What nightmares could tell you about your dementia risk

Nightmares in middle age may be a warning sign of dementia, according to a new study.

Weekly bad dreams have been found to quadruple the risk of a middle-aged person suffering from premature cognitive decline, while those who have bad dreams less than once a week are twice as likely to suffer cognitive decline than those who never have nightmares.

Cognitive decline is a well known warning sign of dementia, as it is when the brain begins to struggle against the disease’s suffocating proteins which choke neurons.

Researchers from the University of Birmingham found that bad dreams could become more common several years or even decades before the telltale hallmarks of dementia - thinking issues and memory problems - set in.

Dr Abidemi Otaiku, study author from the University of Birmingham, said: “We’ve demonstrated for the first time that distressing dreams, or nightmares, can be linked to dementia risk and cognitive decline among healthy adults in the general population.

“This is important because there are very few risk indicators for dementia that can be identified as early as middle age.

“While more work needs to be done to confirm these links, we believe bad dreams could be a useful way to identify individuals at high risk of developing dementia, and put in place strategies to slow down the onset of disease.”

For the study, published in The Lancet journal eClinicalMedicine, Dr Otaiku examined data from three community-based groups of people in the US.

These included more than 600 middle-aged adult men and women, defined as being between 35 and 64, and 2,600 adults aged 79 and older.

All the people were dementia-free at the start of the study and were followed up for an average of nine years for the younger group and five years for the older group.

They were asked questions about the quality of their sleep, including how often they experienced bad dreams. The findings showed that middle-aged people were four times more likely to suffer cognitive decline over the following decade, while older people were twice as likely to be diagnosed with dementia if they had weekly nightmares.

These findings appeared to be much stronger for men than for women. For example, older men experiencing nightmares on a weekly basis were five times more likely to develop dementia than older men reporting no bad dreams. In women, however, the increase in risk was only 41 per cent.

Dr Otaiku said more research was needed to examine the findings, including investigating whether nightmares among young people could be associated with future dementia risk.

Dr Otaiku's working hypothesis is that damage to the brain's right frontal lobe, caused by neurodegeneration, may be to blame for the link between nightmares and dementia, The Guardian reports.

How often people remember dreams and how vivid they are could also provide clues to dementia risk.