In this study, we tried to detect new possibilities to improve the working conditions for voluntary and full-time ambulance personnel. To that end, we examined the impact of SOC on PTSS and PTG in Austrian ambulance personnel. We hypothesized that PTG and PTSS were related to SOC but also existed independently from one another. Therefore, SOC might be linked to PTG despite the possible presence of PTSS.
Regarding the relationships between SOC, PTG and PTSS our findings concur with already existing literature in this particular field of research [12, 21, 22, 26, 27]: Higher levels of SOC are associated with higher levels of PTG as well as with lower levels in the PTSS-domains Avoidance and PTSD-Probability in Austrian ambulance personnel.
Additionally, we found indications that a higher level of SOC seems to increase the probability for the development of PTG in Austrian ambulance personnel after the experience of critical incidents in the line of duty. Notably, we found positive associations between the SOC-subscale Meaningfulness and the PTG Total Score (r = .27, p < .01) plus the PTG-subscales New Possibilities (r = .27, p < .01), Relating to Others (r = .31, p < .01) and Appreciation of Life (r = .14, p < .05). Maybe, those findings underline the relevance of SOC and the possible significant role of the SOC-subscale Meaningfulness for the development of PTG after experiencing a critical incident. Possibly, an explanation for this could be found through the assumption that people who are in general quite capable in finding more meaningfulness in their life (SOC-dimension) should therefore also be quite capable in finding more meaningfulness in a distressing life event [19,20,21]. In addition, this ability to find meaningfulness is assumed to grow while struggling with the distressing life event; this struggle is also seen as essential for the development of PTG later on in the adjustment process . Therefore, ambulance personnel might be especially capable of finding meaningfulness in distressing life events because of the constant struggle with such events in the line of duty. Subsequently, this constant struggle could have a beneficial effect for the development of PTG later on. Concerning this, Linley and Joseph  found indications that an enhanced SOC seems to predict PTG in psychotherapists who are also often confronted with distressing events. Furthermore, a study by Triplett et al.  found a positive relationship between the existence of meaningfulness in a person’s life and PTG.
However, the majority of published studies so far regarding the relationship between SOC and PTG mostly highlight the role of the SOC-dimension meaningfulness for the development of PTG. Yet, some studies could be found, who concentrate on the SOC-construct as a whole or on the remaining SOC-dimensions comprehensibility or manageability. In this context, a study by Arya and Davidson  should be mentioned in particular, because they found indications for a positive association between the SOC-construct as a whole and the PTG total score. Furthermore, they also detected positive relationships between all the three SOC-dimensions comprehensibility, manageability and meaningfulness and the PTG-dimensions Relating to Others, Spiritual Change and the PTG total score. Moreover, Nishi et al.  found positive relationships between all three SOC-dimensions and the PTG-dimensions “Personal Strength” as well as “Relating to Others” in a sample of accident survivors. Furthermore, a study by Kennedy et al.  regarding patients in rehabilitation after a spinal cord injury, could prove a relationship between the SOC-dimension manageability and stress related growth. Furthermore, it should also be pointed out that some studies found indications for a negative relationship between SOC and PTG. Concerning this, a study by Brockhouse et al.  revealed a negative relationship between a lower SOC and a higher level of PTG. Also, there could be some studies found, which either reported a positive relationship between SOC and PTG or no significant relationship at all [40, 45]. On that account, future studies should concentrate their focus in particular on the relationships between the SOC- and PTG-dimensions for a more thorough and detailed examination of this topic.
Regarding ambulance personnel, a further possible reason for the found link between SOC and the development of PTG after critical incidents might be the already implemented peer support system in the Austrian Red Cross [46, 47]. More specifically, this peer support system consists of specially trained ambulance officers who provide psychological support for colleagues after they have experienced a distressing event in the line of duty. As a result, the supported ambulance personnel increases their ability to reduce their stress level and to regain their operational ability . Furthermore, this peer support is likely to enhance the confidence of the supported ambulance officers to handle their job-related duties further on (SOC-dimension manageability) and to find a deeper meaning in the experience of the distressing incident (SOC-dimension meaningfulness) [19,20,21].
Concerning this, as previously mentioned, we found positive associations between the SOC-subscale Meaningfulness and the PTG-subscales New Possibilities, Relating to Others, Appreciation of Life plus the PTG Total Score. Perhaps, ambulance personnel might profit from an incorporation of this study results in the peer support system of the Austrian Red Cross. In detail, members of this support system could receive further training to promote SOC among their colleagues (e.g. to encourage their colleagues in finding a deeper meaning out of a distressing event which was experienced in the line of duty). As a consequence, the peers could become more competent in promoting the constructs of SOC and PTG among Austrian ambulance personnel, whereby their readiness for duty and the possibility for the development of PTG after experiencing a distressing incident might be increased. Supporting this, a study by Linley, Joseph and Loumidis  assumed, that the construct of SOC could promote positive adaption processes after traumatic experiences (e.g. PTG).
