UK study shows interplay between nightmares, cognitive decline, dementia

Having frequent distressing dreams may signal a higher risk of developing cognitive decline and dementia in adults, according to a prospective study of three population-based cohorts.

“[Our study showed that] distressing dreams predict cognitive decline in midlife and all-cause dementia development in late life,” said lead study author Dr Abidemi Otaiku from the UK Dementia Research Institute, Imperial College London in the UK, at EAN 2024.

The risk of cognitive decline was evaluated in 605 middle-aged adults from the Midlife in the United States study. The risk of incident all-cause dementia was evaluated in 2,600 older adults from two studies – the Osteoporotic Fractures in Men Study and the Study of Osteoporotic Fractures. Participants were re-assessed after 5 years (for the outcome of dementia) or 9 years (for the cognitive decline outcome). [EAN 2024, abstract OPR-001]

Ninety middle-aged adults experienced cognitive decline after 9 years. Those who had weekly distressing dreams had a fourfold risk of experiencing cognitive decline compared with those with no distressing dreams at baseline (adjusted odds ratio [aOR], 3.99). Moreover, those who had less-than-weekly distressing dreams had a twofold risk of experiencing cognitive decline 9 years later.

A similar pattern was seen among older adults. Five years later, 235 individuals were diagnosed with dementia of any cause. Those who had weekly distressing dreams had a twofold risk of developing dementia vs those who never had nightmares (aOR, 2.2).

“In both cohorts … the greater the frequency of nightmares, the greater the risk of both outcomes,” said Otaiku. “Therefore, distressing dreams may cause, or could be a very early sign of, dementia.”

Bad dreams need attention, too

“It is estimated that one in three people will develop dementia at some point in their life, particularly as they age,” Otaiku said. To date, about 50 million individuals have dementia. According to Otaiku, this number is expected to triple by 2050.

“Given that there is no cure, it is important that we identify individuals [as early as possible] before they develop symptoms so they can benefit from disease-modifying drugs, when available, and prevention strategies,” he said.

However, he stressed that finding out who will get dementia could be challenging. “[In our study,] we identified nightmares as one of its strongest signs … Nightmares have a very strong link with many brain and other conditions, and I strongly believe that nightmares should be asked about more often by physicians.”

For nightmares triggered by psychological causes, Otaiku recommended approaches targeted at improving stress levels, such as lifestyle modifications, psychotherapy, or medications.

For nightmares that affect quality of life (QoL) even without any discernible cause, he suggested image rehearsal therapy right before bedtime. “Think of a bad dream you regularly have. [Before going] to bed, think about how you can change the ending. For example, if you think you’re being chased and eaten by a tiger, change the end to the tiger giving you a hug. You can even write it down and rehearse that image in your head before you go to bed.”

Nightmares that do impair QoL should drive an individual to schedule that checkup. “Don’t leave your nightmares untreated. [T]alk to your doctor about it,” Otaiku concluded. He called for future trials to ascertain whether treating distressing dreams may help slow cognitive decline and prevent dementia.