What is dementia?

Dementia is an umbrella term for a range of progressive conditions that affect the brain.

Each type of dementia stops a person’s brain cells (neurones) working properly in specific areas, affecting their ability to remember, think and speak.

Doctors typically use the word ‘‘dementia’’ to describe common symptoms – such as memory loss, confusion, and problems with speech and understanding – that get worse over time.

Dementia can affect a person at any age but it’s more common in people over the age of 65.

There are over 200 subtypes of dementia. The most common are Alzheimer’s disease, vascular dementia, Lewy body dementia, frontotemporal dementia and mixed dementia.

By 2025, it’s estimated that over one million people in the UK will have a diagnosis of dementia – and almost all of us will know someone living with the condition. Our dementia specialist Admiral Nurses explain the facts you need to know.

Alzheimer's disease

Alzheimer’s disease is the most common type of dementia in the UK. It’s caused by a build-up of proteins in the brain which damage the brain cells’ ability to transmit messages.

The symptoms of Alzheimer’s disease tend to get worse over time. They include:

  • difficulty remembering recent events (often retaining a good memory for past events)
  • poor concentration
  • difficulty recognising people or objects
  • poor organisational skills
  • confusion
  • disorientation
  • slow, muddled or repetitive speech
  • difficulty performing everyday tasks such as cooking, paying bills, and shopping
  • problems with decision-making

There is no cure for Alzheimer’s disease, but medication is available to help slow its progression.

Vascular dementia

Vascular dementia is the second most common type of dementia. It’s caused by problems in the supply of blood to the brain, commonly due to strokes or ‘mini strokes’ called transient ischaemic attacks (TIAs). This causes areas of cell damage in the brain.

Changes in a person’s condition as a result of TIAs or a larger stroke are often sudden and then plateau (level off). But the damage caused often means the person never functions quite the same as they did before.

Vascular damage can also take place in the smaller vessels of the brain (‘small vessel disease’) and symptoms may be more gradual.

The symptoms of vascular dementia are often similar to Alzheimer’s disease, such as memory problems, disorientation and difficulty with communication.

However, symptoms can depend on which area of the brain has been affected and may include specific problems with:

Lewy body dementia

Lewy body dementia is a progressive condition that affects movement and motor control (the ability to control voluntary movements for specific tasks, like walking, getting dressed and using cutlery). Memory is often less affected than with other types of dementia.

A person with dementia with Lewy bodies might:

  • be prone to falls
  • have sudden bouts of confusion
  • have tremors (shaking or trembling, similar to Parkinson’s disease)
  • have trouble swallowing
  • experience disrupted sleep patterns due to intense dreams/nightmares
  • have visual (sight) and auditory (hearing) hallucinations
  • shuffle when they walk
Frontotemporal dementia

Frontotemporal dementia affects the frontal lobes of the brain: the part that controls behaviour, learning, personality and emotions.

It can affect people of all ages, but is more common in people aged 45 to 65 years than in those aged 65 and over.

Frontotemporal dementia can be difficult to diagnose. It’s sometimes confused with depression, stress, anxiety, psychosis or obsessive compulsive disorder (OCD).

Frontotemporal dementia can cause inappropriate social behaviour and a lack of inhibitions. Eating patterns can also be affected, with people suddenly bingeing on food, especially sweet foods.

Mixed dementia

It’s possible to have two types of dementia at the same time, most commonly Alzheimer’s disease and vascular dementia.

A person with mixed dementia will experience a mixture of the symptoms associated with the types of dementia they have.

What is young onset dementia?

Young onset dementia is any type of dementia where symptoms develop before the age of 65. You might hear it described as ‘early onset dementia’ or ‘working age dementia.’ It’s thought that about five percent of people with dementia have young onset dementia.

The most common types of dementia amongst younger people are Alzheimer’s disease, vascular dementia and frontotemporal dementia. Rare and genetically inherited types of dementia like Parkinson’s disease and Huntington’s disease are also more common in younger people.

Problems with language, vision, behaviour and/or personality may be the first symptoms, rather than memory loss. This can result in a delay in diagnosis as the symptoms may be wrongly attributed to another problem such as depression, work stress or relationship difficulties.

Getting a dementia diagnosis

If someone has symptoms of dementia, visit a GP as soon as possible. Some other treatable conditions have similar symptoms, including infections, thyroid problems, circulatory issues, vitamin deficiency, sleep apnoea, stress and depression, and it’s important to rule these out.

The GP should take the person’s medical and family history and ask questions about their concentration, short-term memory, mood, and behaviour changes.

The GP may then request blood tests, an MRI or CT scan to examine the structure of the brain, and/or a chest X-ray to check for any chest conditions that could be causing the symptoms.

They may also refer the person to a memory service/clinic, or to a specialist for further investigation, assessment and possible treatment.

You can read more information about getting a diagnosis here.

Your dementia questions answered

Why does dementia affect each person so differently?

The brain is made up of four lobes: frontal, temporal, parietal and occipital. Each lobe has a different function and depending on which part is damaged by dementia, it can lead to different signs and symptoms.

Frontal lobes control:

  • emotional expression
  • personality
  • problem-solving
  • judgement
  • motor function
  • language
  • motivation
  • social behaviour

Temporal lobes control:

  • memory
  • speech
  • language comprehension
  • auditory (hearing) and visual perception
  • emotional responses
  • face recognition

Parietal lobes control:

  • learnt skills such as reading, writing, calculations and driving
  • object recognition
  • spatial awareness

Occipital lobes control:

  • spatial awareness
  • colour recognition
  • object recognition
  • hand-eye coordination such as picking up items

How can I avoid getting dementia?

You can’t prevent dementia, but there are things that could reduce your risk of developing it:

  • eat a healthy, balanced diet
  • if you’re a smoker, stop smoking
  • avoid drinking too much alcohol
  • ask your GP to test your blood pressure and cholesterol level, and take advice on reducing these if they’re raised
  • stay physically and mentally active: activities like walking, gardening, singing, art, music, reading, puzzles and learning a new language may help

Is dementia hereditary?

Most dementias are not inherited, although Alzheimer’s disease may be more likely if you have a family history of the condition. Genetics are also thought be involved in around 10% of young onset dementia cases. Some rarer causes of dementia can be inherited, like Huntington’s disease.

Why is the number of people with dementia in the UK increasing?

There are over 900,000 people living with dementia in the UK and this is set to rise to over one million by 2025.

As awareness of dementia is increasing, people are more likely to recognise the signs and go to their GP to get a diagnosis.

People are also living for longer, and the risk of developing dementia gradually increases in people over the age of 65: one in six people in their 80s will develop dementia, and over one in three people aged 90 and over.

Support for people with dementia and their carers

Your GP or specialist should be able to provide information about advice and support services in your area, including NHS services, Social Services, charities and voluntary organisations.

Dementia UK’s dementia specialist Admiral Nurses support people with dementia and their families and carers. They work in the community, in some GP practices and NHS hospitals, and in clinics. You can use our website to find Admiral Nurse services in your area or book a virtual appointment.

They also run our Admiral Nurse Dementia Helpline. For any questions or concerns about dementia, you can contact them on 0800 888 6678 (Monday-Friday 9am-9pm, Saturday and Sunday 9am-5pm, every day except 25th December) or email helpline@dementiauk.org.

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Publication date: March 2023
Review date: March 2025