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What is dementia Worried about someone Causes Prevention Treatment & research
What is dementia symptoms overview
About Dementia · Overview

What is Dementia?

? 5 min readReviewed: March 2024
Key Points
  • Dementia is a syndrome linked to an ongoing decline in brain function
  • It affects more than just memory — it can change speech, thinking, feelings and behaviour
  • Dementia is not a natural part of ageing
  • Alzheimer's disease and vascular dementia together make up most cases
  • More than 944,000 people in the UK currently live with dementia

Understanding Dementia

It's normal for memory to be affected by stress, tiredness, certain illnesses, and some medicines. But if you're becoming increasingly forgetful, particularly if you're over 65, it's worth talking to a GP about the early signs of dementia. Occasional memory lapses are one thing, but if memory problems are affecting daily life, or worrying you or someone you know, it's time to get help.

Dementia isn't only about memory — it's a syndrome (a group of related symptoms) linked to an ongoing decline in brain function, and can also affect how someone speaks, thinks, feels, and behaves. Importantly, dementia is not a natural part of ageing. People often confuse Alzheimer's disease with dementia generally — Alzheimer's is actually a specific type of dementia, which together with vascular dementia makes up most cases.

Symptoms of Dementia

Symptoms can include problems with memory, thinking speed, mental sharpness, language (such as using the wrong words or struggling to speak), understanding, judgement, movement, mood, and everyday tasks. People with dementia can lose interest in activities they used to enjoy, and may find it harder to manage their behaviour, emotions, or social relationships. Personality changes are also common, sometimes including a loss of empathy, and some people experience hallucinations, seeing or hearing things others don't.

Because dementia can affect memory and understanding, it can sometimes look — quite wrongly — as though someone is lying or deliberately ignoring a problem, when in fact they may genuinely not remember or understand what's happening. Planning and organising often become harder too, along with maintaining independence, so people with dementia usually need help from family or friends, including with decision-making. Symptoms typically worsen over time, and in the later stages, people lose the ability to care for themselves or communicate.

Why Diagnosis Matters

There's no cure for dementia at the moment, but an early diagnosis means progression can sometimes be slowed, helping someone maintain their mental abilities for longer. Diagnosis also opens the door to the right treatment and support, and helps both the person and those close to them prepare for the future. With the right treatment and support, many people go on to live active, fulfilling lives with dementia.

How Common is Dementia

More than 944,000 people in the UK currently live with dementia — around 1 in 11 people over 65. As people live longer, this number is rising, and it's estimated more than 1 million people in the UK will have dementia by 2030.

Page last reviewed: 6 March 2024  ·  Next review due: 6 March 2027
Worried someone has dementia signs support
About Dementia · Worried About Someone

Worried Someone Has Dementia?

? 5 min readReviewed: March 2024

Signs Worth Noticing

If someone you know is becoming increasingly forgetful, gently encourage them to see a GP about early signs of dementia — there are other explanations for memory loss too, but catching dementia early means its progress can sometimes be slowed. Alongside memory problems, other signs can include growing difficulty with tasks needing concentration or planning, changes in personality or mood, periods of confusion, and trouble finding the right words or following conversations.

Offering to go with your friend or relative to see a GP can be a real support — you can help them recall what's discussed afterwards too. A GP will ask how symptoms have developed over time, and may carry out a memory test, physical exam, and blood tests to rule out other causes. If other explanations are ruled out, they may refer your friend or relative to a memory clinic or specialist service for further assessment.

How to Start the Conversation

Talking about memory loss and the possibility of dementia can be difficult — the person involved may feel confused, unaware anything's wrong, worried, or find it hard to accept. Before raising it, it can help to think about what might be stopping them from seeing a GP, whether they've mentioned any problems themselves, whether they see it as simply part of ageing, whether they're frightened about what it could mean, whether they feel there's no point seeking help, whether you're the right person to raise it, and whether they'd find it reassuring if you offered to come with them.

When you do talk to them, choose somewhere familiar and unthreatening, and allow plenty of time so the conversation doesn't feel rushed. If they don't want to see a GP, UK dementia charities offer support from specialist nurses and advisers — Dementia UK's Admiral Nurse Dementia Helpline (0800 888 6678) and the Alzheimer's Society's dementia support line (0333 150 3456) are both good starting points.

If the Diagnosis is Dementia

A dementia diagnosis can come as a shock, but it's the first step towards getting the information, help and support needed to manage symptoms, and towards making plans for the future together.

