Every night, like clockwork, many of us set our alarm, and fall into a deep slumber until the next morning. In between the time we fall asleep and wake up, some of us experience a series of nightmares, from our plane crashing down to being buried alive. Nightmares in adults can be a subconscious reaction to everyday stressors, but researchers at the University of Turku suggest they could predict the onset of several health conditions.

"Frequent nightmares have been linked to other sleep problems, especially insomnia, and mental health problems, especially symptoms of depression, as well as to lowered quality of life in general," wrote the researchers in the study’s abstract, published in Scientific Reports.

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Specifically, researchers found can nightmares can elevate the risk of suicide among both the general population and World War II veterans. Previous research has found nightmares serve as a strong predictor of suicide among men who were WWII veterans, but they were not identified and analyzed separately from the general population. Therefore, this prompted the researchers to identify war veterans, and investigate whether war experiences were more of a predictor of suicide than nightmare frequency, and then compare risk factors for these dreams with the general population.

Over 70,000 (about 3,000 were veterans) male and female participants between 25 and 74 years were examined using data from the Finnish National FINRISK Study, a set of surveys conducted every five years from 1972 to 2012. This ensured the sample size was larger with an extended follow-up period, and more statistical data was available to compare and contrast. This data was linked to the Causes of Death Registry, and participants followed the rules of their experiment until the end of 2014, or death.

The FINRISK surveys included a variety of questions, such as: “Did you serve on the front during the last wars? Yes/no,” and a follow-up question, “Were you wounded during the war,” with answer options “no”, “yes, slightly (no permanent injury)” and “yes, I am a war invalid.”

Questions like, “During the past 30 days have you had nightmares? ” with answer options “often”, “sometimes” and “never” were used to determine nightmare frequency.

Symptoms of insomnia were measured by asking: “During the past 30 days have you had insomnia? ” with answer options “often”, “sometimes” and “never.”

Meanwhile, between 1972 to 2012, they also conducted surveys on depression symptoms and alcohol use.

Zombie The frequency of nightmares can predict the onset of these three health problems, including suicide risk. Photo courtesy of Pixabay, Public Domain

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Dreams, good and bad, occur during rapid eye movement (REM) sleep. This stage of sleep helps us process what we experience every day, and make sense of it. However, disruptive REM sleep leads to the inability to process our emotional state, and therefore, bothers the brain. This is when nightmares begin to happen during sleep.

The prevalence of frequent nightmares among the whole sample, including war veterans was 3.4 percent of men and 4.8 percent of women. The occurrence of nightmares among war veterans was statistically significant at 7.6 percent. However, during the follow-up period, there were a total of 398 suicides; 32 suicides were comprised of war veterans. Overall, nightmares did appear to slightly increase suicide risk among both populations, but among war veterans, the link between nightmares and suicide risk was not stronger.

Nils Sandman, corresponding author of the study, told PsyPost: "People who experience frequent nightmares may also be susceptible to mood disorders and they have slightly higher risk for committing suicide than people without nightmare problem(s)."

Sandman and his colleagues do admit there were several limitations in their study. The researchers were not able to gather information about the exact details of veterans' nightmares, which means they can't tell whether they were war related. Moreover, the researchers were not able to gather other information about post-traumatic symptoms among veterans.

"There is mounting evidence that nightmares are related to many problems of well-being. In the future they should receive more clinical attention as they might have value as an early warning sign of more serious problems,” said Sandman.

Scientific literature has found nightmares are associated with serious health conditions. In regards to mental health, a 2014 study found children who suffer from frequent nightmares or night terrors may face an increased risk of psychotic experiences in adolescence. Victims of bullying and nightmares indicate that experiences during the day are still processed at night, and this causes a change in stress responses physiologically. Both of these have been related to increased risk of developing mental health problems.

When it comes to heart health, nightmares can wreak havoc. A 2003 study found an increase in nightmares among elderly men and women was linked to an increase in heart disease. These participants experienced irregular heartbeats and spasmodic chest pain.

Nightmares are more than just bad dreams — they surface our fears and stresses, which can negatively impact our health if not resolved.

Source: Sandman N, Valli K, Kronholm E et al. Nightmares as predictors of suicide: an extension study including war veterans. Scientific Reports. 2017.

See Also:

The 10 Most Common Nightmares And What They Say About Your Life

5 Most Common Stress Dreams And What Psychologists Say They Mean