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09-03-2014 | Mental health | Article

Suicide risk greater with disturbed sleep than mental health disorders


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medwireNews: Sleep disturbances are an important risk factor for suicide, say researchers, who found that disturbed sleep contributed more to the risk than mental health disorders in a Japanese population.

The team, led by Manami Kodaka (National Center of Neurology and Psychiatry, Tokyo, Japan), say that “identifying sleep disturbances would be more efficient in suicide prevention than focusing on mental illnesses.”

They note, however, that sleep time in Japan is normally shorter and the prevalence of mental health disorders tends to be lower, compared with Western countries.

“These country-dependent differences may influence the impact that sleep disturbances or mental disorders have on suicide prevention,” they explain.

Kodaka and colleagues surveyed the close family members of 49 adults who had committed suicide and 145 individuals matched for gender, age and municipality.

Their responses showed that the suicide group had a significantly higher prevalence of sleep disturbances, particularly difficult falling asleep, than did the controls, at 75.5% versus 11.0%.

The researchers calculated that the risk of suicide was 21.6 times higher for people with sleep disturbances than for those without. And the risk remained higher after taking into account depression and any mental health disorder, by 9.7 times and 12.7 times, respectively.

The relative risk of suicide among people with mental health disorders was similar to that for people with sleep disturbances, at 21.1. But the estimated population attributable risk percent (PARP) indicated that 56.4% of suicides could be prevented by managing sleep disturbances, compared with just 35.3% by treating mental health disorders.

“These findings suggest that treatment of sleep disturbances […] is more beneficial to suicide prevention and necessitates more strategies that effectively target the prevention or treatment of sleep disturbances,” the researchers remark in Sleep Medicine.

Indeed, in simulated scenarios of varying suicide risk, the estimated posterior probability of suicide was 43.3% for people who had sleep disturbances and were at high risk of suicide, and 6.5% for people who had sleep disturbances and a low risk of suicide.

“Thus, assessing sleep disturbances as a suicide risk index would be effective in both clinical scenarios, and may help identify a target population for intensive continuous care, especially among people already at high risk,” the researchers conclude.

medwireNews ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2014

By Lucy Piper, Senior medwireNews Reporter

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