Actor comedian Robin Williams committed suicide after his wife went to their bedroom for the evening and he went to a guest room - there were no rumblings of trouble in the relationship so presumably he was being considerate and his poor sleep would have kept her awake. He had suffered from bouts of depression for decades but even without that, the poor sleep quality could have been a warning sign, finds a new paper.

Poor sleep quality, independent of a depressed mood, appears to be associated with an increased risk for suicide in older adults, finds a study written by Rebecca A. Bernert, Ph.D., of the Stanford University School of Medicine, California, and colleagues.

Suicide is a preventable public health problem and accounts for almost one million deaths annually worldwide. Late life is characterized by an increased prevalence of sleep complaints and disproportionately elevated rates of suicide. The study sample included 420 individuals (400 control patients and 20 patients who died from suicide) who were selected from 14,456 participants.

Robin Williams. Credit: Wikipedia

The authors examined the risk for suicide associated with poor reported sleep in a group of older adults (with an average age of nearly 75 years) during a 10-year observation period.

Those individuals who reported poorer sleep quality at baseline had a 1.4 times increased risk for suicide. When authors controlled for the effects of a depressed mood, people with poorer sleep at baseline still demonstrated a 1.2 times greater risk for suicide during the 10-year observation period. Two sleep factors in particular – difficulty falling asleep and nonrestorative sleep – were associated with increased suicide risk.

Self-reported Sleep Quality at Baseline as a Predictor of Risk for Death by Suicide. The receiver operating characteristic curve for baseline Sleep Quality Index total scores distinguishes cases (20 suicide decedents) from 400 age and sex–matched control subjects. Higher Sleep Quality Index total scores reflect poorer subjective sleep quality. Credit: doi:10.1001/jamapsychiatry.2014.1126

"We suggest that poor subjective sleep quality may therefore represent a useful screening tool and a novel therapeutic target for suicide prevention in late life."