Determinants of Sickness Absence and Return to Work Among Employees with Common Mental Disorders: A Scoping Review

In the earlier literature on work outcomes of people with a CMD, the focus of study was mainly on the prognostic value of the condition itself. Since we know that people with a CMD have higher odds to have problems with (sustainable) work participation, but the condition in itself provides an inadequate explanation, the research focus has become more on personal-, and environmental (e.g. work) related factors. The most relevant determinants for SA identified in our review, in terms of association and modifiability, are symptom severity, job demands and control, job strain, organizational (in)justice, sleeping problems, smoking behavior, and perceived general health. Individuals with a CMD with earlier episodes and a past history of absenteeism, who encounter high job demands, low job control, low support at work, sleeping problems, and low perceived health, are at high risk of SA.

There was consistent evidence that earlier episodes of CMD and high symptom severity are predictors for SA. From literature it is known that serious mental disorders are substantially underdiagnosed and undertreated among disability claimants [79, 94, 95], which is associated with inadequate availability and accessibility of care. Early recognition and diagnose of CMDs is very important, especially because interventions might prevent impairment of conditions and work disability. In the end, staying at work might be a powerful determinant for (mental) health of workers with a CMD [96]. However, symptom reduction due to psychosocial interventions is important, but is not a guarantee for reduction of sick-leave [97].

Although it is clear that having a CMD is related with SA, the causality of this relation is less obvious. Sanderson et al. reported that having a CMD was a consequence (and not a risk factor) of SA, limitations in work activities or unfavorable work environment [23]. In other studies, many workers believed that the most important causes of their CMDs were work related, and they reported factors such as work stress, leadership, reduced work participation, job dissatisfaction, work conflict, social work environment, job insecurity and change, workplace bullying, disrupted communication with supervisor, and physical strain [98, 99]. Therefore, preventive interventions for SA “should aim at decreasing psychosocial risk factors for the onset of CMDs at the workplace” [100].

There is consistent evidence that higher perceived job demands combined with low job control is related with SA of workers with CMD [31, 33, 34, 37, 43, 51, 55, 63]. A job with high decision latitude can largely neutralize the risk of high job demands. Therefore, interventions to prevent SA of workers with a CMD should involve the workplace [100]. Improving the work environment might not only prevent SA, it even may prevent the development of a CMD [98, 99].

Earlier episodes of CMD and having a past history of CMD-related SA is a predictor for future SA [24, 28, 38, 60], and therefore in the supervision of absent employees with CMDs more attention should be paid to previous episodes of mental illness. These workers at risk for future SA might be supported to stay at work, although account should be taken of stigmatization of workers.

Poor support or lack of support from the superior (positive feedback and appreciation of achievements) was observed as determinant of SA for workers with a CMD, it doubled the risk of absence for both genders [36]. The authors conclude that improving working conditions, such as social support, “may be an important step toward reducing the burden of SA due to mental conditions”.

The key determinants for RTW in workers with a CMD currently reported in the literature are symptom severity, duration of previous absenteeism, age, general health perception, bullying, social support from coworkers and supervisor, and positive expectations concerning sick-leave duration or RTW. For most environmental work related factors insufficient evidence was observed (Table 3).

Support from supervisor was variably associated with better work outcomes. Nieuwenhuijsen et al. concluded that supervisors should communicate more frequently with sick-listed employees with CMDs, and hold follow-up meetings more often, as this is associated with a faster RTW in those employees [68]. They advise supervisors to keep in touch with employees who are sick listed at least once every 2 weeks. However, promoting RTW by the supervisor had no effect, and consulting with professionals even had a negative effect on RTW. The explanation of the authors was that “supervisors may consult other professionals sooner if they foresee problems in the RTW-process” [68]. Patients with more social support from coworker or supervisor had a shorter time to RTW [80]. Other studies report no associations between supervisor support and SA [34, 55]. In a recent Swedish study, worse perceived interactional justice with the supervisor was associated with early RTW [82].

We found consistent evidence that the expectations concerning sick-leave duration or RTW are predictive for time to RTW, and may have a significant impact on the outcomes of interventions for RTW. Knowledge of workers’ expectations in the early phase of SA may contribute to shortening the time to RTW, and questioning workers about their expectations can serve as screening the risk of long-time SA [78]. Although expectations about sick-leave duration and RTW have predictive value, an explanation of these expectations should be examined in consultations with the individual employee. Workers’ expectations can be considered as a ‘canary in the coal mine’, and should give rise to a more detailed analysis of both individual- and work-related factors. Workers’ expectations are presumably based on the social context, the available social support both at home and at work, opportunities to realize work accommodations or to return to work gradually, and on the severity of illness. Nieuwenhuijsen et al. reported fatigue, suffering from depression, and workpace and workload as determinants for RTW perceptions [81]. Løvvik et al. reported a strong relationship between illness perceptions and RTW-expectations among people with CMD [101]. Addressing RTW-expectations in occupational healthcare services or vocational rehabilitation might be beneficial in early stages or even prior to a sick-leave episode [102]. Expectations for RTW [103] and self-efficacy [104] can be measured with a questionnaire, although the former needs further validation in a CMD population.

