Dementia with Lewy bodies
Dementia information
Dementia is caused by different diseases. Dementia with Lewy bodies is the third most common disease that causes dementia.
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What is dementia with Lewy bodies?
The word dementia is used to describe a group of symptoms. These include:
- memory loss
- confusion
- changes to communication
- mood and behaviour.
These symptoms affect day-to-day life.
Dementia is caused by different diseases that affect the brain. Dementia with Lewy bodies is the third most common type of dementia after Alzheimer’s disease and vascular dementia.
For every 20 people who have dementia, between three and four will have dementia with Lewy bodies. This means that around 100,000 people in the UK have this type of dementia.
Dementia with Lewy bodies is often shortened to DLB.
What causes dementia with Lewy bodies?
In DLB, a protein called alpha-synuclein changes shape and sticks together inside brain cells. The clumps it forms are called Lewy bodies, and may contain other abnormal proteins.
As DLB progresses, more abnormal proteins build up. This is linked to nerve cell damage and affects how brain cells communicate with each other.
In DLB, the nerve cells that are affected are in areas of the brain that control our thinking, memory, and body movement.
Dementia with Lewy bodies, Parkinson's disease and Parkinson's disease dementia
Dementia with Lewy bodies is closely related to Parkinson’s disease (PD).
The build-up of Lewy bodies is also found in Parkinson’s - but in different areas of the brain.
Symptoms of Parkinson's include movement problems, such as being slow and stiff, and sometimes having tremors.
People who have Parkinson’s disease can go on to develop dementia. This is known as Parkinson's disease dementia (PDD).
Dementia with Lewy bodies and Parkinson’s disease dementia can affect people in similar ways. The diagnosis that someone receives will depend on which symptoms started first.
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Dementia with Lewy bodies (DLB)
Memory problems and dementia symptoms appear before or at the same time as movement problems.
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Parkinson's disease dementia
Parkinson's movement problems are experienced for a year or more before memory and thinking problems appear.
It is not always easy to tell if a person has DLB or PDD. That's because it's not always clear exactly when memory and thinking problems start.
What is Lewy body dementia?
Lewy body dementia is a term that describes both DLB and PDD and can be used in these situations. It can also be useful to group these conditions using the term Lewy body dementia as there are many similarities, both in symptoms and in the needs of people with the conditions and their families.
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You can find out more about current diagnosis and treatments for each type of dementia on the following pages:
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This information was updated in December 2025 and is due to be reviewed in December 2027. It was written by Alzheimer’s Research UK’s Information Services team with input from lay and expert reviewers. Please get in touch if you’d like a version with references or in a different format.
This information is produced with support from The Perfume Shop who had no input into the content.
