Anaïs Madamet

Catherine Potard
email: catherine.potard@univ-angers.fr

Isabelle Huart
email: isabelle.huart@univ-tours.fr

Wissam El-Hage
email: wissam.elhage@univ-tours.fr

Robert Courtois
email: robert.courtois@univ-tours.fr

Relationship between the Big Five personality traits and PTSD among French police officers Liens entre les cinq grands facteurs de personnalité et le SSPT chez des policiers Français

Keywords: Posttraumatic stress symptoms, Big Five personality factors, Personality profile, Work-related stress, Police personnel

Personality and PTSD symptoms in police 1

Relationship between the Big Five personality traits and PTSD among French police officers

Liens entre les cinq grands facteurs de personnalité et le TSPT chez des policiers

Résumé

Introduction : Le trouble de stress post-traumatique (TSPT) est rare parmi les policiers, mais les symptômes ne le sont pas. Les traits de personnalité peuvent être un facteur médiateur des troubles liés au stress. Ils permettent habituellement d'identifier trois profils de personnalité : les « résilients » caractérisés par une forte stabilité émotionnelle, des compétences sociales et une confiance en soi élevées ; les « sur-contrôlés » qui ont des scores élevés de Névrosisme et une tendance à internaliser leurs émotions négatives et des « sous-contrôlés » avec un faible Caractère consciencieux (impulsivité), une tendance à l'isolement social et une faible estime de soi.

Objectif : L'objectif de cette étude était d'examiner le rôle de la personnalité dans l'apparition de symptômes du TSPT chez les policiers français.

Méthode : Les participants étaient des policiers français (N=100, M = 32,9 ans, ET = 9,8, 19-57) qui ont complété l'échelle de l'état de stress post-traumatique (PCLS) et l'inventaire des cinq grands facteurs de personnalité (BFI).

Résultats : Les résultats ont retrouvé les trois profils de personnalité attendus : « résilients » (n=31), « sur-contrôlés » (n=43) et « sous-contrôlés » (n=19). Les premiers présentaient le moins de symptômes de TSPT et les derniers le plus (en particulier la répétition ou intrusion).

Ils avaient également les scores les plus élevés de Névrosisme et les plus bas d'Extraversion et d'Agréabilité. Ces policiers étaient aussi les plus âgés ou ceux qui avaient servi le plus longtemps dans la police. Le Névrosisme et la durée du service étaient les deux facteurs prédictifs des symptômes de TSPT pour la répétition et l'évitement.

Conclusion :

Cette étude met en évidence la contribution de chaque trait de personnalité et durée de service pour les symptômes de TSPT chez les policiers français.

Mots-clés: Symptômes de stress post-traumatique ; Cinq grands facteurs de personnalité ; Profil de personnalité ; Stress lié au travail ; Police.

Relationship between the Big Five personality traits and PTSD among

French police officers

Introduction

Several studies have shown that police work is particularly stressful (e.g. [START_REF] Aytac | The sources of stress, the symptoms of stress and anger styles as a psychosocial risk at occupational health and safety: A case study on turkish police officers[END_REF][START_REF] Lau | Personality types, coping, and stress in the Norwegian police service[END_REF]. Stress is related both to critical events, which are rare, and to everyday working conditions and the way that police officers cope with the pressures they face. Exposure to critical events (sexual trauma and combat trauma) is more predictive of posttraumatic stress disorder (PTSD) than other trauma types [START_REF] Habersaat | Health in police officers: Role of risk factor clusters and police divisions[END_REF][START_REF] Jakob | The impact of trauma type or number of traumatic events on ptsd diagnosis and symptom severity in treatment seeking veterans[END_REF]. About 4.5% to 9% of police officers may suffer from full PTSD [START_REF] Berger | Rescuers at risk: A systematic review and meta-regression analysis of the worldwide current prevalence and correlates of PTSD in rescue workers[END_REF][START_REF] Maia | Post-traumatic stress symptoms in an elite unit of Brazilian police officers: Prevalence and impact on psychosocial functioning and on physical and mental health[END_REF], but nearly 15-16% suffer from partial PTSD [START_REF] Maia | Post-traumatic stress symptoms in an elite unit of Brazilian police officers: Prevalence and impact on psychosocial functioning and on physical and mental health[END_REF][START_REF] Marmar | Predictors of Posttraumatic Stress in Police and Other First Responders[END_REF].

Work stressors and managing the job can cause other mood disorders in police officers, such as burnout [START_REF] Kula | Occupational stress, supervisor support, job satisfaction, and work-related burnout: Perceptions of Turkish National Police (TNP) members[END_REF][START_REF] Lau | Personality types, coping, and stress in the Norwegian police service[END_REF], which are also underpinned by individual vulnerability factors [START_REF] El Hage | Vulnerability to depression: What is the role of stress genes in gene × environment interaction[END_REF]. Understanding the protective factors against developing PTSD symptoms or other stress-related disorders is a major public health priority, and yet there have been few studies on protective or aggravating factors [START_REF] Ellrich | Post-traumatic stress symptoms in police officers following violent assaults[END_REF].

The Big Five personality model (Five-Factor Model or FFM) is the most consensual approach to personality assessment. It proposes five main dimensions of personality, broadly defined as Extraversion vs. Introversion, Agreeableness vs. Antagonism, Conscientiousness or Control vs. Impulsivity, Neuroticism vs. Emotional Stability, and Openness to New Experience/Intellect vs. Closed-mindedness [START_REF] John | Paradigm shift to the integrative big-five trait taxonomy: History, measurement, and conceptual issues[END_REF][START_REF] John | The big five trait taxonomy: History, measurement, and theoretical perspectives[END_REF]. Extraverted people are outgoing, sociable with positive emotionality, talkative, energetic, assertive, and excitement seeking. Agreeable individuals promote prosocial and communal orientation toward others, they are cooperative, friendly, considerate or empathic, generous, trustful, and kind. Conscientious individuals facilitate goal-directed and planned behavior, they are work-oriented, responsible, attentive, careful, dependable, persistent, orderly, and impulse controlled. Neuroticism is associated with anxiety and instability. Neurotic individuals are moody, angry, easily frustrated, lacking in confidence, insecure in relationships, and sometimes anti-social. Individuals high in Openness are imaginative, curious, creative, complex and subtle, with artistic values, unusual ideas, and varied experiences. They are also quick to learn, clever, insightful, and independent-minded [START_REF] Caspi | Personality development: stability and change[END_REF][START_REF] John | Paradigm shift to the integrative big-five trait taxonomy: History, measurement, and conceptual issues[END_REF].

