Sleep is known to be important for physical as well as emotional well-being. Mood and anxiety disorders commonly present with a variety of sleep problems including initial, middle and early morning insomnia. Although the association of mood disorders and anxiety disorders in suicide is established, the independent contribution of insomnia to suicide risk is less well studied.
Bjorngaard and colleagues recently published a results of a Norwegian study on this issue in the Journal Sleep. Using data from the HUNT epidemiologic study, they conducted an analysis of suicide risk over a twenty year follow-up period.
Over 75,000 subjects completed baseline assessment of sleep problems as assessed by a single question: "During the last month have you had any problems falling asleep or sleep disorders? This question had four levels of response listed below with the prevalence of endorsement in
(parentheses):- almost every night (3%)
- often (5%)
- sometimes (31%)
- never (62%)
Endorsing sleep problems almost every night or often was more common among women (10% vs 5% for men) and for those over 50 years of age (11% versus 5% for those 50 and under.
After controlling for sociodemographic variables, those respondents endorsing sleep problems almost every night had a four fold increase in risk for suicide over the follow up period. Controlling for alcohol use and self-report of anxiety and depressive symptoms reduced the size of this effect by about 50% but did not eliminate the independent effect of sleep problems and suicide risk.
The authors noted the link between sleep problems and suicide risk appeared stronger in those younger and the index assessment. Interestingly, the link also appeared primarily in those not taking sleeping pills or sedatives. Individuals reporting regular use of sleeping aids did not have an association between self-reported sleep problems and suicide rates.
Physical illnesses and chronic pain increase risk for sleep problems as well as for suicide. The study did control for presence of a long-standing medical illness, body mass index and decreased functional ability. Of note, suicide risk was not increased for those respondents who endorsed regular use of "painkillers".
This study supports further research into the independent association of sleep problems in suicide risk. In an accompanying editorial, Dr. W. Vaughn McCall notes the need for exploring "physiologic/neurochemical and psychological mechanisms" for link between sleep problems and suicide risk. Further understanding of the role of sleep apnea in this association is also needed.
New Mexico wildflowers and butterflies from author's private collection.
Bjørngaard JH, Bjerkeset O, Romundstad P, & Gunnell D (2011). Sleeping Problems and Suicide in 75,000 Norwegian Adults: A 20 Year Follow-up of the HUNT I Study. Sleep, 34 (9), 1155-9 PMID: 21886352 
