A vast number of studies have highlighted the increased risk of experiencing traumatic events among emergency and rescue personnel (1), pertaining not only to events experienced as a victim, but also those experienced as a witness (2). Indeed, studies show that between 80 and 100% of emergency and rescue personnel have experienced at least one traumatic event during service (3–5). Due to this accumulation of traumatic events, emergency and rescue personnel experience higher levels of psychological stress and are consequently at greater risk of developing mental health problems (6, 7).

Meta-analyses and systematic reviews have demonstrated that the point prevalence of PTSD in emergency and rescue personnel lies at ~10% (1, 8–10), as compared to 1.3–3.5% in the general population (1, 10, 11). However, prevalence rates vary broadly across different studies, ranging from 0 to 46% (9). Moreover, emergency and rescue personnel show an increased prevalence of comorbid psychiatric symptoms such as depression, substance abuse, and social dysfunction (12).

In recent years, the scientific focus has shifted more toward health-promoting factors (13), and the concept of resilience has received increased attention as a protective factor in this regard (14). While there is no generally accepted definition of resilience, the concept might best be described as the process of adapting well in the face of adversity, trauma, tragedy, threats, or significant sources of stress (15). Surprisingly, studies analyzing resilience directly in emergency and rescue personnel are lacking, although the few studies comparing resilience between rescue personnel and the general population reported higher resilience among rescue personnel (16).

To date, almost all studies exploring PTSD symptoms or health-promoting factors in this group have focused on professional rescue personnel, while data on voluntary rescue and emergency personnel are sparse (17). A recent study found that seasonal firefighters had a higher risk of developing PTSD than did professional firefighters (18).

In Switzerland, the alpine rescue service (ARS) is a voluntary organization. Mountain rescuers receive training consisting of first aid and rescue techniques for the alpine environment for summer and winter, with additional options for specialized training (e.g., specialist for helicopter rescues in alpine environment, rescue dog handler).

Research has shown that traumatic events like avalanches, rockfalls, or falls while climbing are frequent in alpine environments (19). Indeed, in 2020, the ARS received a total of 999 emergency calls and assisted 1,319 people during their missions (20).

The present study aimed to assess (a) the frequency and types of traumatic situations during mountain rescue missions and (b) the frequency of possible PTSD among mountain rescuers. Moreover, we sought to examine (c) the extent of resilience among mountain rescuers as compared to the general population using the samples of Leppert et al. (21), Wagnild and Young (22), and Callegari et al. (23), and (d) differences between mountain rescuers with and without possible PTSD. Finally, (e) we evaluated predictors of resilience and severity of PTSD symptoms.

The main findings of our study indicate that although a high number of mountain rescuers had experienced traumatic events, only a very small number met the cut-off for a possible PTSD. Moreover, we found high resilience scores within the sample of mountain rescuers. The most reliable predictor of the severity of PTSD symptoms was low sense of coherence, followed by poor quality of sleep, a low level of perceived social support, and a high number of different traumatic events as a victim. Further results indicated that low perceived stress and high sense of coherence were the strongest predictors of resilience in our sample.

The number of traumatic events experienced by the mountain rescuers was much higher than in the general population, with 71% of our sample having experienced a traumatic event during their missions. Nevertheless, this proportion was lower than in other studies covering emergency and rescue personnel (prevalences between 80 and 100%) (5, 52–55). The most important difference between our sample and the samples investigated in previous studies appears to be that the ARS is a voluntary organization and therefore has a lower rate of missions per person. Moreover, there is evidence that this subgroup has a higher risk of developing mental disorders due to greater structural barriers to the treatment of psychopathological consequences of traumatic events. The ARS has about 800–900 missions each year, resulting in an average of 3.4 missions per mountain rescuer annually. However, the numbers of missions per rescuer varied greatly across the sample, with 10% of the rescuers carrying out ~60% of the missions. Although the actual percentage of traumatic events is slightly lower than that reported for professional rescue workers, the number of traumatic events is still high. As such, the low prevalence of possible PTSD (1%) and subsyndromal PTSD (3%) is all the more surprising.