To understand and prevent mood disorders among police officers, it is important to gain a deeper insight into personality traits that may be linked to PTSD symptoms. Police officers probably share common personality traits [START_REF] Lau | Personality types, coping, and stress in the Norwegian police service[END_REF][START_REF] Lorr | Personality profiles of police candidates[END_REF], although some authors doubt the idea of a single profile [START_REF] Wagner | The "Rescue Personality": Fact or fiction?[END_REF]. The personality profile of police officers is likely to be characterized by low scores on Neuroticism (i.e., emotionally secure), high scores on Extraversion (i.e., more assertive and self-confident), high scores on Conscientiousness (i.e., with a strong pattern of self-discipline or sense of control), and high scores on Agreeableness (i.e., friendly, sociable and gregarious) (e.g. [START_REF] Lau | Personality types, coping, and stress in the Norwegian police service[END_REF][START_REF] Lorr | Personality profiles of police candidates[END_REF][START_REF] Wearing | Work and non-work coping strategies: their relation to personality, appraisal and life domain[END_REF]. This suggests the existence of a "Rescue Personality" of police officers and firefighters [START_REF] Mitchell | Emergency services stress: Guidelines for preserving the health and careers of emergency services personnel[END_REF]. Similar results have been found with other personality assessment tools (e.g. Eysenck: highly extraverted, venturesome and impulsive, but conforming, [START_REF] Gudjonsson | Personality patterns of British police officers[END_REF].

Obviously, personality factors could represent a mediating factor between environmental stressors and mental health. For instance, several studies highlighted the role of Neuroticism (low Emotional stability) in perceived stress levels and stress reactivity (e.g. [START_REF] Garbarino | Personality traits of the five-factor model are associated with work-related stress in special force police officers[END_REF][START_REF] Heinrichs | Predicting posttraumatic stress symptoms from pretraumatic risk factors: A 2-year prospective follow-up study in firefighters[END_REF][START_REF] Jakšić | The role of personality traits in posttraumatic stress disorder (PTSD)[END_REF][START_REF] Vollrath | Personality and stress[END_REF][START_REF] Yuan | Protective factors for posttraumatic stress disorder symptoms in a prospective study of police officers[END_REF]. Neuroticism fosters the subjective experience of negative emotions of events. By contrast, Extraversion and Agreeableness are both related to more positive feelings, and better adaptation to stressful work (e.g. [START_REF] Garbarino | Personality traits of the five-factor model are associated with work-related stress in special force police officers[END_REF][START_REF] Jakšić | The role of personality traits in posttraumatic stress disorder (PTSD)[END_REF][START_REF] Skomorovsky | Psychological well-being of Canadian forces officer candidates: The role of personality and coping strategies[END_REF]. Three personality profiles were described by [START_REF] Block | Lives through time[END_REF] using the Q-Sort Method for personality assessment: Resilients, Overcontrollers, and Undercontrollers. These profiles were consistent and stable over time. Various subsequent studies on children or adults found similar results. Subsequently, they were also found using the Big Five personality traits (e.g. [START_REF] Asendorpf | Carving personality description at its joints: Confirmation of three replicable personality prototypes for both children and adults[END_REF][START_REF] Asendorpf | Resilient, overcontrolled, and undercontroleed personality prototypes in childhood: Replicability, predictive power, and the trait-type issue[END_REF][START_REF] Boehm | Replicable types and subtypes of personality: Spanish NEO-PI samples[END_REF][START_REF] Robins | Resilient, overcontrolled, and undercontrolled boys: Three replicable personality types[END_REF]. Across studies, Resilients obtain the most favorable descriptions on all five scales (high emotional stability and high scores in the other four personality traits). They demonstrate high social skills and self-confidence. They do not have mental disorders, and they succeed academically and socially. Overcontrollers score higher on Neuroticism than Resilients, associated with high Agreeableness and low Extraversion. They share some of the features of Resilients, but tend to internalize their problems and negative emotions. Undercontrollers are characterized by low Conscientiousness (impulsivity) and low Agreeableness, with a tendency toward social withdrawal and low self-esteem. They tend to fail academically and socially and have more emotional and behavioral problems.

Personality traits can thus constitute protective factors against stress and mood disorders, or, on the contrary, they can increase susceptibility to psychic morbidity and anxiety disorders. The aim of this study was to examine the role of personality traits and profiles in the emergence of PTSD symptoms among police officers. We expected to observe that police officers with Resilient characteristics would show the fewest PTSD symptoms and those with features of Undercontrollers would show the most.

Material and methods

Participants and procedure

Participants were recruited in a French national police training center. All the police officers who were contacted agreed to participate in the study. After they had been informed of the aims of the study, they gave their informed consent, and completed the paper self-report questionnaire anonymously. Clear and precise instructions were given, and the importance of giving honest answers was stressed. No incentive was provided. This study complies with the Code of Ethics of the World Medical Association (Declaration of Helsinki).

Our sample comprised 100 French national police officers (M = 32.9 years, SD = 9.8, 19-57), including 28 women (27.7%); 58 (58%) were patrolmen (gardiens de la paix) or judicial police officers (officiers de police judiciaire), 41 (41%) were auxiliary police officers, and 1 (1%) was a forensic technician (technicien de la police scientifique). Participants were selected consecutively for inclusion in our sample, in close contact with the police districts in the 'Centre-Val de Loire' Region (France). Average length of service in the police force was 10.9 years (SD = 9.9, 0-34), 12.2 years (SD = 9.2, 0-34) for men and 7.7 years (SD = 9.3, 0-30) for women. The median was respectively 10.0, 12.0, and 2.5 years. Eight participants were excluded due to incomplete questionnaires.

Instruments

PCLS. The Posttraumatic Stress Disorder Checklist Scale [START_REF] Ventureyra | The validation of the Posttraumatic Stress Disorder Checklist Scale in posttraumatic stress disorder and nonclinical subjects[END_REF]Weathers, Litz, Herman, Huska, & Keane, 1993) is a brief and practical self-report assessment of the severity of PTSD-related symptoms of intrusion/reexperiencing, avoidance/numbing, and hyperarousal (DSM-IV symptom criteria) in the past month. The 17 items are rated on a 5-point scale (from 1 -not at all -to 5 -extremely); total score is the sum of all 17 items. Participants report the level of distress experienced for each item. The total score can be divided into 3 sub-scores: reexperiencing (items 1-5), avoidance (items 6-12), and hyperarousal (items 13-17). Scores range from 17 to 85, with higher scores indicating greater severity of PTSD symptoms. A cutoff score of 44 has demonstrated high diagnostic accuracy for PTSD (.97), with good specificity (.87) and sensitivity (.94) [START_REF] Ventureyra | The validation of the Posttraumatic Stress Disorder Checklist Scale in posttraumatic stress disorder and nonclinical subjects[END_REF].

BFI.

