Health experts have affirmed the importance of sleep for years, but findings from a new study indicate that life, or at least the will to live, may literally depend on getting a good night’s rest. The results indicate that older adults may exhibit considerably higher risk for suicide as much as ten years after experiencing poor subjective sleep quality. Surprisingly, other symptoms of depression need not be present for the risk to increase.

“These findings suggest that sleep disturbances stand alone as a valid risk factor — independent of depressed mood — and worthy of focus as a potential [suicide] risk factor, screening and intervention tool,” said lead author Rebecca Bernert at Stanford University School of Medicine. “Compared to many other known suicide risk factors, sleep disturbances are arguably less stigmatizing and may be undone, and are highly treatable.”

Researchers used a nested case-control study design in which 20 suicide decedents were matched according to age, sex, and community to 400 control subjects, all selected from the Established Populations for Epidemiologic Studies of the Elderly, an ongoing cohort of 14,456 older adults with ten years of followup. Poor sleep was defined to include difficulty falling or staying asleep, waking up too early in the morning, not feeling fully rested after a night’s sleep, or experiencing sleepiness during the day.

The design of the study prevents the scientists from concluding that disturbed sleep causes suicide, nor can the researchers be certain of why the link exists. However, Bernert speculates that a compromise to sleep quality leads to mood disregluation.

“The idea is simple: when we sleep poorly, it impacts how we feel and the way in which we manage our emotions, as well as decision-making,” Bernert said.

Before adjusting for variables relating to depression, subjects that reported poor subjective sleep quality were found to have 40 percent greater odds of committing suicide.  Even after accounting for the effects of depression, the odds remained elevated at 30 percent above those who routinely got adequate sleep.

Bernert and her colleagues are now looking into possible explanations for the association between disturbed sleep and suicide.