillary tangles, resulting in brain cell death and shrinkage of the brain. 
• Vascular dementia – mainly caused by haemodynamic (blood flow to the brain) disorders (for example, strokes), thromboembolism (small blood clots that block small blood vessels in the brain), small blood vessel disease in the brain and bleeding into or around the brain.
• Dementia with Lewy bodies – caused by the degeneration and death of brain cells due to the presence of abnormal spherical structures, called Lewy bodies, which develop inside brain cells.
• Frontotemporal dementia – caused by progressive damage to the frontal and/or temporal lobes of the brain due to the abnormal accumulation of proteins in the brain (Dementia Australia 2022; Draper 2013).

For information on the less common types of dementia, see Less common dementias.

It is common to have multiple types of dementia at once – known as ‘mixed dementia’ – with the most common combination being Alzheimer’s disease and vascular dementia. An increased risk of developing dementia is also linked to the presence of other conditions (such as Parkinson’s disease, Huntington’s disease and Down syndrome), prolonged substance abuse and traumatic brain injuries.

The likelihood of developing dementia increases with age, however, dementia is not an inevitable or normal part of the ageing process. Dementia can also develop in people aged under 65, referred to as ‘younger onset dementia’ or in childhood. Refer to Younger onset and childhood dementia for more information.