The Big Five Inventory [START_REF] John | The Big Five Inventory--Versions 4a and 54[END_REF][START_REF] Plaisant | Relations entre le Big Five Inventory français et le manuel diagnostique des troubles mentaux dans un échantillon clinique français [Relations between the French version of the Big Five Inventory and the DSM classification in a French clinical sample of psychiatric disorders[END_REF]) is a self-administered questionnaire containing 45 items for five dimensions: Extraversion, Agreeableness, Conscientiousness, Neuroticism and Openness to experience. Participants answer on a Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). The BFI has good psychometric properties.

Data analysis

Internal consistency of the dimensions of the Big Five Inventory, as assessed by Cronbach's alpha coefficient, was > .70. We conducted a k-means cluster analysis, which allocates each case to the cluster with the nearest center point. To compare clusters (personality prototypes), we used analysis of variance (ANOVA), with post hoc comparisons (Bonferroni test) to assess the differences between groups (group interactions). Next, we calculated Bravais Pearson's correlations to evaluate the relationship between PTSD symptoms and personality traits. Next, we conducted a multiple regression analysis to determine the relative weights of length of service and Big Five personality traits on the PTSD symptoms. Finally, Structural Equation Modeling (SEM) was performed using the maximum likelihood estimation. In this study, selected values were greater than 0.90 for the comparative fit index (CFI) and the Normed Fit Index (NFI), less than 0.08 for the root meansquare error of approximation (RMSEA), and less than 3 for the χ2/df [START_REF] Arbuckle | AMOS (Version 5.0)[END_REF][START_REF] Byrne | Structural Equation Modeling with AMOS: Basic concepts, Applications, and Programming[END_REF][START_REF] Hu | Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives[END_REF]). An alpha level of less than 5% was considered statistically significant. Statistical analyses were performed with Statistica® and AMOS®.

Results

Descriptive statistics of PTSD symptoms and the BFI scores are provided in Table 1, including Cronbach's alpha coefficient. Based on the cut-off score of 44 on the PCLS, 3 police officers (3.2%) had a very probable diagnosis of PTSD. Based on the broader cut-off score of 34 on the PCLS, 12 police officers (12.9%) were affected by partial PTSD. Using a diagnostic approach based on DSM-IV criteria, with at least 1 item reported for Reexperiencing (with a score ≥3), associated with three or more items for Avoidance, and at least 2 items for Hyperarousal, 4 police officers (4.3%) met the criteria for PTSD diagnosis.

These 4 police officers were male (M = 37.5 years, SD = 8.5, 27-47), had been working for a long time in the police (M = 15.8 years, SD = 8.2, 8-27), and had high PTSD total severity scores (M = 45.5, SD = 6.3, 39-54) (with high sub-scores for Reexperiencing (M = 14.0, SD = 3.9, 10-19), Avoidance (M = 16.2, SD = 1.3, 15-18), and Hyperarousal (M = 15.2, SD = 5.3, 11-23)).

- -----------------------------------------------------------------------------------------------------Please Insert Table 1 here - -----------------------------------------------------------------------------------------------------Next, we conducted a k-means cluster analysis, which divided the police officers into three clusters according to personality prototypes [START_REF] Asendorpf | Carving personality description at its joints: Confirmation of three replicable personality prototypes for both children and adults[END_REF][START_REF] Block | Lives through time[END_REF]. BFI scores yielded the three expected personality types: Resilients, Overcontrollers and Undercontrollers (Figure 1). The Resilients had the most positive personality traits, with high scores on Extraversion, Agreeableness, Conscientiousness, and Openness, and low scores on Neuroticism (high emotional stability). The Overcontrollers had a similar but less positive profile, while the Undercontrollers had high scores on Neuroticism and low scores on Conscientiousness (impulsivity). The Resilients group (n = 31) comprised 58.1% men, young adults (M = 27.5 years, SD = 7.9, 20-57), with the shortest length of service in the police (M = 5.2, SD = 6.5 years, 2-30). The Overcontrollers group (n = 43) was composed predominantly of men (81.4%), young adults (M = 33.0 years, SD = 9.6, 19-52), with longer service (M = 10.9 years, SD = 9.0, 0-31). The Undercontrollers group (n = 19) was composed of 73.7% men, who were older (M = 38.3 years, SD = 8.9, 20-51) and had spent the longest time in the police (M = 16.9 years, SD = 8.6, 1-32).

- -----------------------------------------------------------------------------------------------------Please Insert Figure 1 and Table 2 here - -----------------------------------------------------------------------------------------------------Between these three groups, differences in the BFI scores were significant for all traits (Table 2). Post hoc comparisons (Bonferroni test) were performed to assess the differences between groups (group interactions). Next, we compared PTSD symptoms according to personality profile (Figure 2). These symptoms were greater in the Undercontrollers than in the Resilients and Overcontrollers. All differences between groups are shown in Table 3, including Post hoc comparisons (Bonferroni test).

- -----------------------------------------------------------------------------------------------------Please Insert Figure 2 and Table 3 here ------------------------------------------------------------------------------------------------------Undercontrollers had higher scores on Neuroticism, and lower scores on Conscientiousness and Agreeableness than Resilients and Overcontrollers. They also had more symptoms of PTSD (Reexperiencing, Avoidance, and Hyperarousal) than the other personality profiles. They were the oldest police officers, or those who had worked the longest in the police. The correlation between age and length of service was high (.97, p <.001). Therefore, we looked for links between PTSD symptoms (related to reexperiencing, avoidance, or hyperarousal), length of service, and personality traits. Table 4 shows correlations between PTSD symptoms and length of service (respectively .55, .41 and .26, p < .001).

- -----------------------------------------------------------------------------------------------------Please Insert Table 4 here - -----------------------------------------------------------------------------------------------------Next, we carried out a step-by-step multiple regression analysis to determine the relative weights of length of service, Extraversion, Agreeableness, Conscientiousness, Neuroticism and Openness on the PTSD symptoms, starting with Reexperiencing. They explained 42% of the variance (p < .001), with length of service, which made up the first step, contributing 31% (p < .001), followed by Neuroticism bringing about 11% of additional variance (p < .001). We carried out the same procedure for Avoidance. The same independent variables explained 28% of the variance (p < .001), with Neuroticism accounting for 21% (p < .001) and length of service 7% (p < .01). Finally, we carried out the same procedure for Hyperarousal. Only Neuroticism explained more than 18% of the variance (p < .001). When we removed Neuroticism from the equation, Agreeableness emerged in part as a predictor for PTSD symptoms: for Reexperiencing, only length of service explained 30% of variance (p < .001); for Avoidance, Agreeableness brought 4% additional variance (p < .05) to the 17% explained by length of service (p < .005), and it was the only predictor for Hyperarousal, but explaining only 8% of the variance (p < .005).

