Introduction
Work-related stress and associated sickness absence is highly prevalent [
1,
2]. Various models describe risk factors for work-related stress and its developmental mechanisms. The Job-Demand Control Support (JDCS) model of Karasek et al. [
3‐
5], for example, states that high job-demands in combination with low job-control and/or low support elevate the risk on health problems and impaired daily functioning. Alternatively, the Transactional Model of Lazarus and Folkman [
6] posits that when external demands exceed a person’s perceived ability to cope with these demands for a lasting period, health problems and impaired functioning develop. Both models state that durable exposure to high work-load can result in a state of work-related stress, which affects daily functioning and results in sickness absence. Both models are supported by substantial empirical evidence (see for example Nieuwenhuijsen et al. [
7], Yu et al. [
8], Lim et al. [
9], and Häuser et al. [
10] for reviews). Hence, substantial progress has been made in understanding the process of developing work-related stress. No less important, though far less studied, is the process of recovery from work-related stress [
11,
12]. In an attempt to further enhance the insight in this recovery process, we focused on two indicators of recovery, that is, complaint reduction and work-resumption. We searched for predictors of these indicators of recovery and assessed to what extent they are related.
While complaint reduction and work-resumption are both measures of recovery, they may be affected differentially by other factors. For example, the motivation to resume work may be expected to increase with a rising risk of losing one’s job, but the risk of losing one’s job generally poses a threat, rather then promotes one’s health. As little is known about determinants of symptom reduction and work-resumption, variables regarding personal (e.g. coping), work-related (e.g. job demands), and illness-related (e.g. chronicity of the complaints) characteristics may be considered, since they have shown to be relevant in the context of work-related stress and health problems (see for example Nieuwenhuijsen et al. [
7], Yu et al. [
8], Lim et al. [
9], and Häuser et al. [
10] for reviews).
In the process of recovery from work-related stress, it may seem apparent that a reduction of complaints, or conversely, gains in health, precedes work-resumption. Accordingly, one would expect complaint reduction to predict work-resumption. Various findings suggest, however, that once absent from work, subsequent work-resumption and complaint reduction are relatively independent processes. For example, it has been shown that work-resumption frequently takes place before symptoms have reduced to normal levels [
13‐
15], while others demonstrate that symptom reduction does not automatically result in work-resumption [
16]. Also in chronic fatigue, a condition characterized by similar complaints and etiology as work-related stress, recovery and work-resumption are predicted by different variables [
12]. Finally, work-resumption was successfully promoted by short cognitive behavioral interventions conducted by caregivers in the work environment (e.g., occupational physician [
13,
15,
17]), while complaint reduction was not achieved by these interventions [
13,
15,
17]. Thus, it remains to be tested whether complaints reduction precedes work-resumption.
In sum, this study aimed to assess the process of recovery from work-related stress by studying two aspects of recovery, that is, complaints reduction and work-resumption. This was done by identifying predictors of complaints reduction and work-resumption and testing whether complaints reduction preceded work-resumption. In order to further assess the mechanism of recovery, we assessed complaints improvement as a mediator in the association between predictors and work-resumption. Identification of predictors of recovery and/or evidence for mediation processes could provide relevant information for screening and/or treatment purposes.
For the predictors of complaints reduction and work-resumption, selection of the variables age, gender, and education was based on prediction studies targeting complaint reduction and/or work-resumption among patients absent from work because of fatigue and/or work-related stress [
18‐
20]. Furthermore, predictors associated with the development of stress-related complaints were included. These predictors were: (a) work-characteristics as specified in the JDCS-model [
4]; (b) inadequate coping, which has been associated with stress in the Transactional Model of Lazarus and Folkman [
6]; and (c) dysfunctional cognitions, which are considered a risk factor for mood disorders [
21]. It was assumed that more extreme values on these predictors would be associated with more severe complaints and/or less optimal conditions for recovery (e.g., low support may enhance distress). Finally, the predictors duration of complaints and duration of sickness absence were included. Duration of illness was used as an indicator of severity of complaints and/or an indirect indicator of adverse conditions for recovery (e.g., presence of an ongoing stressor such as a conflict with the employer); hence, a longer duration of either illness and/or absence duration was expected to negatively predict recovery.
Concerning the relation between complaint reduction and work-resumption, we expected at least some predictive power of complaint reduction, as a certain level of adequate daily functioning is required to be able do ones work. With respect to the mediation model, given the numerous potentially relevant predictors included, we expected to identify at least one factor that would stimulate work-resumption through complaints reduction.
