New research suggests that insomnia symptoms mediate the relationship between alcohol use and suicide risk, and that this mediation is moderated by gender.

Researchers found that alcohol use was significantly associated with suicide risk among women. They also found that insomnia symptoms explained a significant proportion of the relationship between alcohol and suicide risk. For men, there was no direct effect of alcohol use on suicide risk, but there was a significant indirect effect of alcohol use increasing suicide risk through insomnia symptoms.

"These results are important as they help demonstrate that alcohol use is associated with an increase in suicide risk, and that this increase may be partially due to insomnia symptoms," Michael Nadorff, principal investigator of the study, said in a statement. "By better understanding this relationship, and the mechanisms associated with increased risk, we can better design interventions to reduce suicide risk."

According to the American Academy of Sleep Medicine, about 10 percent of people have chronic insomnia disorder, which involves a sleep disturbance and associated daytime symptoms that have been present for at least three months. About 15 to 20 percent of adults have short-term insomnia disorder. Both types of insomnia are more common in women than in men.

For the study, researchers collected data from 375 undergraduate students at a large, public university in the southeastern United States. They completed an online questionnaire that examined symptoms. Nightmares, alcohol use and suicide risk.

The Centers for Disease Control and Prevention reports that excessive alcohol use leads to about 88,000 deaths in the U.S. each year and shortens the life of those who die by almost 30 years. Accounting for more than 38,000 deaths each year, suicide is the 10th leading cause of death in the U.S. according to the CDC.

The findings are detailed in the Journal of Clinical Sleep Medicine.