We summarized these relations using a structural equation model (SEM). SEM provides a parsimonious and logical explanation of observed relationships for the measured variables. Relationships are shown in Figure 3.

- -----------------------------------------------------------------------------------------------------Please Insert Figure 3 here ------------------------------------------------------------------------------------------------------

Discussion

The aim of our study was to identify which personality traits, and particularly which personality profile, were most likely to be associated with PTSD or PTSD symptoms. The results confirmed the three expected personality profiles: Resilients, Overcontrollers, and Undercontrollers. The Resilient group comprised 31 police officers, the Overcontrollers group 43, and the Undercontrollers group 19. The Resilients had the fewest PTSD symptoms and the Undercontrollers the most (particularly for Reexperiencing). Specifically, the Undercontrollers had the highest Neuroticism scores and the lowest Extraversion and Agreeableness scores (i.e. the most vulnerable personality profile). They were also the oldest or those who had served longest in the police. Correlational analysis showed that both length of service and personality traits were associated with PTSD symptoms. Neuroticism and length of service were the two predictors of Reexperiencing and Avoidance. While Agreeableness and Extraversion had negative correlations with PTSD symptoms (i.e., both, but particularly Agreeableness, are protective traits or associated with an absence of disorders), they were no longer significant when the police officers had high scores on Neuroticism.

Our results for personality profiles are in line with those in the literature. Resilients are more resistant to job stressors and do the best job [START_REF] Garbarino | Personality traits of the five-factor model are associated with work-related stress in special force police officers[END_REF][START_REF] Jakšić | The role of personality traits in posttraumatic stress disorder (PTSD)[END_REF][START_REF] Lau | Personality types, coping, and stress in the Norwegian police service[END_REF]. Personality traits can moderate perceived stress levels. The proportion of police officers in our sample with full PTSD was relatively low compared to the findings of other authors [START_REF] Maia | Post-traumatic stress symptoms in an elite unit of Brazilian police officers: Prevalence and impact on psychosocial functioning and on physical and mental health[END_REF][START_REF] Marmar | Predictors of Posttraumatic Stress in Police and Other First Responders[END_REF], but participants were not part of an elite unit and they had not experienced a traumatic event such as 9/11 in New York. In France, in general, little consideration is given to the traumatic events that occur during police work. Officers rarely benefit from debriefing with structured psychological support. On the whole, they do not talk about any distress they may have suffered, and their supervisors also tend to ignore it. Older police officers in the lowest ranks are often those with the lowest education level and the least training. Consequently, if these police officers remain isolated, they are more at risk of developing psychic morbidity. With increasing length of service, police officers accumulate experiences of violent situations or the distress of others. They are more vulnerable to the negative effects of acute or chronic stress. Stress can be caused both by critical events and by daily stressors. Older police officers report more job pressure and fewer work injuries [START_REF] Berg | Stress in the Norwegian police service[END_REF]. The protective role of personality traits changes over time. Personality traits tend to change in a stressful environment and to be more associated with anxiety and psychological distress. This may call into question the idea that young police officers are inevitably more prone to post-trauma reactions [START_REF] Hodgins | Risk factors for posttrauma reactions in police officers: A longitudinal study[END_REF]. It also suggests that police officers should be selected on personality criteria in order to ensure their capacity to adapt to their work and to cope with the stress that it involves.

The main limitations of this study are the size of the sample, the fact that participants were still in training, and the use of self-administered questionnaires. The results should be interpreted with caution, even though the participants were from a regional training center for all categories of police officers.

This study highlights the role of personality and length of service in coping with stress and in the occurrence of PTSD symptoms in French police officers, and particularly the role of neuroticism (low emotional stability). It suggests the relevance of screening young recruits, giving precedence to those presenting with personality traits that could have a protective role (high Extraversion, high Agreeableness, high Conscientiousness or low impulsivity). It is important to recognize the stress experienced by police officers in their work and to develop strategies to help them cope with it throughout their career [START_REF] Pole | Resilience in Retired Police Officers[END_REF], such as developing social relationships and promoting peer support during and after stressful situations [START_REF] Bowling | A meta-analytic examination of the relationship between job satisfaction and subjective well-being[END_REF]. More specific support should also be given to police officers who show the characteristics of Undercontrollers because of their greater risk of developing PTSD symptoms. In sum, this research work should be replicated with a larger sample in order to gain a clearer view of the issue and perhaps to adapt actions to promote resilient functioning in a population that is often subject to post-traumatic stress.

Resilients Overcontrollers Undercontrollers

Reexperience symptoms Avoidance symptoms Hyperarousal symptoms

Figure 1 .Figure 2 .

 12 Figure 1. Resilient, overcontrolled and undercontrolled personality profiles.

Figure 3 .

 3 Figure 3. Impact of personality traits and length of service on PTSD symptoms.

Table 1 .

 1 Descriptive statistics of PTSD symptoms and personality traits.

		Mean [CI 95%]	Median Minimum Maximum Q1 Q3 SD	Cronbach's coefficient
	PCLS
	Reexperiencing score 7.9 [7.2-8.5]	7	5	19	5	10 3.1	.76
	Avoidance score	9.2 [8.5-9.8]	8	7	24	7	10 3.2	.69
	Hyperarousal score	7.0 [6.4-7.7]	5	5	23	5	8 3.2	.85
	Total score	24.1 [22.4-25.7] 21	17	54	18 27 8.1	.88
	BFI
	Extraversion	3.6 [3.4-3.7]	3.6	1.9	4.9	3.1 4.0 .7	.84
	Agreeableness	4.0 [4.0-4.1]	4.1	2.9	5.0	3.8 4.3 .4	.75
	Conscientiousness	4.1 [4.0-4.2]	4.1	2.4	5.0	3.8 4.3 .5	.80
	Neuroticism	2.2 [2.1-2.4]	2.1	1.1	4.4	1.7 2.6 .7	.83
	Openness	3.6 [3.4-3.7]	3.5	2.2	4.8	3.2 4.0 .5	.80

BFI: Big Five Inventory; PCLS: Posttraumatic Stress Disorder Checklist Scale; CI: Confidence interval; Q1: 1 st Quartile; Q3: 3 rd Quartile

Table 2 .

