What is dementia?

6. Diagnosing dementia

It is very important for anyone who has problems with their memory or thinking to get a proper assessment. These problems may be caused by a treatable condition such as depression or an infection, rather than dementia. Finding out the cause may allow the person to get the right treatment.

If these problems are because of dementia, getting a diagnosis has many benefits. It provides someone with an explanation for their symptoms, gives them access to treatment, advice and support, and allows them to prepare for the future and plan ahead. Knowing the type of dementia (for example, Alzheimer’s disease or vascular dementia) is also important, partly because it may allow the person to get an appropriate drug treatment.

Dementia will usually be diagnosed by a specialist doctor such as:

  • a psychiatrist – a mental health specialist
  • a geriatrician – a doctor specialising in the physical health of older people
  • a neurologist – someone who concentrates on diseases of the nervous system.

Occasionally a GP or specialist nurse will make the diagnosis, depending on their expertise and training.

There is no single test for dementia. A diagnosis is based on a combination of things:

  • taking a ‘history’ – the doctor talking to the person and someone who knows them well about how their problems developed and how they are now affecting their daily life
  • physical examination and tests (for example, blood tests) to exclude other possible causes of the person’s symptoms
  • tests of mental abilities (for example, memory, thinking) – simpler tests will be carried out by a nurse or doctor, more specialist tests by a psychologist
  • a scan of the brain, if this is needed to make the diagnosis.

A common pattern is for the GP to make an initial assessment and then refer the person to a memory clinic or other specialist service for a more detailed assessment. A specialist doctor will have more expertise in dementia and will be able to arrange more detailed tests and brain scans, if needed. The diagnosis should be communicated clearly to the person and usually those closest to them as well. There should also be a discussion about the next steps.