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What is dementia?

The information below gives an overview of dementia and its various forms. Visit our useful links page for websites for further information.

Although usually associated with getting older, dementia is not an inevitable part of ageing and dementia can occur in younger people (early-onset dementia).


Memory loss


In later life, you may feel that your memory is not as good as it used to be. It's normal for your memory to be affected by age, stress, tiredness, certain illnesses, depression and medications. However, if memory loss is affecting your daily life or is worrying you or someone you know, you should visit your doctor for advice.

Not all memory loss is untreatable. It may be caused by other medical or psychological problems that can be treated.


However, if the memory problems are due to dementia-type illnesses, early diagnosis is key to accessing appropriate treatment and support.


Mild Cognitive Impairment

Sometimes a doctor will assess and diagnose a person as having Mild Cognitive Impairment (MCI). This diagnosis is given when the person has mild memory problems but symptoms are not severe enough to support a diagnosis of dementia. For example, a person may become aware that their memory is not as good as usual or find they are having difficulty concentrating or thinking clearly. Having a diagnosis of MCI does not mean you will go on to develop dementia.



Dementia is a condition associated with a decline in brain function that can affect memory, thought processes, language, understanding and judgement.

Other symptoms may include difficulty communicating, problems with reasoning and carrying out everyday tasks, particularly those which require planning, changes in personality, mood swings and periods of confusion.

Dementia is progressive. This means that symptoms experienced are likely to change and will become more severe over time. However, dementia is not a hopeless condition and some of the difficulties can be prevented or reduced.


The symptoms and experience of dementia can vary greatly from person to person.

How quickly the symptoms deteriorate and the way they develop depends on the cause of the person's dementia, their overall health and other factors.


Dementia is not a life sentence. People with dementia can live positive lives and make a valuable contribution to their communities.

Early diagnosis of dementia

Early symptoms of dementia are often difficult to identify. A person with dementia and those around them may not recognise these symptoms or take them seriously for some time.

Although dementia cannot be cured, with early diagnosis there are ways to slow down the development of the condition and early diagnosis can help people with dementia get the right treatment and support
It is important to talk to your doctor sooner rather than later if you are worried that you or someone you know may have memory problems, so any other medical causes can be eliminated.

There are a number of conditions that cause dementia and some people may have more than one condition at the same time. Follow the links below for an outline description of the most common conditions and their symptoms:


Alzheimer's disease

Vascular dementia

Dementia with Lewy bodies

Frontotemporal dementia

Mixed dementia

Follow the links below to find out more about:


The later stages of dementia

Living well with dementia