This study was conducted among individuals absent from work because of work-related stress. It was part of a comprehensive project in which the effectiveness of individual and group stress-management training (SMT) was investigated. SMT did not have additional effects to care as usual on complaints or sickness absence, except for indications of superior effectiveness of individual SMT in the subgroup with lower depressive complaints [
14].
Discussion
This study aimed to elucidate the process of recovery of work-related stress by (a) identifying predictors of reduction of work-related stress complaints and work-resumption, and (b) exploring the association between these two aspects of recovery through a mediation model among patients with work-related stress. Distress and burnout complaints reduced considerably over the 13-months period, reaching borderline clinical levels (for a definition of clinical levels, see for example [
27,
28,
38]). After 13 months, work was completely resumed by 68 % of the sample. Predictors of stronger recovery of distress complaints were being a male, working less hours per week, having less decision authority, having more co-worker support, and being absent from work for a shorter period. Predictors of recovery of burnout complaints were being a male, being higher educated, being younger, having a weaker tendency for avoidant coping, having less decision authority, having more job security, and having more co-worker support. Regarding baseline predictors, work-resumption was predicted solely by age. In addition, work-resumption was predicted by a reduction of burnout complaints in the past 3 months. No evidence for substantial mediation of the association between age and work-resumption by a reduction of burnout complaints was found. Thus, while predictors of complaints reduction and work-resumption were different, the fact that reduction of burnout complaints preceded work-resumption supports at least some relatedness between complaints reduction and work-resumption.
Our results concerning predictors of work-related complaints and work-resumption were in line with studies in related fields. For example, the variables gender, age, and co-worker support were associated with stress-related complaints in the same direction as found in the current study [
11,
12,
38‐
41]. The finding regarding decision authority was not in concordance with the JDCS model [
3‐
5]. These inconsistent findings may support the presumed curvilinear relationship between decision authority and health assumed by Warr [
42]. Furthermore, less avoidant coping has been associated with less stress complaints [
39] and recovery of depression [
43]. Unexpectedly, none of the dysfunctional attitudes predicted reduced complaint reduction, though mean values of the attitudes at baseline were elevated [
44,
45] and irrational cognitions have shown associations with distress complaints [
46]. Inclusion of treatment condition in the models was not the reason for not findings effects; analyses without treatment condition in the model resulted in similar, non-significant coefficients (results not shown). Regarding sickness absence, higher age appears to be a consistent predictor of long-term absenteeism in patients with mental health problems, adjustment disorder, or chronic fatigue [
11,
19,
47].
With respect to the mediation analysis, the association between age and work-resumption was almost entirely independent of reduction of burnout complaint. Hence, more gradual work-resumption among older participants cannot be ascribed to slower complaint reduction. An explanation for this finding may be that older patients have different attitudes towards work, which may reduce their motivation to return to work. Alternatively, employers may have different attitudes towards reintegrating older employees as compared to younger ones.
Of note, this study showed that it is relevant to distinguish between distress and burnout complaints as reductions of these complaints were predicted by different variables. In addition to the common predictors sex, decision authority, and co-worker support, reduction of distress complaints was uniquely predicted by working hours and absence duration. Unique predictors of reduction of burnout complaints were education, avoidant coping, and job-security. Moreover, only change of burnout complaints was associated with work-resumption. Post-hoc analyses (results not shown) revealed that distress complaints were also associated to work-resumption but in a different manner. Instead of change of distress complaints, it appeared that a lower level of distress complaints measured 3 months earlier predicted work-resumption. This finding suggests that a more trait-like level of less distress predicts more recovery.
