A recent study found that children who had persistent nightmares were 76% more likely to develop cognitive impairment and about seven times more likely to develop Parkinson’s disease by the age of 50.

In most cases, bad dreams are not a sign of serious health issues. However, new research has found potentially troubling associations between frequent nightmares and future cognitive functioning [1].

Researchers have found a link between sleep problems in adulthood, including nightmares, and neurodegenerative diseases. Recent studies have found a link between distressing dreams during childhood and cognitive health issues [2].

Based on data collected during a single week in 1958, a prospective, longitudinal analysis was conducted [3]. Parents were asked whether their children had experienced “bad dreams or night terrors” in the previous three months at the ages of seven (in 1965) and 11 (in 1969). 

The percentage of children who never had bad dreams was 78.2%, 17.9% had transient bad dreams and 3.8% had persistent bad dreams. This was among 6991 children, 51% of whom are girls. Among the 262 participants who were 50 years old (2008), five were diagnosed with Parkinson’s disease.

After adjusting for all covariates, having more frequent nightmares throughout childhood was “linearly and statistically significantly” linked to a greater risk of having cognitive impairment or Parkinson’s disease in both men and women. At age 50, those with persistent bad dreams had an 85% raised risk of cognitive impairment or Parkinson’s disease.

In middle-aged and older adults, similar results were found. In a recent large cohort study, healthy middle-aged adults who had nightmares at least once a week were four times more susceptible to experience cognitive decline [4, 5].

Dementia was twice as likely to be diagnosed in older adults with the same frequency of nightmares, as in those without nightmares. The analysis involved 605 middle-aged adults (aged 35-64 years). They were followed for up to 13 years and 2600 older adults (aged ≥ 79 years) followed for up to 7 years. 

After adjusting for all covariates, greater frequency of bad dreams was positively associated with a higher risk for cognitive decline in middle-aged adults and a higher risk for dementia in older individuals. In the fully adjusted model, those who mentioned having one or more bad dreams weekly had a fourfold risk for cognitive decline.

This was comparing them with those who had none. Older adults who had one or more bad dreams weekly had a greater than twofold higher risk for dementia.

For those with clinically diagnosed nightmare disorder, a new study suggests that listening to positive sounds while sleeping may be a significant intervention [6]. 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.

A nightmare was recalled, mentally changed into something positive, and then practiced during a day. A specific sound was also played to half of the participants while they practiced positive dreams. 

During their REM cycles, the sound was played for two weeks. Hearing the sound significantly reduced nightmares in those who heard it. 

The authors reported that this difference was sustained at three-month follow-up and displayed a medium to large effect size. Even though occasional distressing dreams are likely to be safe, concerns about health implications associated with frequent nightmares and the interventions needed to stop them have driven interest in this week’s top clinical topic.

Are you interested to know more? Here’s a quiz on sleep and dementia risk.

[1] https://reference.medscape.com/viewarticle/989572?reg=1
[2] https://www.medscape.com/viewarticle/989142
[3] https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(23)00049-4/fulltext
[4] https://www.medscape.com/viewarticle/981468
[5] https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(22)00370-4/fulltext
[6] https://www.medscape.com/viewarticle/983311