October 19, 2022
Middle aged men and women who have troubling dreams at least once a week are at increased risk of cognitive decline years down the road, a new report suggests. Frequent nightmares in seniors may also signal an increased risk of dementia, the study found.
The findings add to growing evidence showing links between sleep troubles and an increased risk of Alzheimer’s disease. Alzheimer’s remains the most common form of dementia worldwide. If the findings are confirmed, the presence of scary dreams could potentially serve as an early warning sign of later memory problems, allowing people to adopt lifestyle measures, such as eating a healthy diet and getting regular exercise, to help lower their risk.
“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,” said study author Dr. Abidemi Otaiku, of the University of Birmingham’s Centre for Human Brain Health in Britain. “This is important because there are very few risk indicators for dementia that can be identified as early as middle age.”
For the study, in the journal eClinicalMedicine, Dr. Otaiku analyzed medical data from two groups of Americans. Participants completed detailed questionnaires about their sleep habits, including the frequency of nightmares, which the authors defined as bad dreams that cause distress and trouble sleeping. None had Alzheimer’s disease or other forms of dementia at the start of the study.
The first group included 605 men and women aged 35 to 64 who were followed for an average of nine years. Those who had nightmares on a weekly basis were four times more likely, overall, to develop significant declines in memory and thinking skills compared to their peers who did not have distressing dreams. Faster cognitive decline with aging may be an early warning sign of future dementia.
The second group consisted of 2,600 men and women in their 80s and older who were followed for five years. Those who regularly had nightmares were twice as likely to develop dementia, the researchers found.
The findings build on earlier research showing links between scary dreams and troubled sleep and various brain ailments. Recurring dreams with aggressive content that cause a person to thrash in their sleep, for example, may be a harbinger of impending Parkinson’s disease, studies show. Parkinson’s may also lead to cognitive decline and dementia.
Nightmares may also cause people to awaken during sleep, impairing sleep quality. And numerous studies have shown links between troubled sleep, including insomnia and sleep apnea, and increased Alzheimer’s risk. Other studies have shown that men and women who slept less than six hours a night in their 50s and 60s were at increased risk of developing dementia when they were older.
Sleep problems generally increase with advancing age and, as these and other studies show, may be priming the brain for dementia. Depression and anxiety are likewise linked to an increased risk of Alzheimer’s disease, and nightmares may be a nighttime manifestation of a troubled mental state.
More research needs to be done to confirm the possible links between bad dreams and dementia. Around 5 percent of adults experience nightmares on a weekly basis, and more than 12 percent have a nightmare at least monthly, the authors report. Not all of these people will go on to develop dementia.
But it is possible that frequent nightmares could be one more factor that helps to identify those at increased risk for Alzheimer’s. In people at high risk, prevention strategies — including eating a heart-healthy diet, regular exercise, not smoking and avoiding excessive alcohol — may help to curb or delay the onset of the disease. Scientists believe that such strategies, along with potential new treatments, may be most effective if they are implemented at the earliest stages of the disease, long before memory loss and thinking problems become evident.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Abidemi I. Otaiku: “Distressing Dreams, Cognitive Decline, and Risk of Dementia: A Prospective Study of Three Population-Based Cohorts.” Lancet: eClinicalMedicine, Sept. 21, 2022
