Middle-aged adults who experience frequent nightmares may have an increased risk of dementia later in life, a new study suggests.
The study published in The Lancet journal on Wednesday suggests people who are diagnosed with dementia in their later years of life show a cognitive decline years in advance with signs like distressing dreams.
Researchers at the University of Birmingham in the UK analyzed data from three separate cohort US studies that followed 605 men and women aged 35-64 and 2,600 adults aged 79 and older. The data followed all participants for an average of nine years and all of them were dementia-free at the beginning of the study.
Participants were asked to complete the Pittsburgh Sleep Quality Index questionnaire, which assesses a person’s sleeping patterns and quality of sleep. The questionnaire covers a variety of sleep factors including sleep duration, use of sleep medication, daytime dysfunction and sleep disturbances.
From the data collected, the researchers found that middle-aged participants who experienced nightmares on a weekly basis were four times more likely to experience cognitive decline over the next decade in comparison to those who didn’t experience nightmares. Among those aged 79 and older, participants who experienced weekly bad dreams were twice as likely to be diagnosed with dementia.
“This is important because there are very few risk indicators for dementia that can be identified as early as middle age,” lead researcher Dr. Abidemi Otaiku said in a press release.
According to the Alzheimer Society of Canada, sleep disturbances are extremely common for people with dementia. Their sleeping issues can range from insomnia, frequent naps throughout the day, to sleeping all day and staying awake all night. This can often lead to “sundowning,” which is when a person with dementia experiences heightened confusion or aggression in the late afternoon or early evening.
The study authors hypothesize the relation between nightmares and cognitive decline may be linked to neurodegeneration. This progressive damage to nerve cells, specifically in this case, attacks the right frontal part of the brain which is supposed to suppress negative emotions during conscious states like dreaming. The researchers hypothesize this since most of the participants who experienced nightmares were more likely to be more depressed or anxious.
The researchers say they aim to further investigate other factors of dreaming patterns that can be linked to dementia, including the frequency of dreaming or how vivid dreams can be.
“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 said in the press release.