Bad dreams are common and rarely are a sign of significant health concerns. However, several new studies have found potentially troubling associations between frequent or persistent nightmares and future cognition. These findings, along with recent insights into a potential intervention, have resulted in the top trending clinical topic this week. Previous investigations have found a link between sleep problems in adulthood, including nightmares, and the onset of neurodegenerative diseases. A recent analysis determined a possible association between distressing dreams during childhood and cognitive health concerns (see Infographic).

A prospective, longitudinal analysis used data that included all people born in Britain during a single week in 1958. At age 7 years (in 1965) and 11 years (in 1969), mothers were asked to report whether their child experienced "bad dreams or night terrors" in the past 3 months. Among 6991 children (51% girls), 78.2% never had bad dreams, 17.9% had transient bad dreams, and 3.8% had persistent bad dreams. By age 50 years (2008), 262 participants had developed cognitive impairment, and five were diagnosed with Parkinson's disease.

After adjusting for all covariates, having more regular nightmares during childhood was "linearly and statistically significantly" associated with a higher risk of developing cognitive impairment or Parkinson's disease (P = .037) in both men and women. Compared with those who never had bad dreams, those who had persistent bad dreams had an 85% increased risk for cognitive impairment or Parkinson's disease by age 50 years (adjusted odds ratio [aOR], 1.85; 95% CI, 1.10-3.11; P = .019).

These findings echo similar results in middle-aged and older adults. Results from a recent large cohort study found that healthy middle-aged adults who had nightmares at least once a week were four times more likely to experience cognitive decline over the following decade. Older adults with the same nightmare frequency were twice as likely to be diagnosed with dementia, compared with peers who never had bad dreams. The analysis included 605 middle-aged adults (aged 35-64 years) followed for up to 13 years and 2600 older adults (aged ≥ 79 years) followed for up to 7 years. After adjustment for all covariates, a higher frequency of bad dreams was significantly associated with a higher risk for cognitive decline in middle-aged adults (P = .016) and a higher risk for dementia in older adults (P = .001). In the fully adjusted model, those who reported having one or more bad dreams weekly had a fourfold risk for cognitive decline (aOR, 3.99; 95% CI, 1.07-14.85) compared with those who had none. Older adults who had one or more bad dreams weekly had a greater than twofold increased risk for dementia (aOR, 2.21; 95% CI, 1.35-3.62).

For those with clinically diagnosed nightmare disorder, a new study suggests that listening to positive sounds while sleeping may be a significant intervention. A study conducted in Switzerland included 36 participants in a daytime lesson of imagery rehearsal therapy, which taught them to redirect their nightmares to positive dreams. Participants were taught to recall a nightmare, mentally change it into something positive, and then practice the "rewritten dream" during the day. Half of the participants also had a special sound played while they practiced the positive dreams. For 2 weeks, the sound was played during their REM cycles. Those who heard the sound had significantly fewer nightmares. "This difference displayed a medium to large effect size and was sustainable at the 3-month follow-up," the authors reported.

Although infrequent distressing dreams are likely to be harmless, concerns about health implications associated with frequent nightmares, and interventions needed to stop them, are significant enough to have driven interest in the top clinical topic this week.

Reference: https://reference.medscape.com/viewarticle/989572