Association between probable posttraumatic stress disorder and quality of life in emergency service workers: a mediation analysis using a third potential model with both in parallel and in series effects; a cross-sectional study

Abstract

Background The present study used a third potential model with both in parallel and in series effects to identify mediators influencing the association between probable posttraumatic stress disorder (PTSD) and quality of life (QOL). In addition, we sought to clarify how stress-coping behaviors influence components of QOL. Methods Participants were 220 emergency service workers. PTSD was assessed using the Impact of Event Scale-Revised (IES-R). QOL was assessed using the MOS 36-Item Short-Form Health Survey (SF-36). Mediation analysis and moderated mediation analysis of interaction effects with a third potential model were used to examine the effects of stress-coping (Brief COPE scores), social support (Multidimensional Scale of Perceived Social Support [MSPSS] scores), and resilience (Connor-Davidson Resilience Scale [CD-RISC] scores) on the association between probable PTSD and QOL. Results The mediation analysis with confounders suggested an acceptable model fit. The moderated mediation analysis did not indicate differences in the moderators. IES-R scores were significantly positively associated with Active coping, Venting, and Positive reframing in Brief COPE scores and were significantly negatively associated with MSPSS scores. Active coping, Venting, and Positive reframing in Brief COPE and MSPSS scores was significantly positively associated with CD-RISC scores, which were significantly positively associated with SF-36 scores. A sensitivity analysis comparing the results between the full information maximum likelihood method and the list-wise deletion method indicated that the 95% confidence interval included zero and a good model fit was not maintained for indices of coping strategies in Venting and Positive reframing in Brief COPE scores. Conclusions Active coping in response to stressful situations is an important behavior for maintaining good mental health among emergency service workers. In addition, Active coping in stress-coping and social support may have strengthened participants’ resilience, and resilience may have improved QOL. However, Positive reframing and Venting might have confounded the results because they exhibited a Not Missing At Random data distribution. Screening of mental health and QOL should include simultaneous assessment of stress-coping, social support, and resilience. Although the present findings are suggestive, because this was a cross-sectional study, causal relationships between PTSD and QOL mediated by three mediators could not be confirmed.