Although the present findings, along with the findings from previous studies (2, 56), revealed a rather low prevalence of possible PTSD in relation to the high levels of exposure to traumatic events, the prevalence of 1% found in the present ARS sample is far lower than in previous studies covering emergency and rescue personnel (~10%) (57) and even compared to the prevalence in the general population (1.3–3.5%) (1). In detail, Streb et al. (16) found a PTSD prevalence of ~4.3 % among paramedics, and Misra et al. (58) reported a prevalence of around 4% among the rescue personnel who responded to the 2005 London bombings. However, these two samples differ from the sample investigated in the current study, since they consisted of professional rescue workers. Moreover, Misra et al. (58) examined the prevalence following a single traumatic event. Our results are in contrast to existing research covering voluntary rescue and emergency personnel, which reported a slightly higher PTSD prevalence compared to professional rescue personnel (59–61).

A previous study on PTSD symptoms caused by mountain accidents revealed that between 14 and 31% of victims still showed different symptoms of PTSD 9 months after rock climbing accidents (62). Another study reported a PTSD symptom prevalence of 28% among mountaineers suffering an avalanche accident and of 43% among fully buried avalanche victims (63).

A possible explanation for the comparably lower prevalence of possible PTSD in our sample is the lower frequency of missions as compared to professional rescue personnel. Moreover, the ARS personnel seem to be exposed to fewer different types of traumatic events compared to other professional rescue personnel (64, 65). A recent study found that a larger number of different traumatic events increases the risk of developing PTSD symptoms (66). A further explanation might lie in the higher percentage of indirect traumatic events (about 60%) compared to direct traumatic events (30%), as indirect exposure has been associated with a lower risk of developing PTSD symptoms than direct exposure (2). A study by Sommer and Ehlert (19), which examined PTSD symptoms in Swiss mountain guides, found that the emotional reaction to traumatic events was low, pointing at a high tolerance of objectively dangerous situations.

Resilience among the mountain rescuers of our sample was found to be higher than in all three comparison samples representing the general population (21–23). This corresponds to recent evidence indicating higher resilience among German paramedics compared to the general population (16). An Italian study also found a high level of resilience in emergency personnel, and identified self-efficacy, collective efficacy, and sense of community as the main protective factors for mental health (67). Since our study provides only single time point data, we are unable to draw definitive conclusions on the etiology of the high resilience found in our ARS sample. One possible explanation lies in self-selection, insofar as individuals with higher resilience may be more likely to join the ARS in the first place and to remain with the ARS after joining. As another potential explanation, it may be that the level of work experience influences resilience, as our data suggest that mountain rescuers with less work experience (<7 years) show less resilience than those with more work experience (>23 years). This is in line with the findings of Gayton and Lovell (68), who reported that resilience in ambulance paramedics increased with time in service. In general, our findings support the line of research pointing to resilience as a dynamic factor rather than a personal trait (69).

The present data indicate that mountain rescuers meeting the criteria for a atleast subsyndromal PTSD differ from those without at least subsyndromal PTSD with regard to certain variables. Mountain rescuers with subsyndromal PTSD were significantly less resilient, showed poorer general mental health, lower sense of coherence, lower perceived social support, worse quality of sleep, and more perceived stress. These findings demonstrate that even subsyndromal PTSD results in detectable changes in mental wellbeing. This corresponds to previous studies that reported an association of subsyndromal PTSD with a lower level of functioning (70–72) as well as impairments in social and work-related matters, resulting in a diminished quality of life (30, 73). However, since effect sizes in the present study were small (r < 0.3) and the two group sizes differed considerably, we focused on predictors of severity of PTSD symptoms rather than on group differences.