 2 Resilient, overcontrolled and undercontrolled personality profiles (means, standard deviations and inter-group comparisons)

		Resilients (Cl.1)	Overcontrollers (Cl. 2)	Undercontrollers (Cl. 3)	F	p	Bonferroni post-hoc test
							Cl. 3 > Cl. 1 **
	Extraversion	4.14 (.44)	3.28 (.51)	3.47 (.76)	37.05 ***	Cl. 3 > Cl. 2 (ns)
							Cl. 2 > Cl. 1 ***
							Cl. 3 > Cl. 1 ***
	Agreeableness	4.20 (.40)	4.08 (.33)	3.41 (.29)	6.53 **	Cl. 3 > Cl. 2 ***
							Cl. 2 > Cl. 1 (ns)
							Cl. 3 > Cl. 1 ***
	Conscientiousness	4.43 (.31)	3.93 (.43)	3.77 (.60)	11.31 ***	Cl. 3 > Cl. 2 (ns)
							Cl. 2 > Cl. 1 ***
							Cl. 3 > Cl. 1 ***
	Neuroticism	1.71 (.43)	2.31 (.42)	3.45 (.61)	48.92 ***	Cl. 3 > Cl. 2 ***
							Cl. 2 > Cl. 1 ***
							Cl. 3 > Cl. 1 (ns)
	Openness	3.80 (.52)	3.33 (.42)	3.88 (.67)	28.51 ***	Cl. 3 > Cl. 2 **
							Cl. 2 > Cl. 1 ***

*: p <.05; **: p <.01 and ***: p <.001

Table 3 .

 3 PTSD symptom clusters (means, standard deviations and inter-group comparisons) in the three personality prototypes

		Resilients (Cl.1)	Overcontrollers (Cl. 2)	Undercontrollers (Cl. 3)	F	p	Bonferroni post-hoc test
							Cl. 3 > Cl. 1 ***
	Reexperiencing	7.03 (2.42)	7.41 (2.79)	10.21 (3.63)	8.20 ***	Cl. 3 > Cl. 2 **
							Cl. 2 > Cl. 1 (ns)
							Cl. 3 > Cl. 1 *
	Avoidance	8.39 (2.17)	9.00 (3.39)	10.95 (3.64)	4.26	*	Cl. 3 > Cl. 2 (ns)
							Cl. 2 > Cl. 1 (ns)
							Cl. 3 > Cl. 1 *
	Hyperarousal	6.42 (2.42)	6.70 (2.49)	8.68 (4.84)	3.58	*	Cl. 3 > Cl. 2 (ns)
							Cl. 2 > Cl. 1 (ns)

*: p <.05; **: p <.01 and ***: p <.001

Acknowledgment.

We would like to thank the Regional Training Center of police officers.

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Conflicts of interest: none


Catherine Potard
email: catherine.potard@univ-angers.fr

Anaïs Madamet

Isabelle Huart
email: isabelle.huart@univ-tours.fr

Wissam El Hage
email: wissam.elhage@univ-tours.fr

Robert Courtois
email: robert.courtois@univ-tours.fr

Relationships between hardiness, exposure to traumatic events and PTSD symptoms among French police officers

Keywords: Hardiness, Posttraumatic stress symptoms, Resilience, Personality, Vulnerability

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

5

Résumé

Introduction : L'exposition à des événements traumatiques est fréquente dans le travail de la police et son impact psychologique sur les agents peut prendre la forme d'une symptomatologie sévère de TSPT. Les traits de personnalité tels que l'endurance pourraient être protecteurs en matière de santé mentale et aider à faire face aux stress et aux traumatismes.

Objectif : Cette étude visait à examiner les relations entre endurance, troubles internalisés et symptômes de TSPT dans un échantillon de policiers français.

Méthode : Les participants étaient des policiers français (N = 100, Age moyen = 32,98 ans, SD = 9,85) qui ont complété des mesures en auto-évaluation du TSPT et de la morbidité psychiatrique, de l'endurance, ainsi qu'un indice d'exposition à des incidents traumatiques dans un contexte professionnel. Police stress and burnout have been increasingly recognized as a major public health 2 issue in recent years. The level of stress induced by police work is higher than that found in 3 the general population (e.g., [START_REF] Korre | A survey of stress levels and time spent across law enforcement duties: Police chief and officer agreement[END_REF][START_REF] Webster | Perceived stress among police officers: an integrative model of stress and coping[END_REF].

4

Examples of stressful events for police officers -called critical incidents -include 5 encountering the body of someone recently dead, a colleague killed or injured accidentally, 6 responding to children who have been sexually assaulted, and road traffic accidents (Chopko,7 Palmieri, & Adams, 2015; [START_REF] Weiss | Frequency and severity approaches to indexing exposure to trauma: The Critical Incident History Questionnaire for police officers[END_REF]. A critical incident is an unexpected and 8 powerful event causing emotional reactions that overwhelm effective coping skills. Critical 9 incidents are common and stressful for police officers, but they do not necessarily involve 10 extreme violence (e.g., shooting, assault). They also include extremely depressing incidents 11 [START_REF] Carlier | Trauma at work: Post-traumatic stress disorder -An occupational health hazard[END_REF], where the police officer arrives after the event and is not actively 12 involved (e.g., traumatic injury to a child, suicide).

13

The unique nature of the stress experienced by police officers is linked to burnout and 14 negative attitudes toward people, life and work. Some police officers develop emotional or 15 behavioral symptoms, such as suicidal ideation, alcohol abuse, anxiety, or psychosomatic 16 symptoms (e.g., [START_REF] Chopko | Associations between police stress and alcohol use: Implications for practice[END_REF][START_REF] Hartley | Association between depressive symptoms and metabolic syndrome in police officers: Results from two cross-sectional studies[END_REF]Lawson, Rodwell, & 17 Noblet, 2012;[START_REF] Stanley | A systematic review of suicidal thoughts and behaviors among police officers, firefighters, EMTs, and paramedics[END_REF]. This is consistent with the findings of a 18 growing body of research that highly stressful life events may have long-term negative health consequences [START_REF] Cleland | The impact of life events on adult physical and mental health and well-being: longitudinal analysis using the GoWell health and well-being survey[END_REF][START_REF] Dohrenwend | Inventorying stressful life events as risk factors for psychopathology: Toward resolution of the problem of intracategory variability[END_REF]. Another 20 important finding [START_REF] Chopko | Critical incident history questionnaire replication: Frequency and severity of trauma exposure among officers from small and midsize police agencies[END_REF] is the strong relationship between cumulative critical 21 incidents and post-traumatic stress disorder (PTSD), including disturbance of awakening 22 cortisol activation [START_REF] Violanti | The impact of perceived intensity and frequency of police work occupational stressors on the cortisol awakening response (CAR): Findings from the BCOPS study[END_REF]. A recent meta-analysis found that 4.5% of police 23 officers may suffer from PTSD [START_REF] Berger | Rescuers at risk: A systematic review and metaregression analysis of the worldwide current prevalence and correlates of PTSD in rescue workers[END_REF] or post-traumatic stress symptoms 24 (PTSS), compared to about 1-2% of the general population (e.g., [START_REF] Lukaschek | Lifetime traumatic experiences and their impact on PTSD: A general population study[END_REF].

25

However, these figures should be treated with caution because they differ across studies.

