This Common Problem May Actually Be an Early Sign of Dementia, According to Neuroscientists

While the most well-known early signs of dementia include forgetfulness, confusion, and clumsiness, some are so inconspicuous they happen in your literal sleep.

Fortunately—or perhaps unfortunately for those experiencing them—this particular symptom is hard to ignore (and may keep you up at night): According to research from University of Birmingham in the U.K., recurring nightmares may be an early warning sign of dementia.

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What Did the New Dementia Study Find?

Published in The Lancet's eClinicalMedicine and conducted by Dr. Abidemi Otaiku, a medical doctor and neuroscientist at Imperial College London, the study analyzed data from three large American health and aging studies.

The study included a total of 3,205 dementia-free adults, 605 of whom were middle aged (between the ages of 35 and 64), and followed them for an average of 10 years. The remaining 2,600 were "older" (79 and above) and followed for an average of five years. Every participant, regardless of age, also completed a questionnaire regarding how often they had bad dreams or nightmares.

Related: This Subtle TV Habit Could Be an Early Sign of Dementia

Nightmares are associated with cognitive decline and increased dementia risk.

After tracking each patients' cognitive decline and whether they were diagnosed with dementia, Dr. Otaiku found that middle-aged adults (ages 35 to 64) who had nightmares at least once a week were four times more likely to experience cognitive decline in the following decade.

Similarly, older adults (ages 79+) who had weekly nightmares were twice as likely to develop dementia than participants without them.

Related: Following This Type of Eating Plan Could Lower Dementia Risk—and It's Not the Mediterranean Diet

Men who reported frequent nightmares were at a higher risk of dementia than women.

Also of note? Men seem to be at a much higher risk than women: Older men with weekly nightmares were five times more likely to develop dementia while women's risk only increased by 41%.

Related: The Best Sleep Position for Preventing Cognitive Decline

What Does This Mean for Me?

This research could be groundbreaking for dementia research and treatment, since weekly nightmares could serve as an early warning sign years or even decades before real dementia symptoms set in. This is especially impactful since nightmares are so common: 85% of adults have at least one nightmare a year, 8% to 29% of adults have them monthly, and 2% to 6% report weekly nightmares.

That might seem scary, but it's ultimately a good thing. As Dr. Otaiku wrote in a follow-up story, these findings may "help shed light on the relationship between dementia and dreaming, and provide new opportunities for earlier diagnoses–and possibly earlier interventions."

It also confirms the critical connection between sleep and brain health. Previous research had already linked poor sleep in middle age to Alzheimer's disease, and now we understand how nightmares factor into the equation. With this knowledge, individuals can proactively address sleep issues, knowing that improving sleep health and hygiene may help prevent—or at least slow—cognitive decline in the future.

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Related: Doing This for Just 5 Minutes a Day Can Lower Your Dementia Risk by 41%

Sources

• "Distressing dreams, cognitive decline, and risk of dementia: A prospective study of three population-based cohorts." The Lancet's eClinicalMedicine

• Dr. Abidemi Otaiku

• "An Early Sign of Dementia Risk May Be Keeping You Up at Night." ScienceAlert.

• "Correlates and Treatments of Nightmares in Adults." Sleep Medicine Clinics.

• "Lack of sleep in middle age may increase dementia risk." National Institutes of Health.