The information on these pages is for anyone who is concerned about symptoms of dementia, and for those who would like more information about how dementia is diagnosed. Anyone concerned about their health should speak to their GP as soon as possible.

Worried about memory and thinking problems?

Most of us forget things every day. We might forget the name of someone we just met, where we put our keys or why we walked into a room. People of all ages experience these things, although many people find they get more common with age, or they may worry more about them as they get older. However, this type of forgetfulness is not necessarily a sign of dementia.

We can also experience problems with our thinking from time to time. We might find it hard to concentrate on something we are trying to do, or struggle to follow a conversation we are having. Some people might find they struggle with words, or when speaking to others.

While it can be normal to experience difficulties from time to time, memory, thinking and communication problems that start to have an effect on our everyday life may be a sign of something more serious. Ongoing symptoms can have many causes, including:

  • infections
  • vitamin deficiencies
  • an underactive thyroid
  • stress, anxiety, and depression
  • some medications you might be taking for other health conditions.

In some cases, however, ongoing memory, thinking and communication problems can be a sign of dementia.

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What is dementia?

The word dementia is used to describe a group of symptoms. These include changes in memory, thinking, judgement, emotions, and language. When someone develops dementia these changes can be very subtle, but over time they get worse. Symptoms of dementia will start to have an impact on a person’s everyday life, making daily activities more difficult to do.

Dementia is not a disease itself; it is caused by various different underlying diseases that affect the brain. Alzheimer’s disease is the most common cause of dementia. Other types of dementia include vascular dementia, dementia with Lewy bodies and frontotemporal dementia.

Most of the diseases that cause dementia damage the brain slowly over time. As this damage spreads and gets worse this causes problems with the way our brains work, giving rise to the symptoms of dementia. The exact symptoms someone experiences will depend on the underlying disease and the areas of the brain affected. However, memory loss, changes in mood, and thinking problems can be some of the first noticeable symptoms in many types of dementia. It is also possible for dementia to develop suddenly, for example after a serious stroke.

Discussion between two people

Frequently asked questions

If you have questions about dementia, or getting a diagnosis you can contact the Dementia Research Infoline on 0300 111 5111 or email

lady wearing glasses

Problems with your memory?

Find out more about symptoms of dementia and how to get a diagnosis through your GP.

Order health information

Alzheimer’s Research UK has a wide range of information about dementia. Order booklets or download them from our online form.


This information was updated in August 2021 and is due to be reviewed in August 2023, 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.

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Dementia Research Infoline

Want to know more about current research? Keen to get involved in research projects?

Contact the Dementia Research Infoline,

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0300 111 5 111