26

Frequency [START_REF] Breslau | Previous exposure to trauma and PTSD effects of subsequent trauma: Results from the Detroit area survey of trauma[END_REF][START_REF] Vasterling | PTSD symptom increases in Iraq-deployed soldiers: Comparison 28 with nondeployed soldiers and associations with baseline symptoms, deployment experiences, and postdeployment stress[END_REF] and severity of 27 exposure [START_REF] Jakob | The impact of trauma type or number of traumatic events on ptsd diagnosis and symptom severity in treatment seeking veterans[END_REF] to critical events seem to play a 28 role in the development of PTSD symptoms and other mental health reactions. However, 29 despite routine exposure to potentially traumatic incidents, the majority of police officers do 30 not develop signs of psychological distress or PTSD. Thus, greater knowledge of protective (or resilience) factors is a major public health priority. Nevertheless, few studies have 32 investigated the factors that best protect police officers from developing these symptoms 33 [START_REF] Ellrich | Post-traumatic stress symptoms in police officers following violent assaults[END_REF][START_REF] Lee | Self-resilience as a protective factor against development of post-traumatic stress disorder symptoms in police officers[END_REF][START_REF] Yuan | Protective factors for posttraumatic stress disorder symptoms in a prospective study of police officers[END_REF].

34

Research is therefore required to identify resilience factors or general resistance 35 resources [START_REF] Antonovsky | The salutogenic perspective: Toward a new view of health and illness[END_REF][START_REF] Tusaie | Resilience: A historical review of the construct[END_REF]. Resilience is defined as the capacity for 36 successful adaptation despite significant adversity. Hardiness appears to be one of the factors 37 that may contribute to this adaptation [START_REF] Bartone | Psychological hardiness predicts adaptability in military leaders: A prospective study[END_REF]Escolas, Pitts, 38 Safer, & Bartone, 2013;[START_REF] Maddi | On Hardiness and Other Pathways to Resilience[END_REF][START_REF] Pitts | Effects of hardiness and years of military service on posttraumatic stress symptoms in U.S. Army medics[END_REF], and it 39 has been identified as a resistance resource [START_REF] Kobasa | Stressful life events, personality, and health: An inquiry into hardiness[END_REF][START_REF] Kobasa | The hardy personality: Toward a social psychology of stress and health[END_REF][START_REF] Maddi | Hardiness as a pathway to resilience under stress[END_REF]. Hardiness is 40 considered as a healthy personality disposition and shows negative correlations with 41 neuroticism, and positive correlations with four other Big Five personality traits (Conscientiousness, Extraversion, Openness, and Agreeableness; e.g., Bartone, Eid, and hence remains relatively stable over time, even if it is susceptible to change under certain 45 circumstances [START_REF] Maddi | The story of hardiness: Twenty years of theorizing, research, and practice[END_REF]. health of police officers. However, other studies have produced divergent results (Marchand,75 Nadeau, [START_REF] Marchand | Predictors of posttraumatic stress disorder among police officers: A prospective study[END_REF]. A possible explanation is that most 76 empirical studies do not take into consideration the symptoms of PTSD (avoidance, intrusion 77 and hyperarousal). Another possibility is that many studies fail to consider the frequency and 78 severity of critical incidents. Therefore, the links between hardiness, critical incident history,

79

PTSD and its symptoms (avoidance, intrusion, hyperarousal, and general mental health) need 80 to be clarified.

81

The purpose of the present study was to examine how hardiness can act as a buffer 82 against the cumulative stress of police officers. To this end, we conducted a series of analyses 83 to evaluate the relationships between hardiness, stressful life events (critical incidents), and 84 PTSD symptomatology (avoidance, intrusion, and hyperarousal) among police officers.

Methods

were older than women. A majority (58%, n = 58) of the participants were patrolmen 90 (gardiens de la paix) or judicial police officers (officiers de police judiciaire), 41% (n = 41) 91 were auxiliary police officers (adjoints de sécurité), and 1 participant (1%) was a forensic 92 technician (technicien de la police scientifique). All were from the Centre-Val de Loire region 93 of France. Average length of service was 10.96 years (SD = 9.85). In our sample, women had 94 worked as police officers for fewer years than men (t (99) = -2.00, p = .03). ------------------------------------------------------------------------------------------------------Please Insert Table 1 here ----------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------Please Insert Table 2 here ------------------------------------------------------------------------------------------------------161

Multiple regression analysis

162

A multiple regression analysis was conducted to determine which variables were 163 significant predictors of each of the outcome variables in order to explore whether Hardiness 164 has an impact on the formation of PTSD symptoms, and if so, which of its components has 165 the greatest influence. For this analysis, Hardiness scores were the independent variables, 166 psychiatric morbidity served as mediator, and PTSD symptoms as the dependent variable.

167

Significant predictors of PTSD symptoms in our sample are presented in Table 3. The result 168 of this analysis shows that Control and Commitment predicted lower PTSD symptoms. The Table 4).

- -----------------------------------------------------------------------------------------------------Please Insert Table 3 here ----------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------Please Insert Table 4 here ------------------------------------------------------------------------------------------------------182

In sum, as predicted, the control variables did not eliminate all the significant correlations 183 between hardiness and the GHQ and PCL-S. This study examined the protective factor of hardiness, which is known to be closely 186 related to psychological resilience, particularly in certain high-risk occupations. Police 187 officers experience many potentially life-threatening events, which require adjustment or 188 coping [START_REF] Chopko | Critical incident history questionnaire replication: Frequency and severity of trauma exposure among officers from small and midsize police agencies[END_REF]. It is therefore crucial to identify factors that enable them to cope 189 with stressful experiences. Hardiness is a dispositional factor associated with coping with 190 adversities [START_REF] Maddi | Hardiness as a pathway to resilience under stress[END_REF]. Two previous studies highlighted hardiness as a potential 191 moderator or buffer against stress symptoms among police officers [START_REF] Andrew | Hardiness and psychological distress in a cohort of police officers[END_REF]192 Tang [START_REF] Hammontree | These findings support the view that hardiness contributes to the mental References[END_REF]. However, the results produced substantially different results. In One hypothesis was that hardiness could have a particular relationship with specific cluster(s).

197

In the present study, we controlled for the role of critical incidents, age and length of service 198 in this potential relationship between stress symptoms and hardiness.