In contrast, it could also be possible that the implemented peer support system could have negative effects. In literature it is theorized, that the premature addressing of distressing experiences (e.g. during the course of a peer support session) could enhance the risk of experiencing a renewed loss of control over the distressing situation as well as the risk of experiencing an overflow through intrusive memories . As a consequence, this overflow could enhance trauma related intrusions as well as avoidance behaviour and therefore, complicate the overcoming of distressing experiences .
The generally high level of SOC in Austrian ambulance personnel might also be attributed to the professional preparedness through their ongoing training, including expert knowledge regarding the management of medical emergencies. Acquiring additional psychological knowledge (e.g., through psychoeducation as part of the training) could also facilitate the ability to find meaningfulness in a distressing event. This theory is supported by Streb  and Langeland et al.  who found that ambulance personnel with professional training showed a higher SOC-level and a lower PTSS-level than non-prepared colleagues. Furthermore, the availability of psychological support also leads to higher SOC-levels and lower PTSS-levels [12, 25]. Further studies will be needed to determine whether an increase in professional training and psychological interventions might be able to further increase the SOC-level and lower the PTSS-level in Austrian ambulance personnel.
Compared to other professions, ambulance personnel might be generally more likely to develop PTG if confrontation with fundamental existential topics (e.g. the meaning of life or the possibility of afterlife) is an integral part of their daily duties. For instance, resuscitating a patient after a heart attack could possibly lead to more intense thoughts about their own mortality. Subsequently, this could be followed by the development of a deepened meaning of spirituality or an increased appreciation of life, all well known as dimensions of PTG [13, 16]. Concerning this, our sample showed similar PTG total scores (M = 43.38, SD = 15.03) than firefighters  (M = 42.75, SD = 22.12). However, our sample also showed higher PTG total scores when compared to people who did not work in these professions but had experienced traumatic events in their private lives – for example a sample of men with prostate cancer (M = 38.37, SD = 26.64) in a study by Walsh et al.  as well as a sample of head and neck cancer survivors (M = 30.80, SD = 19.70) in a study by Holtmaat et al. .
Additionally, the results of the cluster analysis included a cluster (Cluster C) which consisted of ambulance personnel who showed high PTSS-levels as well as high PTG-levels. This underlines the hypothesis of Tedeschi and Calhoun  that PTSS and PTG represent independent constructs which could be present at the same time as the memory of the event itself could remain distressingly separate from experience of growth [13, 15, 16]. Potentially, the combination of professional training and being confronted with extremely distressing events – including incidents with many dead or severely wounded people, a dead or severely wounded child or colleague, a strong personal identification with the victims, mortal danger and extreme interest of the media  – is particularly likely to elicit both PTG and PTSS.
However, further studies are required to investigate possible differences in developing PTG after experiencing a distressing event in the line of duty in addition to the potential beneficial effects of SOC on PTG in voluntary and full-time Austrian ambulance personnel. Up to this point, it also remains unclear whether there are differences between voluntary and full-time ambulance personnel in the extent of regular confrontation with distressing events and in the regeneration from it.
Moreover, the results of this study can only be interpreted with simultaneous consideration of potential limitations. Since the current study concentrated on Austrian ambulance personnel the results might not be comparable to studies from other countries with different concepts of professional education and training. For example, a study by Pohl-Meuthen et al.  showed significant differences among European ambulance services regarding organization, infrastructure, occupational qualification, duration of training and the level of medical qualification. However, the consideration of voluntary ambulance personnel can be seen as a strength of the present study because, as far as we know, no other studies have addressed PTSS and PTG in voluntary ambulance personnel. Nonetheless, volunteers play a crucial role in the effective functioning of the Austrian emergency services (ambulance and fire service). In addition, while positive psychological changes after traumatic incidents (e.g. PTG) have become an important factor for the professional treatment of post-traumatic stress disorders, there is still some debate on the definition and measurement of PTG in research : Previous insights on this subject rest upon the results of cross-sectional studies, mostly using the PTGI  as a retrospective measurement of self-reported growth after traumatic incidents. Thus, the participants are instructed to recall their inner mental state prior to a traumatic event in retrospect and subsequently evaluate the extent of positive change after the event happened . This could be quite a challenging psychological task which may never have happened spontaneously on its own. Indeed, this circumstance could have thoroughly influenced the given PTGI answers substantially . Furthermore, regarding the symptoms of Post-Traumatic Stress (PTSS), it should be noted that in our current study no PTSD diagnosis were assigned. While the IES-R [29, 30] is a reliable tool for the self-assessment of the three major DSM-IV-TR criteria for Post-Traumatic Stress - Intrusion, Avoidance and Hyperarousal [7, 31, 32] – it is not sufficient for diagnosing PTSD. Moreover, the present study found a significant, though small, correlation between SOC and PTG (r = .27; p < .01) which could be an indication for a possible link between SOC and PTG. However, because this study was designed as a cross-sectional study and did not compare SOC with another traits, it is not justified to say that our findings point to SOC playing an important role in the development of PTG after the experience of critical incidents. For this purpose, it is necessary for future studies to use a longitudinal study design to examine possible facilitating influences of SOC on PTG.