Less common dementias
Dementia can manifest as a symptom of other diseases, infection or injury. Less common types of dementia include:
- Parkinson's disease dementia
- Dementia due to the effect of alcohol and other substances
- Dementia in Huntington's disease
- HIV associated dementia
- Creutzfeldt-Jakob disease
- Chronic traumatic encephalopathy
- Childhood dementia.
The number of people in Australia living with these less common types of dementia is not known. There are some data on hospitalisations and deaths where rarer dementia types are recorded, however, these are limited and should be interpreted with caution as coding of dementia type can be inconsistent and can vary by region of residence (AIHW 2023b; Waller et al. 2021).
More information on each of these dementia types can be found in the following sections. For more information about hospitalisations and deaths for people with dementia, see Hospital care and Deaths and disease burden.
Parkinson's disease, Parkinson's disease dementia, and dementia with Lewy bodies are three overlapping disorders that are forms of Lewy Body disease. They share similarities in the ways by which they damage the brain at the cellular level and in the symptoms a person may experience. For more information, see Lewy body disease.
Globally, the prevalence of Parkinson's disease has been increasing (Wu et al. 2025) and an estimated 20%–40% of people with Parkinson's disease also have dementia (Åström et al. 2022).
In Australia:
- prevalence estimates for Parkinson's disease vary widely (Deloitte Access Economics 2015; Parkinson's NSW 2024)
- in 2023, among people who had dementia recorded as an associated cause of death, Parkinson's disease was the leading underlying cause of death (UCOD) for people aged 65–74 (Table S3.8)
- in 2023, there were over 680 deaths with Dementia in Parkinson's disease recorded in people aged 30 and over (Table S3.4c)
- in 2023, there were 480 deaths due to Lewy Body dementia in people aged 30 and over (Table S3.4b)
- between 2003 and 2024, the rate of fatal burden of disease (years of life lost) due to Parkinson's disease increased by 63% for men and 24% for women (AIHW 2024a)
- Dementia in Parkinson's disease was recorded as the dementia type in 1.3% of hospitalisations due to dementia (2.0% for men, 0.7% for women) in 2023–24 (Table S9.3)
- Lewy Body dementia was recorded as the dementia type in 2.4% of hospitalisations due to dementia (3.0% for men, 1.8% for women) in 2023–24 (Table S9.3).
For more information about Parkinson’s disease, see Parkinson’s disease in Australia.
The use of alcohol and other harmful substances can have long-term impacts on brain health (Dementia Australia 2018).
In 2023, there were 35 deaths due to Dementia due to the effect of substances in people aged 30 or over (Table S3.4b).
In 2023–24, Dementia due to the effect of substances was recorded as the dementia type in less than 1% of hospitalisations due to dementia (1.0% for men, 0.6% for women) (Table S9.3).
For more information, see Alcohol related dementia.
Huntington’s disease is an inherited genetic condition that progressively affects the nervous system and causes dementia. It can occur at any age, but people usually start experiencing symptoms in young-middle aged adulthood.
In Australia:
- an estimated 2,400 Australians were living with Huntington’s disease in 2024 (estimated prevalence rate of 8.9 per 100,000 people, Medina et al. 2022 and AIHW 2025e)
- as at 31 December 2024, there were about 1,100 National Disability Insurance Scheme (NDIS) plans for people diagnosed with Huntington’s disease
- about 40 people with Huntington's disease moved into permanent residential aged care per year between 2013–14 and 2017–18.
- In 2023, there were 9 deaths with Dementia in Huntington’s disease recorded in people aged 30 and over (Table S3.4c).
- In 2023–24, Dementia in Huntington’s disease was recorded as the dementia type in less than 0.1% of hospitalisations due to dementia (Table S9.3).
For more information, see Huntington’s disease.
The human immunodeficiency virus (HIV) can infect brain cells, causing cognitive impairment. The most severe form of impairment is called HIV associated dementia. Since the introduction of combination antiretroviral therapy, HIV associated dementia is rare in high income countries, affecting 2–8% of people living with HIV (Saylor et al. 2016).
For more information, see HIV associated dementia.
Due to low numbers, Dementia in HIV is included in the category 'Other dementia' in 2023–24 hospitalisation data (Table S9.3).
Creutzfeldt-Jakob disease (CJD) is a very rare degenerative brain disease that causes dementia. CJD usually develops spontaneously (called sporadic CJD), but other forms of the disease can be genetically inherited or acquired from external sources.
For more information, see the CJD Support Group Network.
CJD is the most common of the human prion diseases. In Australia, an average of 35 new cases of human prion disease were reported each year between 1993 and 2022 (Stehmann et al. 2023). There has been an increase in the number of cases of sporadic CJD reported over time, likely due to a combination of an ageing population and improved detection.
In 2023–24, Dementia in Creutzfeldt-Jakob disease was recorded as the dementia type in less than 0.1% of hospitalisations due to dementia (Table S9.3).
Chronic Traumatic Encephalopathy (CTE) is a type of dementia caused by repeated head injuries. These injuries may occur while playing sport, or through other forms of head impact such as violent assault, family and domestic violence, frequent falls, or during military service.
For more information, see Chronic Traumatic Encephalopathy dementia.
There is a lack of data on the prevalence and impact of CTE and its causes. Data development initiatives include the National Sports Injury Data Strategy, the Australian Sports Brain Bank and the Australian Veterans Brain Bank.
Childhood dementia results from progressive brain damage and is caused by over 100 rare genetic disorders (Elvidge et al. 2023).
See Childhood dementia for more information.
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