Objective: Temporal patterns for suicide over a 24-hour period have shown mixed results among prior studies. However, analyses of 24-hour temporal patterns for wakeful actions including suicidal behavior should adjust for expected sleep requirements that inherently skew such activities to conventional wakeful times. This study analyzed the time-of-day for suicide cases from the Australian population for the year 2017, adjusting for expected sleep patterns. Identification of time-of-day trends using this methodology may reveal risk factors for suicide and potentially modifiable contributors.
Methods: The Australian National Coronial Information System database was accessed, and data for completed suicide were extracted for the most recent completed year (2017). Time of suicide was allocated to one of four 6-hourly time bins across 24 hours, determined from time last seen alive and time found subsequently. Prevalence of suicide for each time bin was adjusted for the likelihood of being awake for each bin according to sleep-wake norms published from a large Australian community survey. Observed prevalence of suicide was compared to expected values predicted from likelihood of being awake across each time bin calculated as a standardized incidence ratio (SIR).
Results: For the year 2017, there were 2,808 suicides, of which 1,417 were able to be allocated into one of four 6-hourly time bins. When compared to expected values, suicides were significantly more likely to occur in the overnight bin (2301–0500; SIR = 3.93, P < .001).
Conclusions: Higher-than-expected rates of suicide overnight associated with nocturnal wakefulness may represent a modifiable risk factor for triggering suicide events.
Continue Reading...
Members enjoy unlimited free PDF downloads as part of their subscription! Subscribe today for instant access to this article and our entire library in your preferred format. Alternatively, you can purchase the PDF of this article individually.
Gallerani M, Avato FM, Dal Monte D, et al. The time for suicide. Psychol Med. 1996;26(4):867–870. PubMedCrossRef
Preti A, Miotto P. Diurnal variations in suicide by age and gender in Italy. J Affect Disord. 2001;65(3):253–261. PubMedCrossRef
Boo J, Matsubayashi T, Ueda M. Diurnal variation in suicide timing by age and gender: evidence from Japan across 41 years. J Affect Disord. 2019;243:366–374. PubMedCrossRef
Perlis ML, Grandner MA, Brown GK, et al. Nocturnal wakefulness as a previously unrecognized risk factor for suicide. J Clin Psychiatry. 2016;77(6):e726–e733. PubMedCrossRef
Tubbs AS, Fernandez FX, Perlis ML, et al. Suicidal ideation is associated with nighttime wakefulness in a community sample. Sleep. 2021;44(1):zsaa128.
Chu C, Hom MA, Rogers ML, et al. Is insomnia lonely? exploring thwarted belongingness as an explanatory link between insomnia and suicidal ideation in a sample of South Korean university students. J Clin Sleep Med. 2016;12(5):647–652. PubMedCrossRef
Vandewalle G, Archer SN, Wuillaume C, et al. Functional magnetic resonance imaging-assessed brain responses during an executive task depend on interaction of sleep homeostasis, circadian phase, and PER3 genotype. J Neurosci. 2009;29(25):7948–7956. PubMedCrossRef
Verweij IM, Romeijn N, Smit DJ, et al. Sleep deprivation leads to a loss of functional connectivity in frontal brain regions. BMC Neurosci. 2014;15(1):88. PubMedCrossRef
Chakravorty S, Smith RV, Perlis ML, et al. Circadian pattern of deaths due to suicide in intoxicated alcohol-dependent individuals. J Clin Psychiatry. 2018;79(6):17m11800. PubMedCrossRef
Pigeon WR, Pinquart M, Conner K. Meta-analysis of sleep disturbance and suicidal thoughts and behaviors. J Clin Psychiatry. 2012;73(9):e1160–e1167. PubMedCrossRef
Wright KM, Britt TW, Bliese PD, et al. Insomnia as predictor versus outcome of PTSD and depression among Iraq combat veterans. J Clin Psychol. 2011;67(12):1240–1258. PubMedCrossRef
Farrell-Carnahan L, Barnett S, Lamberty G, et al. Insomnia symptoms and behavioural health symptoms in veterans 1 year after traumatic brain injury. Brain Inj. 2015;29(12):1400–1408. PubMedCrossRef
Perlis ML, Grandner MA, Chakravorty S, et al. Suicide and sleep: is it a bad thing to be awake when reason sleeps? Sleep Med Rev. 2016;29:101–107. PubMedCrossRef
Appleton SL, Reynolds AC, Gill TK, et al. Waking to use technology at night, and associations with driving and work outcomes: a screenshot of Australian adults. Sleep (Basel). 2020;43(8):zsaa015. PubMedCrossRef
Van Orden KA, Witte TK, Cukrowicz KC, et al. The interpersonal theory of suicide. Psychol Rev. 2010;117(2):575–600. PubMedCrossRef
Hom MA, Chu C, Schneider ME, et al. Thwarted belongingness as an explanatory link between insomnia symptoms and suicidal ideation: findings from three samples of military service members and veterans. J Affect Disord. 2017;209:114–123. PubMedCrossRef
Chu C, Hom MA, Rogers ML, et al. Insomnia and suicide-related behaviors: a multi-study investigation of thwarted belongingness as a distinct explanatory factor. J Affect Disord. 2017;208:153–162. PubMedCrossRef
Zuromski KL, Cero I, Witte TK. Insomnia symptoms drive changes in suicide ideation: a latent difference score model of community adults over a brief interval. J Abnorm Psychol. 2017;126(6):739–749. PubMedCrossRef