Adults who report having nightmares during middle and older age may experience accelerated cognitive decline and are at increased risk of developing dementia, according to new research from the University of Birmingham.
Abidemi Otaiku suggests nightmares may become prevalent several years or even decades before the characteristic memory and thinking problems of dementia set in. Image credit: Bingo Naranjo.
Nightmares (distressing dreams) are common in the general population.
Approximately 5% of adults experience nightmares weekly, with a further 12-40% experiencing them monthly.
These percentages are likely even higher when considering bad dreams alongside nightmares.
Given the ubiquity of bad dreams and nightmares in the adult population, it is surprising that their clinical significance remains largely unknown.
“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, a researcher in the Centre for Human Brain Health at the University of Birmingham and the Department of Neurology at Birmingham City Hospital.
“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.”
In the study, Dr. Otaiku examined data from three community-based cohorts in the United States.
These included more than 600 adult men and women aged between 35 and 64; and 2,600 adults aged 79 and older.
All the participants were dementia-free at the start of the study and followed up for an average of nine years for the younger group and five years for the older participants.
The study started collecting data between 2002 and 2012. Participants completed a range of questionnaires, including the Pittsburgh Sleep Quality Index, which includes a question on how often individuals experienced bad dreams.
These data were analyzed using statistical software to find out whether participants with a higher frequency of nightmares were more likely to go on to experience cognitive decline and be diagnosed with dementia.
Dr. Otaiku found that middle-aged people (35-64 years old) who experience bad dreams on a weekly basis are four times more likely to experience cognitive decline over the following decade, while older people were twice as likely to be diagnosed with dementia.
Interestingly, he found that the associations were 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%.
“The findings may help to identify individuals at risk of dementia and could facilitate early prevention strategies,” Dr. Otaiku said.
The study was published in the journal eClinicalMedicine.
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Abidemi I. Otaiku. Distressing dreams, cognitive decline, and risk of dementia: A prospective study of three population-based cohorts. eClinicalMedicine, published online September 21, 2022; doi: 10.1016/j.eclinm.2022.101640
