Prevalence and predictors of sleep and trauma symptoms in wildfire survivors

Objective: This study aimed to establish the prevalence and to identify predictors of insomnia, nightmares and post-traumatic stress disorder (PTSD) in wildfire survivors.

Method: A total of 126 (23 males, 102 females, and 1 nonbinary individual, M age = 52 years, SD = 14.4) wildfire survivors from Australia, Canada and the USA took part in an online survey. Participants completed a demographic questionnaire and self-report measures including: The Insomnia Severity Index (ISI), PTSD Checklist for DSM-5 (PCL-5), and Disturbing Dream and Nightmare Severity Index (DDNSI).

Results: Results showed that 49.2% of the sample reported clinical insomnia on the ISI, 28.7% reported nightmares on the DDNSI, and 77.88% reported PTSD symptoms on the PCL-5. Fear for life of others ( Pearson’s r = .40, .21, .31), and the impact of smoke ( Pearson’s r , .47, .25,.41) significantly correlated with insomnia, nightmares and PTSD symptoms, respectively. Hierarchical regression showed that smoke was a significant predictor of insomnia ( 𝛽= .17, p < .05, 95% CI , 0.15 1.49), and insomnia predicted both of PTSD ( 𝛽= .27, p < .05, 95% CI , 0.26 –1.05), and nightmares ( 𝛽= .19, p = .04, 95% CI , 1.01 –1.45) scores. Conclusion: Insomnia, nightmares and PTSD are highly prevalent in wildfire survivors. Smoke, one of the trauma-related factors, was found to be as a significant predictor of insomnia; and insomnia was a significant predictor of both PTSD and nightmares. Future longitudinal studies are needed to establish which disorder emerges first as a result of smoke