Introduction
Studies consistently demonstrate a link between subjective sleep disturbances and the continuum of suicidality, although this evidence primarily comes from retrospective, cross-sectional studies using limited items to assess sleep. Longitudinal assessment of well-defined and measured sleep/wake behaviors with high-risk individuals are needed to enhance the specificity of near-term suicide risk detection and render concrete targets for suicide prevention.
Methods
Participants (N=46) included ultra-high-risk adolescents (N=29 ages 12-18) and college students (N=17 ages 18-24). For up to 12 weeks, participants wore an actigraph to yield objective data on sleep/wake, and concurrently completed daily cellphone-based ratings of subjective sleep and suicidality. Generalized estimating equations were used to examine the association between sleep parameters (subjective and objective) and the odds of next-day suicidal outcomes (i.e., passive death wish [PDW], suicidal ideation, suicidal intent) controlling for age, gender, and depression severity.
Results
Significant quadratic relationships were observed between actigraphy-derived total sleep time (TST) and probability of next-day PDW (Z=3.7, p=0.0002), suicidal ideation (Z=2.1, p=0.04), and suicidal intent (Z=2.78, p=0.006), with increasing suicidality at low and high values of TST. Low sleep efficiency (<75%) was associated with increased odds of next-day PDW (OR=1.24, Z=2.07, p=0.038). Subjectively (sleep diary measures), low sleep quality (<50 on 100-point scale) was associated with increased odds of next-day suicidal ideation (OR=1.57, Z=3.42, p<0.001), and longer sleep onset latency (>20 minutes) with next-day suicidal intent (OR=3.00, Z=2.37, p=0.018).
Conclusion
Poor sleep health may signal increasing suicide risk, and are modifiable risk factors. We document a significant temporal association whereby objectively-derived short and long TST and low sleep efficiency, as well as subjective sleep quality and sleep onset latency, predicts next day’s suicidality. Further understanding of the temporal association between sleep and suicidality may hold promise to inform real-time monitoring and preventive strategies. Interventions targeting these factors may therefore help reduce suicidality in high-risk youth.
Support
American Foundation for Suicide Prevention; University of Pittsburgh Clinical and Translational Science Institute