199

The results showed that the hardiness components of Commitment and Control have 200 significant negative correlations with PTSD symptoms and psychiatric morbidity. This is 201 consistent with previous findings that hardiness has a close relationship with psychological 202 well-being and the ability to cope with anxiety [START_REF] Bartone | Psychological hardiness predicts adaptability in military leaders: A prospective study[END_REF][START_REF] Escolas | The protective value of hardiness on military posttraumatic stress symptoms[END_REF]203 Maddi, 2005;[START_REF] Pitts | Effects of hardiness and years of military service on posttraumatic stress symptoms in U.S. Army medics[END_REF], although our results showed no significant association with [START_REF] Andrew | Hardiness and psychological distress in a cohort of police officers[END_REF] results that showed similar findings only among women 210 police officers. A high level of control has been related to an internal locus of control (e.g., 211 [START_REF] Kooranian | The relationship between hardiness/ locus of control and burnout in nurses[END_REF]; in other words, police officers with this disposition 212 could consider critical events to be under their own control and thus feel less stress. This 213 appraisal of their ability to cope with the situation could prevent PTSD (secondary appraisal, 214 [START_REF] Folkman | Stress: Appraisal and coping[END_REF]. Control over life events (dispositional control) is an important predictor of 215 well-being, but it is possible that relationships between Control and PTSD symptoms are also 216 influenced by situational control over police work-related stressful events (i.e., response to 217 meet the demands of specific life stressors).

218

In the present study, the Commitment and Control facets of hardiness predicted lower

  Résultats : L'analyse des corrélations a montré une relation spécifique entre l'endurance et les symptômes de répétition (intrusion) et d'évitement du TSPT, mais pas avec l'hyperactivité neurovégétative. L'étude des corrélations entre endurance et mesures de morbidité psychiatrique montre des corrélations négatives élevées pour le contrôle et l'engagement, mais aucune corrélation significative pour la dimension challenge. Les résultats de l'analyse de régression indiquent que seuls les symptômes de répétition et d'évitement ont été significativement médiés par le contrôle et, dans une moindre mesure, par l'engagement. Conclusion : Les résultats révèlent que l'endurance a un effet protecteur sur les symptômes de TSPT chez les policiers. Mots-clés : Endurance ; Trouble de stress post-traumatique ; Résilience ; Personnalité ;

95

  Participants were recruited in a national police training centre. Participants responded 96 anonymously, and all the data were collected via self-administered paper questionnaires. All 97 the participants gave their informed consent after the purpose of the study and the procedure 98 had been explained, emphasizing the confidentiality and anonymity of the data. Clear and 99 precise instructions were given, and the importance of giving honest answers was stressed. No 100 incentive was provided. Participants with one value or more missing on the measures were 101 Because previous studies have reported sociodemographic 105 differences in PTSD (e.g. Kun, Tong, Liu, Pei, & Luo, 2013), participants were asked to 106 provide details of their gender, marital status, age, and years of police service. Critical incidents. The Critical Incident History Questionnaire (CIHQ; Chopko et al., 108 2015; Weiss et al., 2010) is a 39-item self-report questionnaire that provides a quantitative 109 estimate of cumulative exposure to critical incidents. Participants estimated the frequency 110 (the number of times they have experienced the incident) and severity (how difficult each 111 incident was to cope with) of 34 work-related critical incidents (e.g., encountering the 112 body of someone recently dead, being shot at, colleague killed intentionally; see Table 1

113

  for percentages of police officers reporting each item, and their frequency of exposure to the 114 incident). The total score was the sum of frequency of exposure and a rating score of coping 115 difficulty for each item. The CIHQ demonstrates good internal consistency. 116 PTSD. The PTSD Checklist-Specific Version (PCL-S; Ventureyra, Yao, Cottraux, 117 Note, & De Mey-Guillard, 2002) is a brief and practical self-report assessment of the severity 118 of PTSD-related symptoms (DSM-IV criteria) in the past month. Participants rated the level 119 of distress experienced for 17 items on a 5-point scale (from 1 -not at all to 5 -extremely), 120 summed to produce a total score (Cronbach's alpha .95). Items can be divided into 3 sub-121 scales: Reexperiencing (items 1-5), Avoidance (items 6-12) and Hyperarousal (items 13-17).

122

  Scores range from 17 to 85, with higher scores indicating greater PTSS severity. The PCL-S 123 (specific) asks about symptoms in relation to an identified stressful experience, a specified 124 event. 125 Mental health. The 28-item General Health Questionnaire (GHQ-28; Goldberg & 126 Williams, 1988) is a well-validated questionnaire of mental health, measuring emotional 127 distress and psychiatric morbidity. It is scored on a 4-point Likert scale, with higher scores 128 indicating a higher level of emotional distress. The GHQ-28 has 4 sub-scales: Somatic 129 symptoms, Anxiety-insomnia, Social dysfunction and Severe depression.

  13self-report instrument measuring the three facets of hardiness: Commitment (a feeling of 132 dedication to tasks and meaning-making, e.g., "Most of my life gets spent doing things that 133 are meaningful"), Control (a sense of autonomy or influence over one's life, e.g., "How things 134 go in my life depends on my own actions"), and Challenge (a perception that obstacles are 135 opportunities for growth, e.g., "I enjoy the challenge when I have to do more than one thing at 136 a time"). Participants rate the 15 items on a 4-point Likert scale (0 -not at all true to 3 -137 completely true) and scores are summed to give an overall hardiness score.

  analyzed using Statistica version 13 software. Means and standard 140 deviations were calculated to determine the level of psychological well-being and personality 141 traits. A two-sample t-test was conducted to compare men and women with respect to the 142 main variables of interest. We performed a series of regression analyses in which PTSD 143 features were the dependent variables, with hardiness scores as regressors. Finally, partial 144 correlation coefficients and a multiple regression analysis were conducted to determine the 145 relationship between PTSD symptoms and each outcome variable, controlling for the critical 146 incident score, age and length of service. Differences were considered significant when p the total hardiness score and the subcomponents of hardiness 151 were positive (r >.66, p <.001). Additionally, the sub-dimensions of Commitment and 152 Control, and Commitment and Challenge, were positively correlated (respectively, r = .46, 153 p<.001, and r = .27, p<. 01). Table 2 shows the relationships between hardiness scores, PTSD 154 (PCL-S scores) and psychiatric symptoms (GHQ scores) using Spearman Correlation 155 analysis. Hardiness had a significant negative correlation with psychological symptoms 156 (PTSD and GHQ) (-.26 to .52, p<.01). However, differences were observed in the hardiness 157 sub-facets; Commitment and Control had significant negative correlations with all variables 158 (respectively, r -.27 to -.42 and r -.24 to -.50), but Challenge showed no significant 159 correlations. There was a high correlation between Hardiness and Somatic symptoms (r = -160 .52, p< .001).

  correlations were calculated to control for the correlations among the 174 independent variables in the regression model. Partial correlations were analyzed to 175 investigate the relationship between hardiness and mental health after controlling for age, length of service and critical incident. Table4displays the partial correlation results. In sum, 177 the results show no significant correlations between challenge and GHQ scores or PTSD 178 scores. Commitment showed significant negative correlations with PTSD and psychiatric 179 symptoms, but partial correlation analysis yielded lower correlations (r -.24 to -.38, p< .05).180The analysis revealed significant negative correlations between Control and psychological 181 symptoms (r -.24 to -.48, p< .05).

