A new study found that people who had bad dreams at least once a week were four times more prone to cognitive decline.
People who experience frequent nightmares in middle age may have a faster rate of cognitive decline and be at greater risk of dementia as they age, data suggests.
If confirmed, the research could eventually lead to new ways to detect dementia and intervene to slow the rate of decline.
Most people have nightmares from time to time, but about 5 percent of adults have nightmares—dreams painful enough to wake them up—at least once a week.
Stress, anxiety and sleep deprivation are all potential triggers, but previous research in people with Parkinson’s has also linked frequent stressful dreams to a faster rate of cognitive decline, as well as an increased risk of develop dementia in the future.
New ways to detect dementia
To investigate whether the same might be true of healthy adults, Dr Abidemi Otaiku from the University of Birmingham turned to data from three previous studies that examined people’s sleep quality and then followed them over several years , assessing their brain health as well as other outcomes.
This included more than 600 middle-aged adults (aged 35 to 64) and 2,600 people aged 79 and over. Their data was analyzed using statistical software to find out whether those who had a higher frequency of stressful dreams were more likely to experience cognitive decline and be diagnosed with dementia.
The research, published in eClinicalMedicinefound that middle-aged people who had nightmares at least once a week were four times more likely to experience cognitive decline over the next decade than those who rarely had nightmares.
Among the elderly participants, those who reported frequent nightmares were twice as likely to be diagnosed with dementia in later years.
People who have frequent nightmares have poor quality sleep
One possibility is that people who have frequent nightmares have poor quality sleep, which could gradually lead to a build-up of proteins associated with dementia, he writes The Guardian.
Another possibility is the existence of a genetic factor underlying both phenomena. However, Otaiku’s working hypothesis is that neurodegeneration in the right frontal lobe of the brain makes it harder for people to control their emotions while dreaming, which in turn leads to nightmares.
“We know that neurodegenerative conditions such as Parkinson’s and Alzheimer’s often start many years before someone is diagnosed. In some people who already have an underlying illness, bad dreams and nightmares may be one of the first signs.”
He pointed out that only a subset of adults who regularly have nightmares are likely to develop dementia. However, assuming this link is confirmed, nightmares could eventually be used to identify high-risk individuals.