Sudden change of humour could signal dementia - study

John Cleese as the Minister of Silly Walk from Monty Python's Flying Circus. Photo / File

Developing a sudden liking for slapstick comedy such as Mr Bean or The Benny Hill Show, could herald the onset of dementia up to nine years before the illness is diagnosed.

According to University College London (UCL), a change in sense of humour can provide a "red flag" to family members and doctors, giving an early warning sign that neurodegenerative disease has begun.

Many family members notice behavioural and personality changes in their loved ones in the years before dementia is diagnosed, and researchers speculated that humour may be one of the most obvious alterations.

Friends or relations of 48 people with different forms of frontotemporal dementia and Alzheimer's Disease were asked to rate their preference for different kinds of comedy and how it had changed over 15 years. The researchers found that people with both types of dementia preferred slapstick humour to more cerebral satirical comedy, such as Yes Minister, or absurdist comedy, such as that of Monty Python and The Goon Show, even if they had previously been fans of more complex comedy.

People with frontotemporal dementia also appeared to develop a darker sense of humour, taking delight in other people's misfortunes. And when they made jokes they tended to be graphic, smutty or childish in their subject, according to the study. Many stopped laughing altogether. The same was not true of Alzheimer's sufferers.

While Alzheimer's disease is the leading cause of dementia, frontotemporal dementia is the most common cause of dementia in the under-55s.

Friends and relations reported seeing the changes in sense of humour for both forms of dementia an average of at least nine years before the start of more typical dementia symptoms such as memory loss.

Dr Camilla Clark who led the research at the Dementia Research Centre, UCL, said: "As sense of humour defines us and is used to build relationships with those around us, changes in what we find funny has impacts far beyond picking a new favourite television show.

"These findings have implications for diagnosis - personality and behaviour changes should be prompts for further investigation, and clinicians themselves need to be more aware of these symptoms as a potential early sign of dementia.

"As well as providing clues to underlying brain changes, subtle differences in what we find funny could help differentiate between the different diseases that cause dementia.

"Humour could be a particularly sensitive way of detecting dementia because it puts demands on so many different aspects of brain function, such as puzzle solving, emotion and social awareness."

The study was published in the Journal of Alzheimer's Disease.