Association of hospital-diagnosed sleep disorders with suicide: a nationwide cohort study

INTRODUCTION: Sleep disorders and psychiatric disease are closely related, and psychiatric diseases are associated with elevated suicide risks. Yet, the association between sleep disorders and suicide remains to be assessed using a consistent measure of sleep disorders. OBJECTIVES: The aim of this study was to examine whether people with a hospital-diagnosis of sleep disorders had higher suicide rates than people with no diagnosis. METHODS: In a cohort study, nationwide data on all persons aged 15+ years living in Denmark during 1980-2016 were analysed. Sleep disorders were identified through diagnoses recorded during contacts to somatic hospitals. Incidence Rate Ratios (IRR) were estimated using Poisson regression models and adjusted for relevant covariates. RESULTS: In all, 3,674,563 males and 3,688,164 females were included, of whom 82,223 (2.2%, mean age: 50.2, SD: 17.5) males and 40,003 (1.1%, mean age: 50.6, SD: 19.9) females had sleep disorder diagnoses. Compared to those with no sleep disorders, the adjusted IRRs for suicide were 1.6 (95% CI, 1.4-1.7) and 2.2 (95% CI, 1.8-2.6) for males and females with sleep disorders, respectively. Excess rates for narcolepsy were found for males (IRR:1.2, 95% CI, 1.0-1.5) and females (IRR:3.3, 95% CI, 3.0-4.1), and for sleep apnea in males (IRR:1.8, 95% CI, 1.5-2.2). Males and females had IRRs of 4.1 (95% CI, 3.1-5.5) and 7.0 (95% CI, 4.8-10.1), respectively, 6 months after being diagnosed with a sleep disorder. CONCLUSIONS: Sleep disorders were associated with higher suicide rates even after adjusting for pre-existing mental disorders. Our findings suggest attention towards suicidal ideation in patients suffering from sleep disorders is warranted. DISCLOSURE: Disclosures and Acknowledgements: Adam Spira has received honoraria for serving as a consultant to Merck and from Springer Nature Switzerland AG for guest editing special issues of Current Sleep Medicine Reports. The other authors report no conflict of in