What is dementia
Dementia is an umbrella term used to describe a group of symptoms caused by diseases that damage the brain. According to the NHS, dementia affects memory, thinking, language, behaviour and the ability to carry out everyday activities. It is not a single disease in itself, and it is not a normal part of ageing, although age is the strongest risk factor.
Dementia develops when brain cells are damaged and can no longer communicate effectively. Over time, this damage interferes with cognitive functioning and daily life. The progression is usually gradual, though the pattern of decline varies depending on the underlying cause. Some forms worsen steadily, while others progress in steps, particularly when strokes are involved.
The World Health Organization estimates that over 55 million people worldwide are living with dementia, with nearly 10 million new cases diagnosed each year. In the UK, the NHS recognises dementia as a major public health challenge due to its impact not only on individuals but also on families, carers and health services.
Common symptoms of dementia
Memory loss is often the first symptom people notice, but dementia involves more than forgetting names or misplacing keys. Early signs may include difficulty planning or organising tasks, struggling to follow conversations, problems finding the right words, and confusion in familiar environments.
Changes in mood and personality are also common. A person may become withdrawn, anxious, irritable or unusually apathetic. Judgement may decline, which can affect financial decisions or safety awareness. The key distinction is whether these changes begin to interfere with everyday functioning. Occasional forgetfulness is common with ageing. Persistent cognitive decline that disrupts daily life requires medical assessment.
The NHS advises that anyone concerned about symptoms should book a GP appointment. Early assessment can rule out other causes such as depression, vitamin deficiencies, thyroid problems or medication effects. It can also allow earlier access to support and planning.
The different types of dementia
Dementia has several causes. Understanding the type is important because it shapes the expected pattern of symptoms, management approaches and support planning.
Alzheimer’s disease
Alzheimer’s disease is the most common cause of dementia in the UK. It is associated with abnormal protein deposits in the brain, including amyloid plaques and tau tangles, which disrupt communication between neurons and lead to cell death.
Early symptoms often involve difficulty learning new information and short term memory loss. As the condition progresses, individuals may experience disorientation, language difficulties and behavioural changes. Research consistently shows that Alzheimer’s disease follows a progressive neurodegenerative course, although the rate of decline varies between individuals.
Vascular dementia
Vascular dementia is caused by reduced blood flow to the brain. This may result from a stroke or from long term small vessel disease. Damage occurs when brain tissue is deprived of oxygen.
Unlike Alzheimer’s disease, early memory loss may be less prominent. Instead, people may experience slowed thinking, problems with attention, poor planning skills and a stepwise pattern of decline following vascular events. Managing cardiovascular risk factors such as hypertension, diabetes and high cholesterol is central to prevention and ongoing care.
Mixed dementia
Mixed dementia refers to the presence of more than one underlying pathology. The most common combination is Alzheimer’s disease with vascular changes. Symptoms often reflect a blend of both patterns. Research suggests that mixed pathology is common in older adults, particularly in advanced age.
Dementia with Lewy bodies
Dementia with Lewy bodies is characterised by abnormal deposits of alpha synuclein protein in the brain. It presents differently from Alzheimer’s disease.
Individuals often experience fluctuating alertness and cognition, detailed visual hallucinations and movement symptoms similar to Parkinson’s disease. Sleep disturbances are also common. This type of dementia can be particularly challenging to diagnose due to its overlapping features with other neurological conditions.
Frontotemporal dementia
Frontotemporal dementia tends to occur at a younger age compared to other forms, often between 45 and 65 years. It primarily affects the frontal and temporal lobes of the brain.
Early symptoms often involve marked personality or behavioural change. A person may become socially inappropriate, impulsive or emotionally blunted. In other cases, language impairment is the dominant feature. Memory can appear relatively preserved in early stages, which may delay recognition.
Why early assessment matters
There is currently no cure for most forms of dementia, but diagnosis still matters. Early identification allows individuals and families to understand what is happening, access support services and make informed decisions about care, finances and future planning.
NICE guidelines recommend a structured assessment process, including cognitive testing, medical history, physical examination and, where appropriate, brain imaging. Multidisciplinary memory services play a central role in diagnosis and management across the NHS.
Research from large scale reviews, including the Lancet Commission on dementia prevention and care, highlights that while some risk factors are non modifiable, others such as hypertension, hearing loss, smoking, physical inactivity and social isolation can be addressed across the lifespan. Prevention strategies therefore form part of a broader public health response.
Final reflection
Dementia is complex. It is not simply about memory loss. It affects identity, relationships and independence. Families often delay seeking help because they are unsure whether changes are significant. The NHS guidance is clear. If cognitive or behavioural changes are affecting daily life, speak to a GP.
Early action does not remove the diagnosis, but it improves clarity, safety and access to support.
Reference List
Livingston, G., Huntley, J., Sommerlad, A., Ames, D., Ballard, C., Banerjee, S., Brayne, C., Burns, A., Cohen Mansfield, J., Cooper, C., Costafreda, S. G., Dias, A., Fox, N., Gitlin, L. N., Howard, R., Kales, H. C., Kivimäki, M., Larson, E. B., Ogunniyi, A., … Mukadam, N. (2020). Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet, 396(10248), 413–446. https://doi.org/10.1016/S0140-6736(20)30367-6
National Health Service. (2023a). Dementia overview. https://www.nhs.uk/conditions/dementia/
National Health Service. (2023b). Symptoms of dementia. https://www.nhs.uk/conditions/dementia/symptoms-and-diagnosis/symptoms/
National Health Service. (2023c). Causes of dementia. https://www.nhs.uk/conditions/dementia/about-dementia/causes/
National Health Service. (2023d). Vascular dementia. https://www.nhs.uk/conditions/vascular-dementia/
National Health Service. (2023e). Dementia with Lewy bodies. https://www.nhs.uk/conditions/dementia-with-lewy-bodies/
National Health Service. (2023f). Frontotemporal dementia. https://www.nhs.uk/conditions/frontotemporal-dementia/
National Institute for Health and Care Excellence. (2018). Dementia: Assessment, management and support for people living with dementia and their carers (NICE Guideline NG97). https://www.nice.org.uk/guidance/ng97
World Health Organization. (2023). Dementia fact sheet. https://www.who.int/news-room/fact-sheets/detail/dementia