You may already know that poor sleep, especially in midlife, has been linked to increased dementia risk later down the line.
But according to a 2022 study, what you dream about during those crucial hours may also be linked to your likelihood of developing the condition ― especially for man.
The paper, published in medical journal The Lancet’s eClinical Medicine, found that middle-aged participants who had nightmares at least once a week were four times more likely to experience cognitive decline (a precursor to dementia) over the following decade than those who did not.
The study’s lead author Dr. Abidemi Otaiku recently wrote for Science Alert: “These results suggest frequent nightmares may be one of the earliest signs of dementia, which can precede the development of memory and thinking problems by several years or even decades – especially in men.”
How did the study work and what did it find?
The researchers looked at data from large US studies, one of which involved 605 adults aged between 35 and 64, and another which involved 2,600 participants aged over 79.
The studies followed the younger group for about nine years and the older group for an average of five years. None of the participants had dementia at the start of the studies.
All participants were asked to fill in questionnaires at the start of the study, including one which asked how often they had bad dreams and nightmares that wake them up in the middle of the night.
“I found that middle-aged participants who experienced nightmares every week, were four times more likely to experience cognitive decline over the following decade, while the older participants were twice as likely to be diagnosed with dementia,” Dr Otaiku wrote for Science Alert.
Men in the older age bracket who got woken up by nightmares at least once a week were five times more likely to develop cognitive decline than those who didn’t.
For older women, the risk was 41% higher, while middle-aged groups saw similar patterns.
Does that mean I’m definitely going to get dementia if I have nightmares once a week?
No. That’s not what the paper says ― it only found an association, not a cause.
“These results suggest frequent nightmares may be one of the earliest signs of dementia, which can precede the development of memory and thinking problems by several years or even decades – especially in men,” Dr Otaiku wrote for Science Alert; but he added his 2022 data couldn’t prove that, and didn’t seek to.
“The good news is that recurring nightmares are treatable,” he later told the publication, linking to a paper that suggested using different forms of therapy and medications for those with recurring nightmares depending on their cause.
“And the first-line medical treatment for nightmares has already been shown to decrease the build-up of abnormal proteins linked to Alzheimer’s disease.”