Posttraumatic stress disorder (PTSD) is a psychiatric disorder that manifests following the experience of a traumatic event (TE) where the individual has perceived a threat to his or her life or that of others [1]. In France, it is considered to be the third most widespread psychiatric disorder, after major depression and specific phobias. Its prevalence in the European population is estimated to be between 0.7% and 1.9% [2,3]. According to the “dose-response” model, individuals who are most exposed to TEs are most at risk of developing PTSD [3-5]. At-risk occupations, such as the military, law enforcement, and first responders, carry an inherent risk of experiencing trauma. Hence, it is unsurprising to observe a high prevalence of PTSD in military populations, ranging from 10% to 18% or reaching up to 45% [5-9], depending on the study. Although cumulative exposure seems to be an important determinant in the general population [10], the literature does not establish a clear link among at-risk professionals. Nevertheless, it is reasonable to think that cumulative exposure is detrimental, and may even lead to fragilization, which would be consistent with the intensity of PTSD symptoms [11,12]. Repeated exposure triggers a reaction that builds on the consequences of previous exposures, increasing the complexity of the link between cumulative exposure and PTSD development, via multiple pathways.

New medical research has influenced public policy, and the promotion of good health has become a key priority where policies seek to encourage certain behaviors that protect, improve, or restore the health of individuals, groups, or the entire population, while a prevention framework is used when the goal is to limit or prevent the development of a specific disease.

In the 1980s, evidence-based medicine emerged. The approach is founded on the principle of structuring prevention and public health decisions based on scientific evidence (eg, epidemiological studies and systematic clinical studies). A given health problem can be addressed by preventive interventions at primary, secondary, or tertiary levels. The objective of primary prevention is to intervene before the problem occurs; actions target the determinants of the problem by reducing risk factors or by promoting or reinforcing protective factors. In the context of PTSD, primary prevention can intervene at the level of preventing the trauma or at the level of PTSD prevention after the TEs. For at-risk professions in particular, PTSD prevention is the primary target, as the risk of exposure to trauma is integral to the profession. Secondary prevention seeks to define interventions once the problem is identified; it consists of early detection and referral for treatment (ie, after exposure to a TE). Finally, tertiary prevention seeks to manage the problem and prevent relapse. If necessary, the goal is to treat or limit any aggravation of the problem, notably any psychosocial consequences or comorbidities associated with PTSD. At all 3 levels, prevention must respect individual freedom [13].

Effective primary prevention relies upon a sound theoretical understanding of the processes and determinants of the problem, knowledge of actions that have been scientifically validated in other populations, and clinical expertise in the field, which reflects the characteristics (eg, sociocultural) of the target population. This “selective prevention” approach seeks to target exposed participants.

In the domain of PTSD, primary interventions are rare, as such actions aim to prevent the impact of TEs before they occur. Nevertheless, this literature [14] gives us an insight into the potential effects of cumulative exposure to TEs during the career of military professionals. In this context, primary prevention interventions target several determinants that contribute to developing resilience following the TE. The approach underlines the need to characterize the factors that support individual and collective resilience processes, tailored to the characteristics of the population of at-risk professionals. This initial step is a prerequisite to the definition of relevant targets and the development of an appropriate prevention intervention for the population.

The proposed program (which we call Primary Prevention of Posttraumatic Stress Disorder in Military Professionals [PREPAR]) is part of a comprehensive prevention approach that synergistically links physiological, psychological, and social determinants. The approach stems from the etiological model proposed by Jones and Barlow [15]. This model is a comprehensive framework used in clinical psychology to understand the development and maintenance of psychological disorders, particularly PTSD. It integrates various factors that contribute to the onset and perpetuation of these disorders. Several etiological factors, including biological, cognitive, and behavioral components, are implemented in this model. The model also takes into account predisposing factors and moderating variables. It emphasizes a holistic approach to understanding mental disorders, taking into account the complexity of the human experience.

PTSD is described as a failure of emotional extinction which develops following exposure to intense fear. Exposure to a stressful event leads to a neurobiological stress response, resulting in the activation of the sympatho-adrenergic neurovegetative system and the corticotropic neuroendocrine axis. Although this dual physiological response is effective in the short term, it comes with a biological cost; regulatory mechanisms aim to compensate for this loss by supporting poststress recovery. A repeated inability to recover and extinguish the stress response in the long term (repeated exposures over a short time period) creates a so-called “allostatic load” [16], which progressively limits the flexibility of the central and peripheral nervous system. The peripheral nervous system is of particular interest, due to its role as a mediator of the allostatic load. The parasympathetic branch plays a role in the emotional extinction and correction of the load, making it a key vulnerability factor for health when it is insufficiently effective [17]. Certain professions (frontline responders and military personnel) are at risk of developing a significant allostatic load, due to their repeated exposure to TEs (inherent in the nature of their work). On top of this, personnel must adapt, on a daily basis, to various environmental demands: physiological (sleep debt, altered sleeping patterns, etc), physical (hypoxia, etc), and cognitive and emotional (traumatic exposure, etc), among others. All of these factors test the flexibility of the individual’s physiological systems, particularly the autonomic (ie, parasympathetic) nervous system, which, consequently, appears to be a key target for prevention measures.

