Nightmares in middle age linked to higher dementia risk years later

BIRMINGHAM, United Kingdom — The occasional nightmare is something most people have from time to time, but researchers from the University of Birmingham have found that experiencing bad dreams frequently during middle age could be a sign of future cognitive decline and dementia onset years or decades later.

“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,” says Dr. Abidemi Otaiku, of the University of Birmingham’s Centre for Human Brain Health, in a media release.

“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,” Otaiku adds.

The researchers included three U.S. community-based samples in the study, encompassing over 600 men and women between the ages of 35 and 64, as well as another 2,600 adults 79 or older. Each person did not have dementia at the start of the study. Study authors tracked the younger group for an average of nine years, while following the older group for five years. This data collection took place between 2002 and 2012.

Meanwhile, each adult also filled out a series of questionnaires, such as the Pittsburgh Sleep Quality Index, which featured a question specifically asking about bad dream frequency. The team then analyzed all collected data using statistical software in an effort to determine if those experiencing more nightmares were also more likely to eventually develop cognitive decline and dementia.

Nightmares much more harmful for men

Study authors report middle-aged individuals (ages 35-64) dealing with nightmares on a weekly basis are four times more likely to experience cognitive decline over the following decade. Older adults were also twice as likely to receive a dementia diagnosis.

Notably, these connections were much stronger among men than women. Older men having nightmares every week were five times more at risk of dementia than older men reporting no bad dreams. The same scenario among women, however, only resulted in a 41-percent higher risk.

Moving forward, study authors would like to see more research on this topic. More specifically, what impact do nightmares have on young people and adolescents? There's also the matter of more specific dream characteristics. The vividness and recollection of dreams may also help identify dementia risk.

Using electroencephalography (EEG) and magnetic resonance imaging (MRI), the research team is already planning on performing further investigations looking at the biological basis of bad dreams among both healthy people and people diagnosed with dementia.

The study is published in the journal EClinicalMedicine.