What causes dementia?April 6 2014
Dementia is the result of brain cells being damaged in an ongoing way. This happens as a result of a number of different diseases, sometimes referred to as ‘types’ of dementia. It is not an inevitable part of ageing.
Some of the more common diseases that cause dementia include:
- Alzheimer’s disease (62%): A physical disease caused by changes in the structure of the brain and a shortage of important chemicals that help with transmission of messages.
- Vascular dementia (17%): Caused by problems in the supply of blood to the brain, commonly cause by a stroke or a series of small strokes.
- Mixed dementia (10%): A type of dementia where a person has a diagnosis of both Alzheimer’s disease and vascular dementia.
- Dementia with Lewy bodies (4%): One of the less common forms of dementia, it is caused by irregularities in brain cells. Leading to symptoms similar to Alzheimer’s disease and Parkinson’s disease.
- Rarer causes of dementia (3%): There are many rarer causes diseases and syndromes that can lead to dementia or dememtia-like symptoms, including Corticobasal degeneration and Creutzfeldt-Jakob disease.
- Fronto-temporal dementia (2%): rare when all ages are taken into account but relatively common in people under 65, it is a physical disease that affects the brain. 
Other less common causes of dementia are:
- Huntington’s disease
- Creutzfeldt-Jakob Disease (CJD)
- AIDS related dementia
- Korsakoffs Syndrome
The term ‘Mixed’ is used when dementia has more than one cause. For example a person may have both Alzheimer’s disease and Vascular dementia.