“This appears to be the first [set of] data to suggest that circadian factors may contribute to suicidality and help explain why insomnia is also a risk factor for suicidal ideation and behavior,” said Michael Perlis, PhD, Associate Professor in the Department of Psychiatry and Director of the Penn Behavioral Sleep Medicine Program at the University of Pennsylvania in Philadelphia. “These results suggest that not only are nightmares and insomnia significant risk factors for suicidal ideation and behavior, but just being awake at night may in and of itself be a risk factor for suicide,” he added.
Previous research suggesting that more suicides occur during the day failed to account for the proportion of the population that is awake at each given hour, according to the authors. The current study involved archival analyses of the National Violent Death Reporting System, which provided data for the estimated time of fatal injury, and the American Time Use Survey, which provided an hourly proportion of the American population that is awake. Time of fatal injury was categorized into one-hour segments, and the hourly distribution of these data were weighted by the proportion of people awake at each hour and scaled to 100%. A total of 35,332 suicides were included in the analysis.
An important implication of the study is that the treatment of insomnia may be one way to reduce suicide risk, according to Dr. Perlis. The American Academy of Sleep Medicine reports that approximately 10% of adults have a chronic insomnia disorder that has lasted at least three months.