Association between change in sleep duration and posttraumatic stress symptoms in natural disaster victims: the mediating role of resilience

Objective: This study investigated the association between changes in sleep duration after disaster and post-traumatic stress disorder (PTSD) symptoms and the mediating role of resilience on the association. Methods: Data were collected from 2951 Korean adults who were victims of a natural disaster and did not have any mental or medical illnesses before the event. They completed a long-term survey on changes in life for disaster victims using computer-aided personal interviews. Changes in sleep duration before and one month after experiencing a disaster were assessed using a self-reported questionnaire. Resilience levels and PTSD symptoms were measured using the Brief Resilience Scale and the Impact of Event Scale – Revised, respectively, and more than 33 of the IES-R score items were defined as significant PTSD symptoms. Multivariate logistic regression was used to examine the associations between changes in sleep duration and PTSD symptoms. Additionally, mediating studies were conducted to identify the role of resilience on the association. Results: Compared with participants without significant PTSD symptoms, those with PTSD symptoms were more likely to be older and female (group without significant PTSD symptom: mean age = 56.12 ± 18.70 years, female sex = 49.24%; group with significant PTSD symptoms: mean age = 60.88 ± 15.66 years, female sex = 59.52%). Compared with disaster victims without changes in sleep duration, those who had shorter sleep duration after disaster had a higher risk of significant PTSD symptoms (OR = 2.89, 95% Cl = 2.31–3.62, p < 0.001). In the mediating study, resilience level significantly mediated the relationship between reduced sleep duration and PTSD symptoms (direct effect: β = 0.208, 95% Cl = 0.166–0.250, p < 0.001; indirect effect: β = 0.007, 95% Cl = 0.002–0.011, p < 0.001; total effect: β = 0.215, 95% Cl = 0.173–0.257, p < 0.001). Conclusion: This study revealed that individuals with reduced sleep duration after disaster had a higher risk of PTSD symptoms, while those with increased sleep duration did not. In addition, mediating effects of resilience level on the relationship between reduced sleep duration and significant PTSD symptoms were observed.