Page last reviewed: 6 March 2024  ·  Next review due: 6 March 2027
Causes of dementia types Alzheimer's vascular
About Dementia · Causes

Causes of Dementia

? 5 min readReviewed: March 2024

What Happens in the Brain

Dementia isn't a single disease — it's a term describing symptoms that occur when brain function declines, caused by a range of different underlying diseases. Many of these are linked to an abnormal build-up of proteins in the brain, which stops nerve cells working properly and eventually causes them to die, leading affected areas of the brain to shrink.

Alzheimer's Disease

Alzheimer's disease, the most common form of dementia, is thought to be caused by an abnormal build-up of two proteins, amyloid and tau, forming plaques around brain cells and tangles within them. As brain cells become affected, levels of a chemical messenger called acetylcholine drop, particularly in Alzheimer's — medicines like donepezil work by boosting acetylcholine levels, which can help improve symptoms, though they aren't a cure. The areas of the brain affected first, such as the hippocampus (involved in forming new memories), explain why memory problems are often an early symptom.

Vascular Dementia

Vascular dementia is caused by reduced blood flow to the brain, damaging and eventually killing brain cells — this can result from narrowed or blocked blood vessels in the brain, a single stroke, or many small "mini strokes" causing widespread but subtle damage. Not everyone who has a stroke goes on to develop vascular dementia.

Dementia with Lewy Bodies and Frontotemporal Dementia

Dementia with Lewy bodies is caused by tiny clumps of a protein called alpha-synuclein forming inside brain cells, damaging how they function and communicate — it's closely related to Parkinson's disease and shares some symptoms, including movement difficulties and a higher fall risk. Frontotemporal dementia, an important cause in younger people (most often diagnosed between 45 and 65), is caused by abnormal protein clumping in the frontal and temporal lobes, and is more likely to run in families than other common causes of dementia.

Mixed and Rarer Causes

Mixed dementia involves more than one type together, most often vascular dementia combined with Alzheimer's disease, and it can be hard to know how much each is contributing. Rarer causes include Huntington's disease, corticobasal degeneration, progressive supranuclear palsy, and normal pressure hydrocephalus.

Mild Cognitive Impairment

Mild cognitive impairment (MCI) isn't itself a cause of dementia — it describes minor memory and thinking difficulties, such as forgetfulness, trouble concentrating, or difficulty planning, that aren't severe enough to affect daily life. MCI can stem from an underlying, treatable condition such as depression, anxiety, or a thyroid problem, and symptoms often improve once that's addressed. In some cases, though, people with MCI are at increased risk of later developing dementia, usually due to Alzheimer's disease.

Page last reviewed: 6 March 2024  ·  Next review due: 6 March 2027
Preventing dementia risk factors lifestyle
About Dementia · Prevention

Can Dementia Be Prevented?

? 5 min readReviewed: March 2024

Reducing Your Risk

There's no certain way to prevent every type of dementia, but good evidence shows a healthy lifestyle can help reduce your risk as you get older — largely because what's good for your heart is also good for your brain. Some risk factors, like age and genes, can't be changed, and dementia itself isn't a natural part of ageing. Air pollution, hearing loss, untreated depression, loneliness or social isolation, and sitting for long periods have also been identified as possible risk factors. Research suggests around 4 in 10 dementia cases could potentially be prevented by addressing the risk factors within our control.

Diet, Weight and Exercise

A diet high in saturated fat, salt and sugar, and low in fibre, raises the risk of high blood pressure, high cholesterol, being overweight, and type 2 diabetes — all linked to a higher dementia risk. Following the Eatwell Guide for a balanced diet can help. Being overweight also raises blood pressure and type 2 diabetes risk, and even losing 5 to 10% of excess weight can help reduce dementia risk if you're carrying extra weight. Lack of regular exercise raises the risk of cardiovascular disease, excess weight, and type 2 diabetes, and inactive older adults are more likely to have memory or thinking difficulties — aiming for at least 150 minutes of moderate aerobic activity a week, plus strength exercises twice a week, and simply sitting less overall, can all help.