As little is known about predictors of recovery of complaints in samples with a clinical level of work-related stress, we can only speculate about explanations for the observed associations. Females, for example, frequently have more additional obligations, such as care of the household and children (e.g., [
48]), which may slow down recovery as compared to males. Individuals with less education generally tend to have more additional stressors, like for example financial problems (e.g., [
49]), and tend to be less healthy (e.g., [
50]), which may impair their recovery. Older individuals may recover at a slower pace because of their physical limitations. Older workers indeed need more time to recover than younger workers (e.g., [
51]). Regarding working hours, findings suggest that working more hours is associated with poor health, which may impair subsequent recovery. To illustrate, working hours is associated with more psychosomatic complaints (e.g., [
52]), with an unhealthier life style and with more adverse physiological changes (e.g., [
53,
54]). Among individuals with more decision authority, who generally have jobs with higher responsibilities, continuous worrying on their responsibilities during their absence may hinder recovery. Individuals with less job security are likely to remain distressed while absent from work due to their uncertain future, which may prevent recovery. In support of this suggestion is that job insecurity is associated with more health complaints (e.g., [
55,
56]). Reporting less co-worker support may indicate conflicts with colleagues. Conflicts with co-workers may continue to affect health during absence. It has been demonstrated that conflict with co-workers is indeed associated with more health complaints (e.g., [
57]) and with delayed onset of recovery of fatigue complaints [
58]. A stronger tendency of avoidant coping may prevent recovery since problems at work or during absence are less likely to be adequately solved, which may result in continuation of negative affect [
59]. In addition, a stronger avoidant coping style may result in unhealthier life style behaviors [
59,
60] that may in their turn delay recovery. Finally, being absent for a longer time may result in less recovery due to diminished hope on a positive outcome, reduced self-confidence, reduced positive attitudes towards work, or an increased sense of detachment to the workplace.
Considering the above proposed mechanisms, various predictor variables, though clearly in need of cross-validation, are candidates for treatment purposes. Person-related variables, e.g., coping, are already involved in cognitive-behavioral treatment (CBT). Job-related variables are less easily influenced in psychological treatments aimed at the individual such as CBT. However, regarding co-worker support, employers may encourage co-workers to support an absent patient. Employers may also enhance alternative job resources such as feedback and supervisory support to facilitate a more effective coping with job demands. For example, other researchers have observed a positive association between supervisor communication and shorter absence duration [
61], supporting a more active role of the supervisor in the process of work-resumption. Furthermore, influence on job-characteristics such as working hours and decision authority may be increased by more involvement of the occupational physician in the treatment-process. Occupational physicians may add to the insight in a potential misfit between the patient and his/her work, and could stimulate the employer to make certain adjustments to the working conditions. The association between the illness-related variable absence duration and general complaint recovery may also be informative for intervention purposes. Longer absence duration may lead to aggravation of certain complaints, e.g. anxiety, or loss of day structure. Patients with longer absence duration did not have more severe complaints at baseline; associations between absence duration and complaints were low (<.20) and non-significant. This finding suggests that (partial) work-resumption may be beneficial, even though complaints may not have abated completely. However, further research is required to further investigate the association between absence duration and general complaints reduction, and investigate potential beneficial effects of earlier work-resumption.
Finally, the predictors that cannot, or with great difficulty, be changed through interventions, such as gender, age, education, and job security, can be considered as indicators of groups at risk, for whom specific interventions may be designed. Other researchers, for example, have proposed a practically applicable prediction rule based on the predictors such as age and education level that occupational physicians could use in order to identify cases at risk for unfavorable outcomes [
18]. However, again, since research on predictors of recovery is scarce, replication of the results is prerequisite, before actual guidelines for identifying groups at risk can be provided.
A strength of the current study is the longitudinal design including repeated measures of both complaints and work-resumption. A main limitation of this study is that participants were predominantly employees working in small and medium size companies, and willing to participate in this intervention study, limiting generalisation to other groups of employees or the self-employed.
Future research may first of all focus on replication of the current findings. Further, future studies may aim to map the processes of recovery and work-resumption in more detail, by adopting a design in which predictors and potential mediator variables are measured repeatedly. In addition, in order to enhance the insight in work-resumption, for which we identified solely one predictor other than complaints reduction, predictors reflecting more objective psychosocial characteristics may be assessed. Support for a better prediction of sickness absence by actual job demands and control rather than perceived job demands and control has been reported [
62]. Additionally, care-related indicators may be included, as other researchers reported that variables such as the number of consultations of the occupational physician or other caregivers, or communication between the supervisor and the occupational physician, were associated with work-resumption [
18,
61,
63].
In conclusion, this study is an initial step in analyzing the role of individual, work-related, and illness-related variables in recovery from work-related stress. It demonstrated that different predictors exist for complaint reduction and work-resumption, suggesting that complaint reduction and work-resumption are processes driven by different forces. However, the outcome that a reduction of burnout complaints preceded work-resumption illustrates that the processes of complaint reduction and work-resumption are to some extent related. Though, in need of cross validation, our results provide initial support for promoting work-resumption through targeting burnout complaints and use of a multidisciplinary treatment approach.