Dementia is a collective term for a range of symptoms associated with progressive conditions that affect memory, thinking and the ability to perform daily activities.^1-4

Alzheimer’s disease is the most common cause of dementia, with other common types being vascular, frontotemporal, and dementia with Lewy bodies – the ‘Big Four’. However, dementia is associated with or caused by many other conditions with more than 200 recognised subtypes. It is also possible to have more than one type of dementia. For example, mixed dementia is most commonly Alzheimer’s with vascular dementia or with Lewy body type dementia.^2,3,5

Globally, 55 million people have dementia and this figure could treble by 2050. In the UK, upwards of 850,000 people are living with dementia with predictions for the number to be 1 million by 2025 and 1.6 million by 2040.^1,2,6

Dementia should not be considered a normal part of the ageing process, but risk does increase with age, so that a third of people aged over 85 have dementia. Under the age of 65, it is described as ‘young onset dementia’, with more than 40,000 people affected in the UK.^5,6,7

In some cases, it may be difficult to determine whether cognitive impairment is due to dementia or is delirium. While the effect on the mental state may be similar, delirium will develop rapidly over a couple of days and often in someone who is unwell, unlike dementia’s (usually) slow progression.^8,9