Alcohol, Smoking and Mood

Drinking excessive alcohol raises the risk of stroke, heart disease, some cancers, and damage to the nervous system including the brain — sticking to no more than 14 units a week, spread across at least 3 days with several alcohol-free days, is the recommended limit. Smoking narrows the arteries and raises blood pressure and cardiovascular disease risk; quitting can help reduce dementia risk too, and the NHS Smokefree helpline (0300 123 1044) offers support. The relationship between depression and dementia is complex — untreated depression appears to raise dementia risk, while depression can also be part of dementia's own symptom picture, and low mood or anxiety can reduce social and mental engagement either way. Talking to a GP about low mood, and accessing support such as CBT or talking therapies, can help.

NHS Health Checks

The free NHS Health Check, offered every 5 years to people aged 40 to 74 without existing heart disease, diabetes, kidney disease, or a history of stroke, can help spot early signs of conditions linked to higher dementia risk, such as coronary heart disease, diabetes, kidney disease, and stroke. If you're over 65, you'll also be given information on dementia symptoms to watch for and advice on lowering your risk. If you haven't been invited for a check, ask your GP surgery.

Page last reviewed: 6 March 2024  ·  Next review due: 6 March 2027
Dementia treatment medicines research cure
About Dementia · Treatment & Research

Treatment, Support and Ongoing Research

? 5 min readReviewed: March 2024

Medicines for Dementia Symptoms

There's no cure for dementia yet, but medicines and other treatments can help manage symptoms. Acetylcholinesterase inhibitors, such as donepezil, rivastigmine and galantamine, are used for mild to moderate Alzheimer's disease (donepezil is also used for more severe cases), and there's evidence they can help with dementia with Lewy bodies, Parkinson's disease dementia, and mixed Alzheimer's-vascular dementia too — common side effects like nausea usually settle after a couple of weeks. Memantine is used for moderate to severe Alzheimer's, dementia with Lewy bodies, and mixed dementia, and suits people who can't tolerate the medicines above; side effects like headaches or dizziness are usually temporary.

Related conditions that can affect dementia symptoms — such as stroke, heart problems, diabetes, high blood pressure, high cholesterol, kidney disease, and depression — are important to diagnose and treat alongside dementia itself.

Managing Challenging Behaviour

In later-stage dementia, some people develop behavioural and psychological symptoms, including increased agitation, anxiety, wandering, aggression, delusions or hallucinations — coping strategies can help, but if these aren't enough, antipsychotic medicines such as risperidone or haloperidol may be prescribed for persistent aggression or extreme distress, always at the lowest effective dose, for the shortest time, with regular review, and only decided by a consultant psychiatrist. Antidepressants may also be used if depression seems to be an underlying factor.

Complementary remedies such as ginkgo biloba, curcumin, or coconut oil are sometimes used, but there isn't enough evidence to confirm they work, and some can interact with prescribed medicines — always check with a doctor before trying one, and never use them as a substitute for prescribed treatment.

Non-Medicine Approaches

Cognitive stimulation therapy involves group activities designed to support memory, problem-solving and language, and has good evidence for people with mild to moderate dementia. Cognitive rehabilitation involves working with a professional, such as an occupational therapist, alongside a relative or friend towards a personal goal, using stronger parts of the brain to support weaker ones — helpful particularly in earlier stages. Reminiscence and life story work, using photos, keepsakes, or music to talk through past events and experiences, can improve mood and wellbeing, and help focus on someone's skills and identity rather than just their diagnosis.

Research Towards a Cure

Because dementia is caused by several different diseases, a single cure is unlikely, but research into treatments for conditions like Alzheimer's, frontotemporal dementia, and dementia with Lewy bodies continues to advance. Current research areas include using stem cells to study how brain damage begins, immunotherapy approaches such as vaccines or antibody treatments targeting abnormal brain proteins (with some promising early results), gene-based therapies targeting the genes involved, and "repurposing" existing medicines — originally developed for conditions like type 2 diabetes or high blood pressure — to see if they help with dementia too.

Researchers are also working on identifying who's at risk before symptoms appear, including specialised PET brain scans and long-term studies like PREVENT, which follows people in their 40s and 50s at higher genetic or family risk. In the meantime, addressing modifiable risk factors in mid-life — such as blood pressure, diabetes, weight and smoking — could reduce dementia risk by up to 30%, making prevention just as important as the search for a cure.

If you have a dementia diagnosis, or are worried about memory problems, you (or carers) can take part in research through the NHS Join Dementia Research website, helping scientists better understand the condition and develop future treatments and care approaches.

Page last reviewed: 6 March 2024  ·  Next review due: 6 March 2027