About dementia


The information in this section defines dementia, describes the symptoms and causes of dementia and explains the difference between normal memory problems and dementia.

What is dementia?

  • Dementia describes a collection of symptoms caused by disorders affecting the brain. It is not one specific disease.
  • Dementia can affect thinking, memory and behaviour. Brain function is affected enough to interfere with someone’s normal social or working life.
  • No two people experience dementia in the same way.
  • It is essential to get a medical diagnosis when symptoms first appear.
  • People often lead active and fulfilling lives for many years after their diagnosis.

Signs and symptoms of dementia

Early signs of dementia can be subtle and may not be immediately obvious.

Common symptoms include:

  • memory loss
  • changes in planning and problem-solving abilities
  • difficulty completing everyday tasks
  • confusion about time or place
  • trouble understanding what we see (objects, people) and distances, depth and space in our surroundings
  • difficulty with speech, writing or comprehension
  • misplacing things and losing the ability to retrace steps
  • decreased or poor judgement
  • withdrawal from work or social activities
  • changes in mood and personality.

Diagnosing dementia

A number of conditions produce symptoms similar to dementia. These can often be treated. They include some vitamin and hormone deficiencies, depression, medication effects, infections and brain tumours.

It is essential to talk to your doctor when symptoms first appear. If you feel comfortable, take a relative or friend with you.

If the symptoms are caused by dementia, an early diagnosis means early access to support, information and, if it is available, medication.

If symptoms are not caused by dementia, early diagnosis will be helpful to treat other conditions.

How is dementia diagnosed

Who gets dementia

Dementia can happen to anybody, but the risk increases with age.

It depends on a combination of age, genes, health and lifestyle.

  • Over the age of 65, dementia affects almost one person in 10.
  • Over the age of 85, dementia affects three people in 10.
  • People under the age of 65 can develop dementia (called ‘younger onset dementia’), but it is less common.
  • Dementia can sometimes be hereditary, but this is quite rare.

Dementia is not a normal part of ageing.

What causes dementia

Many different conditions can cause dementia. In most cases, why people develop dementia is unknown.

The most common types of dementia are:

Read more about different forms of dementia.

Seeking support

Dementia is progressive. Symptoms often begin slowly and gradually worsen over time.

There is no known cure for dementia. There are healthcare professionals, medications and other therapies that can help with some symptoms, and support you to look after your health and wellbeing.

Support is vital for people living with dementia. The help of families, friends and carers can make a positive difference to managing the condition and living well.

Further help