  193 response to this discrepancy, this study examined the relationships between the components 194 of hardiness and the three specific symptom clusters of PTSD: Reexperiencing -cognitive 195 dimension, Avoidance -behavioral dimension, and Hyperarousal -physiological dimension.

  196

204

  Challenge. Each of the three PTSD clusters had a significant negative correlation with both 205 the Control and Commitment components of hardiness. High levels of Control and 206 Commitment were associated with fewer reported PTSD and/or psychiatric symptoms, 207 including somatic problems. These results are consistent with previous studies reporting a relationship between Control and Commitment and physical health (e.g. Shepperd & Kashani, 209 1991) and extend

  219cognitive (Reexperiencing) and behavioral (Avoidance) symptoms of PTSD, but not 220 physiological symptoms(Hyperarousal). The latter could be attributed more to biological than 221 dispositional variables (e.g., stress hormones). In each case, Control had the main influence, 222 accounting for 16% of the explained variance for Reexperiencing and 12% of the explained 223 variance for Avoidance (and 7% for Hyperarousal). The consistent finding in this work is that 224 Control and Commitment are negatively related to post-traumatic stress symptoms and mental 225 health disorders. Our results highlight the importance of examining the different components 226 of hardiness rather than hardiness as a whole. In particular, we observed that Control 227 moderated the experience of cognitive and behavioral stress symptoms, but less than 228 physiological reactivity. Police officers with a high level of control may feel they have control 229 over their lives and their ability to navigate in their world, and are therefore less likely to 230 develop PTSD symptoms. To a lesser extent, Commitment could play a protective role, because it gives one a sense of purpose and encourages the development of social 232 relationships that can be supportive during (and after) stressful situations (Eschleman, The results of our study reveal the importance of the personality trait of hardiness in 276 preserving psychological well-being in stressful occupations. Consistent with previous studies 277 of military subjects, we found significant negative correlations between hardiness and mental 278 disorder scores, either anxiety disorder symptoms or other internalization symptoms among 279 police officers. Psychological hardiness as a direct or "buffering effect" on life stress could be 280 an internal resistance resource protecting against the adverse effects of stress and associated 281 mental disorders. Furthermore, the present study provides additional evidence that hardiness, 282 particularly its Control facet, could protect police officers from PTSD symptoms. Hardiness, 283 and particularly the subdimension of control, was significantly and negatively associated with 284 the symptoms of reexperiencing and avoidance/numbing. The trait of psychological hardiness 285 thus seems to act as a protective factor in relation to PTSD symptoms and might also act as a 286 buffer against other negative mental health effects of stress. This finding could prompt 287 researchers to investigate the differential impact of the separate facets of hardiness on the 288 three PTSD clusters (reexperiencing, avoidance, hyperarousal) as well as the new 289 dissociative-PTSD subtype (DSM-5). In particular, peri-traumatic dissociation and 290 derealization symptoms in PTSD should receive specific attention in future studies (Dorahy & 291 van der Hart, 2015; Nijenhuis, 2017). The apparent benefit of hardiness could be of practical 292 interest to clinicians and occupational psychologists as a selection criterion for training police 293 officers. If further studies confirm the importance of the hardiness personality construct in the 294 long-term adaptation to stressful events in police work (as for former prisoners of wars; 295 Zerach, Karstoft, & Solomon, 2017), early identification and screening of 'dispositional 296 resilience' (Bartone, 2007) among police officers, with particular support for individuals who 297 are at risk, and integration of hardiness training (including commitment and control) in police education, should be regarded as channels for a PTSD prevention strategy. The hardiness 299 training programs for stress resilience in military contexts described by Bartone, Eid and 300 Hystad (2016) could provide a useful basis for developing such a strategy.

Table 1

 1 Critical Incident History Questionnaire: frequency and mean severity of events.

	Mean (SD)

Table 2

 2 Pearson's correlations between hardiness and psychological well-being.

	PTSD symptoms

* p< .05; ** p < .01; *** p < .001; ns: non-significant.

Table 3

 3 Hierarchical multiple regression results for the prediction of PTSD symptoms. = .21; F (2,90) = 12.38, p<.001 R 2 = .17; F (2,90) = 6.11, p<.001 R 2 = .10; F (2,90) = 5.06, p<.01

			Reexperiencing			Avoidance			Hyperarousal
	Predictor variables	Effect size	𝛽	t	p-value Effect size	𝛽	t	p-value Effect size	𝛽	t	p-value
	Control	.16	-.29	-2.80	***	.12	-.25	-2.36	***	.07	-.20	-1.82	*
	Commitment	.05	-.26	-2.47	*	.05	-.24	-2.19	*	.03	-.20	-1.72	*
	Total effect	R 2

*: p < .05; **p < .01; *** p < .001.

Table 4

 4 Partial correlation analyses for hardiness and psychological well-being, covarying for age, length of service and critical incident exposure.

	Variables		1	2	3	4	5	6	7	8	9	10
		1.Challenge	--	.15 ns	-.01 ns	-.08 ns	-.03 ns	-.03 ns	-.04 ns	.07 ns	.14 ns	.05 ns
	Hardiness	2.Commitment		--	.36 ***	-.27 ***	-.32 **	-.38 ***	-.31 **	-.31 **	-.25 *	-.24 *
		3.Control			--	-.43 ***	-.48 ***	-.24 *	-.33 **	-.31 **	-.28 **	-.23 *
		4.Somatic symptoms				--	.76 ***	.31 **	.55 ***	.37 ***	.31 *	.44 *
	Psychiatric morbidity	5.Anxiety-insomnia					--	.44 ***	.59 ***	.36 ***	.32 ***	.43 ***
		6.Social dysfunction						--	.40 ***	.29 **	.24 *	.32 ***
		7.Severe depression							--	.35 ***	.32 **	.44 ***
		8.Reexperiencing								--	.61 ***	.50 ***
	PTSD	9.Avoidance									--	.57 ***
		10.Hyperarousal										--
	* p< .05; ** p < .01; *** p < .001; ns: non-significant.

[START_REF] Bartone | Big five personality factors, hardiness, and social judgment as predictors of leader performance[END_REF][START_REF] Zhang | Hardiness and the Big Five personality traits among Chinese university students[END_REF]. Hardiness is considered as a personality trait

Bowling, & Alarcon, 2010).

Acknowledgment. We would like to thank the Regional Training Center of police officers.

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Participants and procedure

direct effect of Commitment on PTSD symptoms was of much smaller magnitude than Control. Moreover, the overall effects of hardiness on PTSD symptoms were significant (see