Results of a new study show that every one-hour increase in sleep duration was associated with a 72 percent decrease in the likelihood of moderate or high suicide risk, in comparison with low risk. Data were adjusted for age, gender, race/ethnicity, education and age of onset of sleep difficulties.

"We were surprised by the strength of the association between sleep duration and suicide risk," said primary author Linden Oliver, MA, clinical research coordinator for the University of Pennsylvania Behavioral Sleep Medicine Research Program in Philadelphia, Pa. "A 72 percent decrease in the likelihood of moderate or high suicide risk with a one-hour increase in sleep is interesting given the small sample size."

The research abstract was published recently in an online supplement of the journal SLEEP, and Oliver will present the findings Tuesday, June 4, in Baltimore, Md., at SLEEP 2013, the 27th annual meeting of the Associated Professional Sleep Societies LLC.

Data from two studies of insomnia were merged for the present analysis. Of the 471 total subjects, 73 indicated suicide risk using the Mini International Neuropsychiatric Interview; 55 were classified as low suicide risk and 18 were classified as moderate or high risk. Subjects without any suicide risk were excluded, as the parent studies were still enrolling subjects

According to the authors, sleep loss is associated with depression, executive dysfunction and poor decision making. However, few studies have investigated the role of short sleep duration in suicidal ideation.

"These results further highlight the importance of obtaining adequate amounts of sleep," said Oliver.

The American Academy of Sleep Medicine reports that about 10 to 15 percent of adults have an insomnia disorder with distress or daytime impairment. According to the CDC, suicide is the 10th leading cause of death in the U.S., accounting for more than 38,000 deaths each year.