Experiencing distressing dreams in childhood may be associated with an increased risk for cognitive impairment and Parkinson disease (PD) during adulthood, according to study findings published in the journal eClinicalMedicine.
Several recent studies have shown that the occurrence of frequent bad dreams and nightmares among adults may be an early sign or a potentially modifiable risk factor for the development of both PD and dementia — with the latter known as a type of cognitive impairment. Evidence also suggests that experiencing regular distressing dreams in the middle adult years may be linked to an elevated risk for PD or cognitive impairment a few decades later.
In the current analysis, a researcher sought to explore whether having distressing dreams during childhood can be linked to the risk for PD or cognitive impairment by age 50. For the longitudinal analysis, the researcher utilized 50 years of prospectively obtained data from the 1958 British Birth Cohort Study to investigate the possible link. The British Birth Cohort Study is a prospective birth cohort that comprised all individuals who had been born in Great Britain during a single week in 1958.
The base study population comprised 11,721 individuals who were enrolled at birth in 1958, and had information available on distressing dreams in 1965 (at age 7) and in 1969 (at age 11). Following numerous study exclusions, the final analytical sample included a total of 6991 children with follow-up available at age 50.
All of the data gathered on the children’s distressing dreams were collected prospectively from their mothers in 1965, then again in 1969. The mothers were requested to report whether their child had experienced “bad dreams or night terrors” in the prior 3 months by providing a “yes” or a “no” response. The participants were divided into 3 groups, according to the presence or lack thereof of distressing dreams at ages 7 and 11:
- At no time point
- At 1 time point (at 7 years or 11 years of age)
- At 2 time points (at both 7 years and 11 years of age)
A battery of 3 cognitive tests was administered by trained interviewers when the participants were age 50:
- A 10-item word recall test (evaluates verbal episodic memory)
- The Animal Naming Test (evaluates verbal fluency)
- The Letter Cancellation test (evaluates processing speed)
For the 3 tests, higher scores denote better cognitive performance. “Incident cognitive impairment was defined as scoring ≥2 SD [standard deviations] below the population mean on ≥1 test.” Further, “Incident PD was defined as doctor-diagnosed PD at age 50.”
Of the 6,991 children evaluated, 50.6% were female and 0.7% were non-White. Among the study participants:
- 78.2% reported never having experienced distressing dreams (ie, at no time point);
- 17.9% reported experiencing transient, distressing dreams (ie, at 1 time point); and
- 3.8% reported experiencing persistent distressing dreams (ie, at 2 time points).
At age 50, 3.8% (267 of 6991) of the participants had developed either cognitive impairment (262 individuals) or PD (5 individuals).
According to the fully adjusted model, experiencing more regular distressing dreams in childhood was statistically significantly and linearly associated with a higher risk for cognitive impairment or PD (P for trend =.037). Children who had experienced persistent distressing dreams were 85% more likely than those who never experienced distressing dreams to develop PD or cognitive impairment by age 50 (adjusted odds ratio [aOR], 1.85; 95% CI, 1.10-3.11; P =.019).
A study limitation included the children’s status of distressing dreams was established by maternal report, rather than by self-report, which can potentially lead to an underestimation of the actual prevalence of distressing dreams.
The researcher concluded, “If these findings are replicated in future studies, and the association is confirmed to be causal, it is possible that early treatment of distressing dreams could become a primary prevention strategy for dementia and PD.”
Otaiku AI. Distressing dreams in childhood and risk of cognitive impairment or Parkinson’s disease in adulthood: a national birth cohort study. eClinicalMedicine. Published online February 26, 2023. doi:10.1016/j.eclinm.2023.101872