Military personnel participate in multiple missions in conflict zones, and this is likely to alter the flexibility of their executive and emotional regulation functions. Although training programs aim to develop automated responses to well-known mission scenarios, they do not focus on developing the change in viewpoint that contributes to the resilience process. Moreover, preclinical data show that both acute and repeated stress are likely to reduce cognitive flexibility [18,19]. A slight reduction in cognitive flexibility likely reduces the flexibility of emotional regulation strategies following a TE, thus increasing the impact of exposure. This hypothesis draws upon the notion of “coping flexibility.” The latter concept represents the individual’s ability to evaluate the effectiveness of his or her strategies for coping with stress in a specific situation and then adopting alternative strategies, if necessary [20]. The evaluation of training in the diversification of emotional regulation strategies in military populations has found a reduced risk of PTSD after exposure to TEs. Furthermore, a relationship has been identified between cognitive flexibility and self-compassion [21]. The data also suggest that increasing self-compassion contributes to increasing cognitive flexibility [22].

Finally, a clear sense of duty has been found to counterbalance perceived constraints associated with the mission [23,24]. The literature reports that the meaning attributed to the work environment can, to a significant degree, compensate for the perception and impact of occupational stressors [25].

The social dimension targets normative pressure and stigmatization. These determinants are specific to the institutional context of military personnel and may represent risk factors. Thus, normative group pressure to follow codes that encourage the nonexpression of emotions [26] can be a risk factor, as military personnel can be reluctant to speak about their psychological and somatic symptoms, which delays treatment. A fear of stigmatization by the institution and peers is another potential barrier to care. Overall, these social factors are obstacles to both individual and collective positive health behaviors.

The goal of this project is to evaluate a multidimensional biopsychosocial primary prevention intervention for PTSD aimed at strengthening the resilience of at-risk professionals, namely military personnel, in order to prevent the occurrence of PTSD or reduce its severity.

The objectives of the project are as follows: (1) to design a primary prevention program for PTSD specific to the studied military population and compatible with operational constraints; (2) to implement or validate the program with operational personnel belonging to the French Mountain Infantry Brigade (Brigade d’Infanterie de Montagne); and (3) to understand PTSD and its prevention from 3 perspectives: biophysiological (by studying key markers of the neurobiological stress response, strain and vulnerability and increasing the flexibility of the autonomic nervous system); psychological (by facilitating and measuring the development of flexible strategies to cope with stress and evaluating the moderating role of the meaning of the mission in the development of PTSD); and social (by facilitating community strategies aimed at reducing stigmatization and helping professionals in difficulty to access care in the institutional context).

Our biopsychosocial approach adopts an integrative understanding of the processes at play in the risk of developing PTSD. This perspective makes it possible to target levers related to factors specific to the individual (at physiological and psychological levels), and contextual and social factors (related to the working environment).

The change in parasympathetic vagal flexibility is an early and silent sign of physiological deterioration. It can be identified by noninvasive measurements (resting or tonic heart rate variability, and activation or phasic heart rate variability) and modulated by exercises that target vagal activity (cardiac coherence techniques), which can be easily integrated into a busy professional agenda. A preliminary feasibility study among a group of firefighters (SDIS 73) demonstrated very good acceptance of this technique by the selected professionals and good adoption in daily life [24].

Two factors are targeted in the psychological dimension: coping flexibility and the sense of duty. These 2 determinants have rarely been targeted in studies of the prevention of occupational PTSD. The focus on coping flexibility and self-compassion seeks to improve emotional regulation, and the focus on the sense of duty seeks to target the silent determinants of occupational PTSD, with the overall aim of identifying an effective primary prevention intervention.

The targeted determinants are the beliefs and socio-normative processes that play a role in PTSD in a military population (self-stigmatization, stigmatization by others, normative pressure, and group cohesion). The intervention aims to establish a dedicated space to normalize the discourse, with the overall aim of discussing PTSD and making it visible, along with the signs of emerging psychological and somatic injuries. Specific group facilitation techniques are used, notably social modeling, which aims to reinforce feelings of self-efficacy that support the public expression of signs of injury and to support the search for appropriate care, when necessary [27].

