(NewsNation) — People who experienced frequent nightmares in childhood may be at an increased risk of developing cognitive impairment, such as dementia, and Parkinson’s disease, according to a new study.

The research, published Sunday in The Lancet’s eClinicialMedicine journal, analyzed data from the 1958 National Child Development Study, an ongoing survey that has been gathering information from more than 17,000 people born across England, Wales and Scotland during a single week in March 1958.

The study surveys the cohort at various stages of life, including ages 7 and 11, at which time their mothers were asked whether their child had experienced “bad dreams or night terrors” in the previous three months. No definition for those terms was given.

At age 50, study participants were administered a battery of tests to determine cognitive abilities.

Children who experienced persistent distressing dreams were 76% more likely to develop cognitive impairment than those who did not, author Abidemi Otaiku wrote in his findings.

“These results suggest that having regular bad dreams and nightmares during childhood may increase the risk of developing progressive brain diseases like dementia or Parkinson’s disease later in life,” Otaiku, a fellow at the University of Birmingham, wrote in an article. “They also raise the intriguing possibility that reducing bad dream frequency during early life could be an early opportunity to prevent both conditions.”

He noted further studies would be needed to confirm the link between nightmares and the medical conditions.

The data analysis found that of 268 children who reported persistent nightmares — defined as having nightmares at both age 7 and 11 — 17, or 6.3% of that group, developed cognitive impairments. Comparatively, only 3.6% of children who were reported as never having experienced nightmares developed cognitive impairments.

Otaiku offered three possible connections for the association.

First, it’s possible the bad dreams are an “early manifestation” of neurodegenerative diseases such as dementia, Parkinson’s or Alzheimer’s disease.

“This hypothesis would be consistent with a recent study which demonstrated that the frequency of
distressing dreams in adults with PD was positively correlated with atrophy of grey and white matter in their right frontal (brain) lobes,” Otaiku wrote in his findings.

Second, there are genetic factors that could predispose people to distressing dreams and cognitive impairment. A gene known to increase nightmares has also been linked to an increased risk of Alzheimer’s, according to Otaiku.

Finally, Otaiku says the frequent bad dreams could possibly be causal risk factors for cognitive impairment.

“For example, distressing dreams are known to cause disturbed sleep … which could in turn lead to impaired glymphatic clearance during sleep, and thus greater accumulation of pathological proteins in the brain,” he writes.

If causation is proved by future studies, Otaiku posits early treatment of nightmares could be a “primary prevention strategy” for dementia and Parkinson’s disease.