Dementia

What is dementia?

Dementia is not a single disease, but an umbrella term for a group of symptoms, including memory loss and difficulties with thinking, language and behaviour, caused by a number of different diseases that damage the brain. It's a progressive condition, meaning symptoms usually get worse over time, but it isn't a natural part of ageing.

Symptoms of dementia

Symptoms vary from person to person and depend on which type of dementia someone has, but they tend to develop gradually and get worse over time. Early symptoms are often mild and may not be noticed by the person experiencing them, though family and friends might notice changes first.

Common early symptoms include:

• memory loss, such as forgetting recent events, names or faces
• difficulty concentrating or following a conversation
• struggling to find the right word
• confusion about time or place
• difficulty carrying out familiar daily tasks, such as working out the right change when shopping
• mood changes, or feeling anxious, sad or angry about the changes you're noticing

As dementia progresses, symptoms usually become more severe. Someone with advanced dementia may not recognise close family or friends, lose the ability to speak, become less able to move around unaided, and need support with eating, drinking, and using the toilet.

Changes to mood and behaviour, including increased agitation, anxiety, or, in some cases, hallucinations, are also common as the condition progresses, and can be distressing for both the person and the people caring for them.

Causes and risk factors

Dementia is caused by different diseases that damage brain cells, stopping different parts of the brain communicating with each other and working as they should. As more brain cells are damaged, the affected areas of the brain gradually shrink.

Age is the strongest risk factor. Dementia mainly affects people over 65, and the risk increases as you get older, though it can affect younger people too. Other things that can increase your risk include high blood pressure, high blood sugar (diabetes), being overweight, depression, hearing or vision loss, poor sleep, a previous brain injury or stroke, smoking, harmful alcohol use, being physically inactive, social isolation, and long-term exposure to air pollution.

Not all memory or thinking problems are caused by dementia, and some are reversible if the underlying cause is treated. Depression, side effects from certain medicines, excessive alcohol use, thyroid problems and vitamin deficiencies can all cause dementia-like symptoms that improve once treated, so it's worth having these ruled out.

Genetics can occasionally play a role. Rare, inherited forms of dementia exist, and some types, such as frontotemporal dementia, are somewhat more likely to run in families, though this isn't the case for most people with dementia.

Are there different types of dementia?

Alzheimer's disease is the most common cause of dementia, responsible for around 60 - 70% of cases according to the World Health Organization, or as much as 60 - 80% according to the Alzheimer's Association. It's caused by a build-up of two proteins, called amyloid and tau, which damage brain cells, particularly in the area of the brain responsible for forming new memories, which is why memory problems are often the first symptom.

Vascular dementia is the second most common type. It's caused by reduced blood flow to the brain, for example after a stroke, a series of small strokes, or narrowing of the blood vessels inside the brain. Not everyone who has a stroke goes on to develop vascular dementia, and memory loss may be less obvious in the early stages than with Alzheimer's disease.

Dementia with Lewy bodies is caused by tiny clumps of protein that build up inside brain cells and disrupt how they work. It's closely related to Parkinson's disease and often causes similar symptoms, such as difficulty with movement, a higher risk of falls, and visual hallucinations.

Frontotemporal dementia is caused by a build-up of proteins in the front and side parts of the brain. It's an important cause of dementia in younger people, most often diagnosed between the ages of 45 and 65, and is somewhat more likely to run in families than other types.

Mixed dementia describes having more than one type at the same time, most commonly Alzheimer's disease together with vascular dementia. There are also several rarer causes, including Huntington's disease and normal pressure hydrocephalus, a build-up of fluid in the brain.

How is dementia diagnosed?

There's no single test for dementia. If you're worried about your memory or another symptom, see a GP, and try to take someone who knows you well, since they may notice changes you haven't.

The GP will ask about your symptoms and how you're managing everyday activities such as washing, cooking and paying bills. They'll examine you and may organise blood and urine tests to rule out other causes of memory problems, such as an underactive thyroid, an infection, or medication side effects, alongside a memory or cognitive test to check for problems with thinking and recall.

If other causes have been ruled out, you may be referred to a specialist, such as a psychiatrist, geriatrician or neurologist, often working in a memory clinic. They may arrange a brain scan, such as a CT or MRI scan, and more detailed memory testing. Most cases of dementia can be diagnosed after these assessments, though it can be harder to pin down the exact type, since symptoms and brain changes can overlap between types.

How is dementia treated?

There's no cure for dementia, and it isn't treated with surgery. Instead, treatment focuses on medicines and support that can help manage symptoms and improve day-to-day quality of life for as long as possible.

For Alzheimer's disease, medicines called acetylcholinesterase inhibitors, such as donepezil, rivastigmine and galantamine, can temporarily improve symptoms in mild to moderate disease. Memantine works differently and is used for moderate to severe Alzheimer's disease, or for people who can't take the other medicines. Both types of medicine can also help some people with dementia with Lewy bodies or mixed dementia, though side effects such as nausea, dizziness or headaches are possible.

Newer medicines, donanemab and lecanemab, have been approved in the United States and work by removing amyloid from the brain, which can reduce the rate of decline in early Alzheimer's disease. Their availability on the NHS is still developing, so it's worth asking your specialist what's currently offered in your area.

If other conditions, such as high blood pressure, high cholesterol or diabetes, are contributing to vascular dementia, treating these can help prevent further damage to the brain.

Alongside medicines, non-drug approaches are just as important. Cognitive stimulation therapy involves group activities and exercises to support memory, problem-solving and language, and has been shown to help people with mild to moderate dementia. Cognitive rehabilitation works with an occupational therapist and a relative or friend on everyday goals, such as learning to use a phone. Reminiscence and life story work, using photos, keepsakes or music to talk about the past, can improve mood and wellbeing.

If distressing behaviour changes such as agitation, aggression or hallucinations don't respond to these approaches, antipsychotic medicines may be considered for a short time and under close supervision. These are only used when there's a risk of harm to the person or others, and other treatments haven't helped.

When should I see a doctor?

See a GP if you're becoming increasingly forgetful, especially if you're over 65, or if memory problems or other changes in thinking are affecting your daily life or worrying you or someone close to you. If you're concerned about a friend or relative, encourage them to see a GP and consider going along with them.

Don't put off seeking help. One survey found that 1 in 4 people wait two years before raising dementia symptoms with a doctor, but getting help earlier gives you the best chance of accessing treatment and support, and more time to plan ahead.