The present study aimed to identify mediators in a third potential model to determine whether stress-coping, social support, and resilience mediate the association between probable PTSD and QOL among firefighters and emergency medical technicians working in emergency services. In addition, to analyze the associations between measures mentioned above, we sought to determine how behavior in stress-coping influences components of QOL. The results supported our initial hypothesis, revealing that probable PTSD directly and indirectly predicted mental health state and QOL in models through three mediators.
Effects of independent variables
A linear regression analysis of the univariate showed associations between probable PTSD, QOL, stress-coping, social support, and resilience. Greater probable PTSD directly predicted lower mental health and role/social functioning in QOL. A previous study indicated that war veterans with PTSD exhibited impaired social functioning in QOL , potentially developing impairments in their social lives. Such cases typically involve a cost to society, associated with healthcare utilization . This contributes to the importance of identifying effective methods for protecting individuals from developing PTSD and improving QOL.
The current results revealed that the association between PTSD and QOL involved many confounding factors and independent variables, such as stress-coping and social support. The identified factors were consistent with the findings of previous studies of firefighters and war veterans with PTSD, which indicated that greater stress-coping is predicted by PTSD [61, 62], and Active coping, Positive reframing, and Venting in the Brief COPE can effectively indicate improvement of PTSD symptoms [61, 63, 64]. Most of the stress-coping strategies in the present study directly predicted mental health state in QOL, and more maladaptive coping strategies, including Self-distraction, Self-blame, and Behavioral disengagement, indicated worse mental health and QOL. Holubova et al. reported that participants with mental disorders tend to engage in negative rather than positive coping (adaptive) strategies, and that negative coping (maladaptive) strategies are likely to be associated with lower QOL . Maladaptive coping, which negatively affects QOL, involves Self-distraction, Substance use, Behavioral disengagement, Denial, Self-blame, and Venting. In contrast, adaptive coping, which improves QOL, involves Acceptance, Active coping, Planning, Positive reframing, Humor, Religion, the Use of emotional support, and the Use of instrumental support [65–67]. It is possible that Japanese emergency service workers tend to engage in maladaptive coping, and stress-coping might worsen QOL in rescue workers with PTSD.
In the present study, lower social support was predicted by greater PTSD. Therefore, social support is likely to protect against worsening PTSD . Previous studies indicated that, among war veterans with PTSD, lower family support was associated with PTSD , and poorer social functioning was exhibited compared with war veterans without PTSD . Importantly, social support might promote improvements in QOL among rescue workers.
Greater resilience in the present study was predicted to occur when more adaptive coping strategies were employed, including Active coping, Venting, and Positive reframing, and when avoidance strategies were employed less, including Behavioral disengagement and Denial in stress-coping, in accord with previous studies [35, 69]. In addition, greater resilience exhibited an association with better mental health state and QOL but not probable PTSD. In the current study, we did not find the association between PTSD and resilience reported in a previous study of patients in the Emergency Department, which found that lower resilience predicted the impact of PTSD . Based on the discrepancy between this previous finding and the current results, we propose that probable PTSD may indirectly predict mental health on QOL-mediated stress-coping and social functioning via resilience.
The main findings of the multiple mediation analysis
The results of the mediation analysis without covariates indicated that four stress-coping strategies (Active coping, Behavioral disengagement, Venting, and Positive reframing), social support, and resilience partially mediated the association between probable PTSD and mental health in QOL. The p-values for the association between probable PTSD and resilience in the linear regression model and mediator model analysis were not significant. These findings suggest that resilience was not directly associated with probable PTSD. In contrast, the association between probable PTSD and QOL in the multiple mediation model, as a partial model, was significant.
In a mediator model with covariates, all of the mediator variables predicted QOL, except for stress-coping. Mediator models using two coping strategies (Active coping and Positive reframing) supported our research hypothesis. The findings of the present multiple mediation analysis in the two mediator models revealed that probable PTSD directly predicted stress-coping and social support, which were indirectly associated with QOL when mediated by resilience. In the present study, resilience, as a third mediator, was indicated to have an association with stress-coping and social support. Previous studies indicated a positive association between stress-coping and resilience , revealing that firefighters reported that receiving social support from a boss influenced workers’ resilience . In the current study, we found a significant positive association between resilience and QOL among emergency service workers. Therefore, both stress-coping and social support through resilience appear to help prevent PTSD and maintain good QOL. Thus, Active coping and social support strengthen resilience and improve mental health and QOL among emergency service workers with PTSD.
However, it is possible that Positive reframing in coping strategies skewed the results of the FIML method. Specifically, Positive reframing might lead to type I errors. Therefore, the main findings of the current study suggested that only the mediation model using Active coping exerted protective effects against PTSD and improved mental health in QOL. Active coping to confront difficulties was found to be a particularly important behavior, revealing that this behavior requires practice with social support for the behavior to maintain mental health and QOL among emergency service workers. One method of Active coping is talking about the feelings associated with anxiety, and to receive acceptance from another person as a form of social support.
In addition, mental health screening in emergency service workers at risk from PTSD should include an examination of resilience. If, as indicated in the current study, stress-coping is sometimes negatively associated with QOL, failure to take resilience into account could produce an inaccurate assessment of mental health, as resilience might improve QOL. Although the present findings are suggestive, because this was a cross-sectional study, the causal relationships between PTSD and QOL (mediated by stress-coping, social support, and resilience) could not be confirmed.
This study involved several limitations that should be considered. First, the study sample was composed of only male participants. It is possible that the observed association between PTSD symptoms and QOL would have differed if sex had been included as a confounding factor. Previous studies have also failed to examine the effect of sex; for example, a study by Schnurr et al. on PTSD and QOL included only male veterans . Second, because the current study used a cross-sectional design, we could not confirm a causal relationship between QOL and probable PTSD, or the direction of such a relationship. Third, the use of retrospective data about events that occurred in the past may have led to recall bias, distorting the results. Fourth, statistical analysis using FIML can involve bias when data are not missing at random, because it is based on the assumption of missing at random or missing completely at random . Comparing values between the FIML method and the list-wise deletion method revealed that model fit indices for Positive reframing indicated not to retain good model fit, and the β coefficient on Venting in Brief COPE scores included zero in 95% CIs. The use of these two coping strategies might have confounded the results.
Despite these limitations, the current study had several strengths. To the best of our knowledge, this is the first study to assess the association between PTSD and QOL mediated by stress-coping, social support and resilience among emergency service workers. The mediation analysis indicated associations between stress-coping, social support, and resilience. The current results suggested that stress-coping and social support may strengthen resilience, and resilience may prevent a decline in QOL. The next stage of our research will be to conduct an in-depth longitudinal study to determine whether stress-coping, social support, and resilience influence mental health.