Dementia is caused by different diseases that affect the brain. Alzheimer’s disease is the most common of these diseases. Some other common types of dementia include vascular dementia and dementia with Lewy bodies.
This means that dementia is not a disease in its own right. Dementia is the name for a group of symptoms that commonly include problems with memory, thinking, problem solving, language and perception.
While there is a relationship between dementia and Alzheimer’s disease, there are key differences between the two.
What is dementia?
When a person receives a dementia diagnosis they should also learn what type of dementia they have. This is not always the case, and sometimes the term 'dementia' is used to describe the symptoms they may be experiencing. These symptoms might include memory loss or difficulties with language or concentration.
Dementia is caused by diseases which damage the brain by causing a loss of nerve cells. Alzheimer’s disease is one specific cause of dementia (and the most common). Some other causes of dementia include:
- Vascular dementia, where a lack of oxygen to the brain causes nerve cells to die. This can be caused by a stroke, a series of mini strokes or a disease of the small blood vessels in the brain
- Mixed dementia, where someone has more than one type of dementia and a mix of symptoms
- Dementia with Lewy bodies, where abnormal structures – Lewy bodies – form in the brain and cause the death of nerve cells
- Frontotemporal dementia, where clumps of abnormal protein form in front and side parts of the brain and cause the death of nerve cells.
The symptoms that someone with dementia experiences depends on the damaged parts of the brain and the disease causing the dementia. Dementia is progressive which means it will get worse over time.
Listen to our helpsheet for a summary of the important information you might need to know about dementia.
What is Alzheimer’s disease?
Alzheimer’s disease is a physical disease that affects the brain. Abnormal structures called ‘plaques’ and ‘tangles’ build up inside the brain. These disrupt how nerve cells work and communicate with each other, and eventually cause them to die.
There is also a shortage of some important chemicals in the brain of someone with Alzheimer’s disease. Reduced levels of these chemicals mean that messages don’t travel around as well as they should.
Alzheimer’s disease usually begins gradually with mild memory loss. The person may have difficulty recalling recent events or learning new information. Other symptoms may include difficulties finding the right words, solving problems, making decisions, or perceiving things in three dimensions.
As Alzheimer’s progresses, problems with memory loss, communication, reasoning and orientation become more severe. The person will need more day-to-day support from those who care for them.
There is currently no cure for Alzheimer’s disease. However, treatments may temporarily ease some symptoms or slow down their progression in some people.
Does Alzheimer’s Society support people with dementia, as well as Alzheimer’s disease?
Yes, we do! Find out how Alzheimer's Society can support you.
Until the day we find a cure, we’re striving to improve the lives of those affected by Alzheimer’s disease and all kinds of dementia.