Dreams are normal occurrences for everyone and most people report having nightmares occasionally. However, the frequency of your nightmares and how old you are when you experience them can reveal information about your risk for dementia.
Research shows that experiencing frequent disturbing dreams and nightmares – particularly frightening dreams that cause you to wake up – may be associated with a higher risk of cognitive decline and dementia.
A 2023 analysis in the American Journal of Preventive Medicine concluded that sleep disorders should be taken into account when assessing someone at risk for dementia. Previous research has discovered a possible link between disturbing dreams and a higher risk of dementia in people with Parkinson’s disease. And a 2022 study published in The Lancet’s eClinicalMedicine found that some associations may also exist in the general population.
The 2022 study, authored by Dr. Abidemi Otaiku, a clinical researcher at Imperial College London, evaluated 605 middle-aged adults at a cognitively normal baseline for up to 13 years. Researchers also examined 2,600 older adults, with a mean age of 83 years, at a dementia-free baseline for up to seven years.
The data suggested that the group of middle-aged adults who reported a higher frequency of nightmares – classified as once a week or more – were associated with a higher risk of cognitive decline. Similarly, the study in older adults found that more nightmares were linked to a higher risk of “all-cause dementia,” meaning the syndrome can be caused by a number of different diseases.
Middle-aged adults who reported having weekly nightmares were four times more likely to experience cognitive decline compared to those who reported none. Older adults with frequent disturbing dreams were about twice as likely to develop dementia.
The cognitive function of the middle-aged participants was assessed using five cognitive tests. The older participants were assessed for dementia by a doctor.
But there were some limitations of the study, such as the lack of racial diversity among the participants, who were mostly white, and a possible underestimation of the associations between nightmares and dementia among the female participants. The associations in the findings between disturbing dreams and risks of cognitive decline and dementia were only significant in the men evaluated, not in the women.
Furthermore, the questionnaire given to participants did not clearly distinguish between “bad dreams” and “nightmares,” which may have influenced the answers. “Bad dreams” don’t wake you up, while nightmares can wake you from your sleep.
In an article published in The Conversation, Otaiku wrote that the study’s results could lead to two theories: first, that frequent nightmares may be one of the first signs of dementia, especially in men; and second, that regular nightmares themselves can be a cause of dementia.
“Given the nature of this research, it is not possible to be sure which of these theories is correct (although I suspect it is the first),” Otaiku wrote. He added that the research could nevertheless provide new opportunities for earlier diagnoses and “potentially earlier interventions.”
More than 55 million people around the world suffer from dementia. With so many ongoing conversations about sleep health and dementia diagnoses, it’s important to be aware of new information about early detection and things you can do to lower your risk.
How to reduce your risk of dementia
Research has shown that regular exercise and physical activity, staying social, and not smoking are among the ways you can reduce your risk of dementia.
Dr. Zaldy Tan, director of the Memory and Healthy Aging Program at Cedars-Sinai, previously told HuffPost that an important tip for improving brain health is avoiding social isolation.
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“As social beings, the human brain thrives on interacting with others… If this doesn’t happen, our memory and cognition can deteriorate over time,” Tan said. “It is important to stay involved and connected with others.”
Getting enough sleep is also key to reducing your risk. However, that can be a challenge if you are someone who experiences nightmares or bad dreams.
If you find yourself having disruptive dreams or nightmares on a regular basis, talk to your doctor about your symptoms. Routine tests are not done to diagnose nightmare disorder, which is a pattern of repeated frightening dreams that cause significant distress. But your doctor can investigate whether other conditions or factors are contributing to the nightmares.
According to the Sleep Foundation, people can also seek out different types of therapeutic treatments, such as psychotherapy, that can address nightmares.