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The Correlation Between Sleep Disturbance and Suicide

The Correlation Between Sleep Disturbance and Suicide

The battle against suicide took a step backward between 2011 and 2012. According to the CDC, while 8 of the 10 most common causes of death in the US showed statistically significant reductions in the death rate over the span of merely 1 year, one cause of death among the top 10 showed a significant increase—suicide.1 More than 40,000 Americans will complete suicide this year. Clearly more needs to be understood and done to reverse these trends.

All psychiatrists know the risk factors for suicide. Some are unmodifiable, such as advancing age, male sex, and being white. Others are potentially modifiable, such as depression, drug abuse, hopelessness, and social isolation. Among the newest modifiable risk factors to join the list are insomnia and nightmares.

© sam100/shutterstock.com© sam100/shutterstock.com
The first reports of an association between insomnia and suicide death appeared about 25 years ago.2 The passage of time has produced a voluminous literature of more than 60 original research reports that show a statistical association between sleep disturbance and suicidal thinking, suicidal behavior, and suicide death. These reports come from North America, Europe, and Asia, and encompass children and adolescents, young adults, and the elderly.

The clever skeptic would guess that the association between sleep disturbance and suicide is spurious and is better explained by the well-known association of sleeping problems with depression; therefore, it must actually be the depression that is driving the association with suicide. And yet, when the presence and intensity of depression are controlled for within the statistical analysis, the relationship between sleep problems and suicide still stands. The odds ratio between insomnia and suicidal ideation is approximately 2.0. Moreover, the intensity of suicidal ideation co-varies with the intensity of insomnia during the course of clinical treatment for depression.3

While much of the relevant literature has been about insomnia and suicide, there are reports that more specifically link nightmares with suicide. The association between nightmares and suicide (as judged by the size of the odds ratio) may be greater than the association between insomnia and suicide, per se. The odds ratio for insomnia and suicidal behavior has been reported as 7.0, while the odds ratio for nightmares and subsequent suicidal behavior is as high as 8.2.4 In addition, hypersomnia may also be linked to suicide.5

Risk factors

What explains these associations, especially when 2 seemingly opposite phenomena such as insomnia and hypersomnia are linked to suicide? One explanation is the simple concept of “burden of illness.” It is well known that a chronic medical illness is a risk factor for suicide, so perhaps the burden of living with insomnia or hypersomnia becomes the “straw that breaks the camel’s back.”

The strength of the association between sleep disturbance and suicide would suggest that many suicide deaths happen at night, yet the opposite seems to be the case. Very few suicide deaths occur during the nighttime hours, followed by a sharp rise in suicide death rates through the morning hours and a decline again toward evening.6 Therefore, if sleep disturbance is related to suicide, it may be through the effects of sleep disturbance on daytime psychological or physiological function.

Both insomnia and hypersomnia are associated with impairments in cognitive functioning.7 Patients with insomnia have trouble in problem solving, and deficits in problem solving have been described in persons who have survived suicide attempts.8 In this scenario, the person who is dealt a major setback, such as a broken relationship or job loss, is unable to produce a solution to the problem if he or she has insomnia; this leads to the worst possible solution. Hypersomnia, like insomnia, is also associated with deficits in cognition.


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