Burnout refers to a cluster of symptoms resulting from chronic emotional and interpersonal stressors in one’s workplace [18]. Burnout is described as a work-related state which originates from a state of mental and emotional fatigue related to the employee’s coping strategies. Burnout symptoms usually include fatigue, anxiety, and irritability. Although some of these symptoms are similar to those of psychological distress and depression, this work-related state is unique in that it pertains to the workplace and its workers. Burnout is composed of three main dimensions: emotional exhaustion, cynicism, and lack of professional efficacy [18]. Emotional exhaustion is the cornerstone of burnout and the most visible manifestation of the work-related state [18]. As such, emotional exhaustion is the first dimension of burnout. This negative mental state refers to a feeling of being overstrained and fatigued and usually results from an extended involvement in an over-demanding work situation [19]. Cynicism is the second dimension of burnout and is usually characterized by a negative attitude toward work or an excessively detached response to other people at work (also termed depersonalization). Cynicism usually includes indifference, disengagement, lack of enthusiasm, or aloofness toward work in general [19,20]. Lastly, lack of professional efficacy (also termed reduced personal accomplishment) is the third dimension of burnout and refers to a reduced perception of self-efficacy and productivity at work. It is worth mentioning here that the three dimensions of burnout are distinct and mutually exclusive. Professional efficacy (positively worded) is considered distinct from the other two dimensions [20].

Psychological demands generally refer to work variables putting strain on a worker’s mental capacities. These variables could include contradictory demands, workload assigned, and timeframe. Job demands can deplete workers’ mental and physical resources, increasing one’s risk of suffering from health problems [7]. Numerous empirical studies have demonstrated the direct association between high job demands and burnout [9,10,11,12]. For instance, Ståhl et al. [21] demonstrated that burnout and psychological demands at baseline were associated with burnout at follow-up. A recent study also demonstrated that significant increases in one’s workload negatively affects one’s sense of self-efficacy [22]. According to Mühlenmeier et al. [23], the level of time pressure as well as the temporal pattern of change across one’s work week are both important in terms of mental well-being. Despite numerous studies demonstrating the link between psychological demands at work and burnout, a gap remains. This gap is two-fold. The first aspect pertains to the association between changes in psychological demands over time (e.g., increasing or decreasing psychological demands) and burnout. The second aspect pertains to a lack of longitudinal studies evaluating the moderating role of resources in the demands–strain relationship. According to Downes et al. [17], changes in job demands may be a particularly important factor to consider, with jobs changing more rapidly than ever in today’s work environment. That could be experienced as a source of uncertainty and stress, especially for employees with low levels of personal and social resources. As such, changes in psychological demands (especially when psychological demands increase over time) could exert pressure on employees’ resources.

Stress at work can affect employees differently. An employee’s response to a stressful situation, such as high job demands, depends in part on that person’s perception of the situation [24]. Depending on an employee’s interpretation, job demands could be perceived as more or less controllable [24]. To face these job demands, employees usually rely on their personal resources [25]. Among these personal resources are specific personality traits such as high self-esteem and an internal locus of control, which can moderate the impact of changing psychological demands over time on burnout. Self-esteem refers to an individual’s personal assessment of themselves that usually translates into an attitude of self-approval or disapproval [28]. As for locus of control, this personality trait refers to the degree to which individuals perceive that they have control over important events in their lives [29]. Johnson et al. [30] found that self-esteem plays a direct as well as an indirect role (via stress) in burnout. Similarly, internal locus of control seems to play a key role in how nurses cope with stress and burnout [31] and a moderating role between job demands and job satisfaction [32].

A second resource to consider is social support. Working entails a certain level of interaction with other people. The quality of these interactions could play a role in employees’ well-being [33]. More specifically, employees facing changes in job demands could rely on social support from their supervisor and coworkers to moderate the effects of such demands. Previous studies have highlighted the importance of social support in employees’ mental health. In a sample of nurses, job resources, including social support, seemed to play a moderating role between job demands and burnout [34]. Social support also seems to play a moderating role between job demands and an individual’s appraisal of these demands [35], as well as work absenteeism [36]. In a sample of teachers, social support from supervisors was associated with a lower risk of burnout [37]. The same findings also extended to a sample of nurses, with social support from supervisors and coworkers playing an important role in burnout prevention [38]. Those same studies pointed to the negative impact that a lack of social interaction (between employees and their supervisors, as well as among themselves) could have on mental health [7]. Based on these previously presented findings, individual and social resources could play a role in the relationship between a stressor (e.g., increase in job demands) and its repercussions on an employee’s mental health (e.g., burnout). More specifically, personal and social resources could determine how employees respond to changes in job demands over time and the resulting association with burnout.