There is no consensus in the literature regarding the definition of resilience, and there are references to several dimensions. Consequently, measuring the effect of the intervention on resilience requires the use of several indicators. A simple approach would be to measure PTSD symptomatology reported by participants, with the expectation that the intervention will result in a decrease in symptoms. Although this approach would be relevant for long-term measures [40], using this criterion in a short-term study, such as ours, would be restrictive and fail to support the processes that are assumed to be activated during the intervention [41]. The latter consists, in part, of removing barriers to seeking care when necessary, in order to support the building of resilience as a process, and not simply as a state. Our short-term approach is also justified by the difficulty of conducting studies in a military environment over the long term (personnel are transferred every 3 years) and attrition among professional soldiers.

The proposed composite criterion groups indicators of resilience that are described as protective factors for PTSD and are recognized to be sensitive to interventions. The first is the participant’s emotional state. It is known to be highly impacted in PTSD, where there is an increase in negative emotions. At the same time, it is a marker of resilience in cases where emotions become positive following trauma. We will therefore use the Positive and Negative Affect Scale (PANAS) score [42], which measures the intensity of positive and negative emotional states. Our second indicator measures self-compassion, which refers to a general tendency to be kind to oneself, despite knowing one’s failures and successes. Self-compassion is very directly linked to the process of self-acceptance and is a predictive criterion for both the development of PTSD (when it is deficient), and increased resilience (when stimulated by a psychotherapeutic intervention). Self-compassion also contributes to cognitive flexibility. Finally, the third indicator is the hardiness score. This measure is classically used in the literature to study, from a psychological point of view, an individual’s ability to remain in good health under stressful conditions. It should be noted that this measure should not, by itself, be considered a sufficient criterion for resilience in our protocol, given that any modification is observed over the long term, based on a quasi-dispositional approach.

Consequently, the hardiness score will be combined with mood and self-compassion criteria. The composite criterion will be evaluated at 4 months (Figure 1). A change in resilience will be defined as favorable if at least two of the following three criteria are met: (1) a 20% improvement in the PANAS score; (2) given the military context, and the nonspecific nature of our intervention, a 20% improvement in scores on the Self-Compassion Scale; or (3) a 5% change in hardiness, measured using the Dispositional Resilience Scale (DRS-15) [43]. If these criteria are not met, any change will be considered to be unfavorable. The choice of thresholds for variables making up the composite criterion is based on data from research conducted by the project’s teams.

The data based on the STEP study, carried out in the framework of Delphine Traber’s thesis [24], show a 33.68% long-term increase in the PANAS score among members of the Bataillon de Chasseurs Alpins who had undergone training (pretraining score=12.32, posttraining score=15.21, and 6-month posttraining score=16.47). Thus, in the PREPAR study, we consider a 20% improvement as significant (for questionnaire details, see Multimedia Appendix 2 [42-44]).

According to Kotsou and Leys [44], the mean score is 2.88 in the French population. A score between 3.5 and 5.0 indicates a high level. Thus, in the context of this study, an increase of 20% (0.62) will be considered relevant (for questionnaire details see Multimedia Appendix 2).

In the literature, global hardiness scores (measured by the DRS-15 scale) in military populations are around 29 (scores can range from 0 to 45). To the best of our knowledge, there are no studies that have evaluated the effect of a prevention program on this variable. Thus, as this is a dispositional measure, we consider a 5% increase as relevant (for questionnaire details see Multimedia Appendix 2).

We will assess the following regarding vulnerability:

We will assess follow-up of the change in scores on composite end point questionnaires: PANAS, Self-Compassion Scale, and DRS-15 at 6 and 12 months after inclusion.

We will assess the following regarding change in physiobiological biomarkers of activation and deterioration:

We will assess the following regarding change in psychosocial factors:

Adherence will be assessed using quantitative criteria at 4, 6, and 12 months (the Treatment Motivation Questionnaire). This analysis will be based on (1) an analysis of the processes put in place to operationalize the intervention; (2) a focus group consisting of 8 participants, and 10 individual interviews carried out at 4 and 12 months after inclusion; and (3) a qualitative analysis of discussions that took place during workshops to anchor the practice held at 6 months and 1 year. The latter will also make it possible to identify both obstacles and drivers of adherence.

We will assess user satisfaction with the URGOfeel (Urgothech) application using visual analog scales, and short questionnaires that measure (1) the user experience and (2) its benefits.