Sleep and suicide: an analysis of a cohort of 394,000 Taiwanese adults.

BACKGROUND

Sleep problems may lead to, or be symptomatic of, depression and other mental illnesses yet few studies have investigated their association with suicide risk.

DESIGN

Prospective cohort study.

SETTING

Taiwan.

PARTICIPANTS

393,983 men and women aged 20 or above participating in the MJ health check-up programme.

RESULTS

There were 335 suicides over a mean of 7.4 years follow-up. There was a reverse J-shaped association between sleep duration and suicide risk. When compared with those sleeping 6-8 h per night the adjusted hazard ratios (95% confidence intervals) for suicide associated with 0-4, 4-6 and >8 h sleep were 3.5 (2.0-6.1), 1.5 (1.1-1.9) and 1.5 (1.1-2.0), respectively. People requiring sleeping pills to get to sleep (1.2% participants) were at over 11-fold increased risk; difficulty falling asleep (11.5% participants), frequent dreaming (16.7%) and being easily awoken (30.6%) were associated with a 2.0-, 1.6- and 1.3-fold increased risk of suicide, respectively.

CONCLUSIONS

Less than 6 h sleep duration, sleep disturbances and reported use of sleep medicines are markers of suicide risk. Sleep problems should be assessed when evaluating suicide risk.