Poor Reaction to Stress Predicts Insomnia

Deborah Brauser

July 14, 2014

Individuals who cope with stress by using drugs or alcohol or by engaging in self-distraction vs adopting a head-on approach are at increased risk of developing insomnia, new research shows.

Dr. Vivek Pillai

A study of nearly 3000 participants with no history of insomnia at baseline showed that those who did not deal directly with stressful events were more likely to experience insomnia at 1-year follow-up.

Substance use, self-distraction, and having recurrent thoughts about the stressor, described as cognitive intrusion, were also significant mediators of incident insomnia. In fact, cognitive intrusion "accounted for 69% of the total effect on insomnia," investigators report.

"Quite a bit of this was surprising, especially about self-distraction," lead author Vivek Pillai, PhD, from the Sleep Disorders and Research Center at Henry Ford Hospital in Detroit, Michigan, told Medscape Medical News.

"Psychologists often recommend self-distraction, such as watching TV or going to the movies, to take your mind off of a stressful event. But there's been some debate as to whether or not that's just a short-term alternative to actual coping," he said.

Dr. Pillai added that this is the first study to show that self-distraction actually increases insomnia risk.

The study was published in the July 1 issue of Sleep.

Common Problem

Estimates from the American Academy of Sleep Medicine (AASM) show that 10% to 20% of adults experience insomnia lasting less than 3 months. Insomnia disorder is more prevalent in women than men.

The investigators analyzed data from the Evolution of Pathways to Insomnia Cohort (EPIC) study for 2892 "good sleepers," defined as individuals who have no lifetime history of insomnia.

A total of 59.3% of the participants were women, 65.3% were white, 24.4% were black, 4.8% were Asian, and 3.9% were classified as "other." The mean age was 47.9 years.

At baseline, all participants were asked about past-year stressful life events, such as divorce, death of spouse, serious illness, and major financial problems, using the Social Readjustment Rating Scale (SRRS-R). The SRRS-R was also used to rate each stressful event for perceived severity and chronicity.

Involuntary cognitive intrusion in response to a stressor in the 7 days following an event was measured using the 8-item intrusion subscale of the Impact of Events Scale. The 26-item Brief COPE scale was used to measure conscious coping strategies used by the participants.

At 1-year follow-up, all participants were examined for insomnia disorder, defined as having insomnia symptoms at least 3 nights a week during a period of at least 1 month with associated daytime impairment.

Results showed a 9.1% insomnia incidence rate. Younger age and being female were significantly associated with insomnia risk (P < .01).

In fact, there was a 2% decrease in the odds for developing insomnia with every 1 year increase in age. Both age and sex were controlled for in all subsequent analyses.

"Stress exposure was a significant predictor of insomnia onset [P < .01], such that the odds of developing insomnia increased by 19% for every additional stressor," the investigators report.

In addition, both severity and chronicity of stress significantly predicted insomnia (both, P < .01). Every 1-point increase on the severity scale increased the odds of developing insomnia by 4%, and every 1-month increase in chronicity increased the odds of insomnia by 2%.

However, only chronicity was a significant moderator between stress exposure and insomnia (P < .01).

Significant Mediators

Significant mediators between stress exposure and insomnia included cognitive intrusion (P < .01) and the coping behaviors of behavioral disengagement (P < .01), substance use (P < .05), and distraction (P < .05).

"The substance use result is quite concerning, given both the high rates of self-medication among individuals with sleep disturbances as well as the known sleep disruptive effects of substances such as alcohol," the investigators write.

They note that tolerance and dose escalation can then lead to "a vicious cycle" of further substance abuse and insomnia.

"The number 1 coping mechanism in the US for adults with sleep difficulties is alcohol use. It does help you fall asleep except, the way it metabolizes in the second half of the night, it leads to sleep fragmentation," added Dr. Pillai.

"We've known for some time that alcohol is disruptive to sleep. But this is the first study to show that alcohol use in response to stress actually leads to chronic insomnia."

As for distraction, the researchers note that that behavior may be beneficial in the short-term but not as a long-term coping strategy.

The behaviors of active coping and of planning were not significantly associated with insomnia.

"Our study is among the first to show that it's not [just] the number of stressors but your reaction to them that determines the likelihood of experiencing insomnia," said Dr. Pillai in a release.

"The number of stressors is really just the beginning," he told Medscape Medical News.

"While a stressful event can lead to a bad night of sleep, it's what you do in response to stress that can be the difference between a few bad nights and chronic insomnia."

He noted that the findings also help identify potential targets for therapeutic interventions, including the possibility of mindfulness-based therapies for supressing cognitive intrusion.

"Although we may not be able to control external events, we can reduce burden by staying away from certain maladaptive behaviors," said Dr. Pillai.

Important Reminder

"This study is an important reminder that stressful events and other major life changes often cause insomnia," Timothy Morgenthaler, MD, president of the AASM, said in a release.

He added that patients who are feeling overwhelmed should talk with clinicians about strategies to reduce stress level and to improve sleep.

Dr. William Kohler

William C. Kohler, MD, medical director of the Florida Sleep Institute in Springhill, told Medscape Medical News that he thought this was a good study but that it had some limitations, as mentioned by the authors.

He noted that self-report studies are always vulnerable to recall bias. On the upside, the study's strengths include its large size and length of follow-up.

Dr. Kohler noted that the results highlight the need for clinicians to ask patients about factors that may contribute to insomnia and possible ways to intervene.

Dr. Kohler, who was not involved with this research, is a past chairman of the AASM's Accreditation Committee. He noted that cognitive intrusion can be an insomnia prevention target.

"That's something we see in insomnia patients in general, where you can't shut your mind off for various reasons. Whether it's from financial stress or emotional stress from sickness in yourself or in individuals you love, at times there are things you can't stop worrying about," he said.

"Being able to develop techniques to alleviate that is very important in potentially preventing the insomnia, although, as the authors mention, it's important to not use drugs or alcohol to try and cover up the problem. That's a maladaptive intervention," said Dr. Kohler.

He added that an important take-away from the study is that an individual's reaction to a stressor should be noted.

"The same severity of stressor may be there for patient A and patient B, but they're going to have different ways of reacting to it and different consequences from that stressor," he said.

"When you see a patient that has a stressor you've identified, you need to be able to give potential positive ways to deal with that stressor."

The study was funded by the National Institute of Mental Health. Dr. Pillai, 1 of the other study authors, and Dr. Kohler have reported no relevant financial relationships. A full list of disclosures from the other 2 study authors are included in the original article.

Sleep. 2014;37:1199-1208. Abstract

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