The way in which people cope with stress may increase their risk for insomnia, according to a recent study.

Researchers found that coping with a stressful event through behavioral disengagement -- giving up on dealing with the stress -- or by using alcohol or drugs each significantly mediated the relationship between stress exposure and insomnia development.

"Our study is among the first to show that it's not the number of stressors, but your reaction to them that determines the likelihood of experiencing insomnia," Vivek Pillai, lead author of the study, said in a statement. "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."

Surprisingly, the coping technique of self-distraction -- such as going to the movies or watching TV -- also was a significant mediator between stress and incident insomnia. The research team found that cognitive intrusion -- recurrent thoughts about the stressor -- was a significant and key mediator, accounting for 69 percent of the total effect of stress exposure on insomnia.

For the study, researchers analyzed data from a community-based sample of more than 2,800 good sleepers with no lifetime history of insomnia.

At the beginning the study, participants reported the number of stressful life events that they had experienced in the past year, such as a divorce, serious illness, major financial problem, or the death of a spouse. They also reported the perceived severity and duration of each stressful event.

They were also given questionnaires that measured levels of cognitive intrusion and identified coping strategies in which participants engaged in the seven days following the stressful event.

A follow-up assessment after one year identified participants with insomnia disorder, which was defined as having symptoms of insomnia occurring at least three nights per week for a duration of one month or longer with associated daytime impairment or distress.

"This study is an important reminder that stressful events and other major life changes often cause insomnia," said American Academy of Sleep Medicine President Dr. Timothy Morgenthaler. "If you are feeling overwhelmed by events in your life, talk to you doctor about strategies to reduce your stress level and improve your sleep."

Researchers said their results identified potential targets for therapeutic interventions to improve coping responses to stress and reduce the risk of insomnia.

The findings were recently published online in the monthly, peer-reviewed journal Sleep.