Une étude sur les déterminants biologiques, psychologiques et du travail de l'épuisement professionnel

This study aims at identifying factors associated with salivary cortisol secretion and burnout. Several objectives are listed below. First, it aims to better understand the contribution of the work conditions (skill utilization, decision authority, psychological demands, physical demands, irregular schedule, number of working hours, social support from colleagues and supervisors, job insecurity) on salivary cortisol secretion as well as the moderating role of personality traits (extraversion, agreeableness, neuroticism, consciousness, openness, self-esteem, control center) on the relationship between work conditions and salivary cortisol. This thesis also aims to establish the contribution of work conditions on burnout and the moderating role of personality traits on the relationship between the work conditions and burnout. Finally, this thesis aims to verify whether salivary cortisol plays a mediating role in the relationship between work conditions and burnout as well as identify the effects of moderated mediations of the personality traits on the relationship between work conditions and salivary cortisol.  The objectives of this study address some of the limitations identified in previous research, mainly the integration of biological, psychological determinants and work conditions in understanding burnout. We also propose a conceptual model that tries to identify how these different stressors can cause a salivary cortisol secretion dysregulation and evaluate if this dysregulation is associated with burnout. Finally, this conceptual model seeks to explain how personality traits can influence how these variables are interconnected, that is whether personality plays a moderating role. This model stems from four specific theories, including Selye’s (1936) biological perspective. Selyes’s work is interested in the physiological response of an organism subjected to a stressor. When faced with a threat, the body is in constant effort to maintain its balance (homeostasis) and tolerates very few changes to this balance. If excessive changes are induced, a stress response is activated to ensure maintenance of body base balance. Secondly, the conceptual model is based on Lazarus and Folkman model (1984), which postulates that the stress response depends mainly on the evaluation that individuals make of the stressful situation. Thirdly, it is also based on Pearlin model (1999), which postulates that individuals exposed to the same stressors are not necessarily affected in the same way. Finally, the conceptual model of this thesis is based on Marchand model (2004), which postulates that the individuals reactions depend on the decoding actors do regarding the constraints and the resources that affect them.  Various hypotheses therefore emerge from this theoretical conceptualisation. The first is that work conditions interact directly with salivary cortisol. The second is that the work conditions directly contribute to burnout. The third is that salivary cortisol mediates the relationship between work conditions and burnout. The fourth is that the relationship between work conditions and salivary cortisol is moderated by personality traits. The fifth is that the relationship between work conditions, salivary cortisol and burnout is moderated by personality traits. Multilevel regression models and causal path analyses were conducted on a sample of Canadian workers from SALVEO study. The results are presented as three articles submitted for publication, which are chapters 4-6 of this thesis. Overall, the integrative biopsychosocial model proposed as part of this doctoral thesis sheds light on the complexity of burnout which is a biological, organizational and individual explanations. This finding allows us to offer a broader and multi-understanding as well as contributing to the research on an issue of concern for organizations, society and workers. Indeed, the inclusion of personality traits and secretion of salivary cortisol in the study of burnout ensures an integrated and more objective analysis. This thesis concludes on the implications of these findings for research, and the benefits it brings to the workplace.

Keyphrases: Big Five, salivary cortisol, burnout, personality traits, Big Five, self esteem, locus of control, work conditions