To find predictive factors for the severity of PTSD symptoms in emergency and rescue personnel, it might be helpful to create screening programs for these individuals. In our study, lower sense of coherence, lower perceived social support, poorer quality of sleep, and a higher number of different traumatic events experienced as a victim emerged as the most reliable predictors of the severity of PTSD symptoms in a model that explained 29% of the variance. Within this model, sense of coherence was the strongest predictor (22% explained variance). This finding supports the results of a recent meta-analysis, which reported that sense of coherence explained 17% of the variance in PTSD symptoms after a traumatic event (74). Furthermore, studies by Streb and Schäfer (16, 24) likewise found that sense of coherence was the strongest predictor of PTSD symptoms in German paramedic personnel and other emergency and rescue personnel. In contrast, in the aforementioned study in Swiss mountain guides by Sommer and Ehlert (19), high sense of coherence was found. However, although sense of coherence was a significant predictor, it only explained 1% of the variance of the severity of PTSD symptoms. The authors concluded from this finding that sense of coherence is a factor of mental health rather than a protective factor against PTSD symptoms (19). Contrary to this assumption, Ragger (75) characterized sense of coherence as a protective factor against PTSD symptoms and additionally demonstrated that sense of coherence might positively influence the course of PTSD symptoms. Quality of sleep, perceived social support, and number of different traumatic events as a victim explained only 4, 1, and 1% of the variance, respectively.

Our data revealed perceived stress and sense of coherence to be the most reliable predictors of resilience in a model explaining 25% of the variance. Low perceived stress was the strongest predictor, explaining 19% of the variance, indicating that mountain rescuers who perceived a high level of stress were less resilient. There is evidence that more resilient emergency and rescue personnel experience less stress or are more capable of coping with challenging situations (76, 77). Moreover, it has been proposed that specific training programs to promote resilience might help emergency and rescue personnel to better cope with stress (76). Research also indicates that high resilience protects the individual from developing PTSD at high stress levels (78). In this regard, methods to increase resilience have also been developed and validated specifically for emergency and rescue personnel (79, 80).

In the present study, we found that sense of coherence mediated the association between the severity of PTSD symptoms and resilience, an effect that was also reported by Streb et al. (16) in German paramedic personnel. Moreover, Schnell also identified sense of coherence as a valid predictor of the severity of PTSD symptoms in voluntary firefighters (17). These findings indicate that sense of coherence might be a valuable target for improving resilience as well as for protecting against PTSD symptoms. Research indicates that specific programs are capable of optimizing sense of coherence (25). Indeed, even psychoeducation of emergency and rescue personnel is suitable for elevating sense of coherence (16). Furthermore, a study in Austrian ambulance personnel found that fostering sense of coherence is able to not only preserve general mental health but also improve it (75).

In sum, our results underline the importance of sense of coherence in the field of PTSD psychopathology. Specifically, sense of coherence proved to be a good predictor of PTSD symptoms and mediated the interaction between PTSD symptoms and resilience. Research indicates that sense of coherence might be enhanced by professional interventions, and might therefore be a reasonable target for training and education of rescue personnel (81).

The main limitation of our study is the rather low response rate of 20%, which might have led to systematic error in the sample. One reason for this low response rate might be that more than 50% of the contacted mountain rescuers had not undergone a mission within the last 12 months and were therefore not motivated to take part in the survey. Nevertheless, our sample proved to have captured the more active part (defined as having served at least in one mission in the last year) of the ARS (48% overall vs. 80% test sample). This considerably reduces the risk of underrepresenting traumatic events and consequently PTSD symptoms in the sample. Furthermore, since only self-report questionnaires were used, there is a risk of response bias. Finally, we did not include a scale for social desirability. Although evidence suggests that the tendency for socially desirable responding is strongly reduced in anonymous online surveys, bias in terms of social desirability cannot be definitively ruled out (82). Further research should include clinical interviews and longitudinal designs to address hypotheses regarding causality.

Our results suggest that despite a high prevalence of traumatic events, only a minority of mountain rescuers are burdened with mental health problems or a possible PTSD. We identified sense of coherence as an important predictive factor for the severity of PTSD symptoms and as an effective mediator of the interaction between the severity of PTSD symptoms and resilience. As such, sense of coherence might be a valuable variable for screening and training mountain rescue personnel.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by the Ethics Committee of the Faculty of Arts and Humanities, University of Zurich approved the study. The patients/participants provided their written informed consent to participate in this study.

CM, JS, and UE designed the study. JS conducted the data acquisition and analyzed the data. CM wrote first draft of the manuscript, had full access to all of the data in the study, and took responsibility for the integrity of the data and the accuracy of the data analysis. All authors discussed the findings and edited the final manuscript.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.