About 19–37% of employees with SA due to CMDs at baseline had recurrent episodes after RTW during two year follow-up [86, 92]. It is recommended to follow workers who just returned to work for a longer period and not take their return for granted, because many workers with a CMD have recurrences of SA. The oversight of determinants for recurrent SA does not provide much consistent evidence in favor of certain prognostic factors. This is mainly caused by the fact that most factors were studied only once. The number of previous episode(s) of SA [88, 91] and a shorter tenure [87, 88] were consistently related to recurrent SA. Interventions to prevent recurrence of SA in people with CMDs in order to sustain employees at work, may aim at detection of workers with previous episode(s) of SA and workers with a shorter employment relationship. Furthermore, it sounds reasonable that the predictors for SA may also apply for recurrent SA, and that these could be used too. In one study, it was observed that conflict with supervisor was a risk factor [90]. Obviously, not only the absence of social support from supervisor, but also the presence of negative relationships may affect SA.

This scoping review provides a clear overview of the existing empirical evidence about the prognostic factors of SA and RTW among workers with a CMD. A total of 71 articles were identified, which is a far greater range than previously known. The classification of these factors in ICF-domains across work outcomes facilitates retrieval of information and comparison with other research. The data was collected in a systematic manner and the probability of missing important literature is quite low. A strength of this scoping review was that we differentiated between three chronologically occurring work outcomes (SA, RTW, and recurrent SA), and that we presented all applied outcomes.

One general limitation of a scoping review is that no thorough quality assessment of retrieved studies is performed. In order to overcome this limitation, we only presented results established through multivariate analyses, which controlled for possible confounders [105], although the kind of treatment(s) that participants followed was controlled for in only a few of the included studies.

The time to follow-up in the vast majority of studies was sufficient (1 or more years). Although a few studies had a cross-sectional design, in these cases a retrospective data collection was performed on previous treatment, SA, or potential confounders. Another limitation of this scoping review was that CMDs were studied as one group where no distinction was made between different diagnostic groups, such as anxiety disorders and depressive disorders, which makes interpretation less specific. Moreover, in a few studies the exact amount of people with a CMD was unclear. Frequently, more articles were published based on the same cohort study. In these cases, it was not always clear to what extend the research data of these articles overlapped, which occasionally might have led to double reporting.

The majority of studies identified in the review were performed in the Netherlands or the Scandinavian countries. In Denmark, the first period of disability is paid by the local government, the municipalities. In the Netherlands and in Sweden, the employer bears responsibility for sustainable work participation and RTW of employees. In case of continued sickness or disability, Dutch workers get 100% pre-injury earnings compensated by the employer during the first year. This could have the effect that workers are not motivated to get back to work quickly. However, because the employer has incentives and legal obligations to support the absent worker, the possibilities to adapt the work to the needs of workers are utilized when necessary. Thus, in the Netherlands, Denmark and Sweden the employer or the government has an interest in preventing SA and promoting RTW, and initiates interventions to succeed. In this context, it is understandable that a boom of research on SA and RTW was initiated in these countries. However, the question is to what extent these results can be generalized to other countries. A compensation policy that provides for economic support in case of sickness or disability does not exist in all countries. Thereby, the propensity to take sick-leave or to return to work will differ across jurisdictions, even across Australian state and territory workers’ compensation systems [106]. In the USA, social security disability insurance taxes may discourage individual firms from investing in RTW. Likewise, the jurisdictions for CMDs as accepted cause of SA differ across countries. Therefore, it is not easy to draw general conclusions about predictive factors for SA or RTW, because a promoting factor in one jurisdiction might be a limiting factor in another.

Factors from the activities domain of the ICF framework are under investigated. Probably, researchers think that activity level is unimportant or not relevant in people with a CMD because they have no activity limitations. On the other hand, inactivity is an important symptom in CMDs and is not conducive to recovery [107]. From this point of view, the relation of (in)activity should be analyzed more in future research. In our review we identified two articles which studied the relation between physical activity and SA, of which one concluded that physical activity was related [40] and the other found no association [63]. There is currently not enough evidence to draw conclusions about activities-related factors as determinant for SA or RTW.

Salkever et al. are the only authors who focused their study on benefit plan features, such as availability of mental health benefits and services, employers’ disability management practices, and long-term disability policy provisions provided by the employer [66]. It was concluded that integration of disability management with related services, and providing job accommodations was related to a higher probability of RTW. Provision of more generous benefits in terms of lower deductible, shorter preexisting condition exclusion period, and not having a carve out encouraged earlier RTW. Employees having a broader criterion for continuing disability had a lower probability of RTW. Because the effect of benefit plan features was only studied by Salkever et al., the evidence was classified as insufficient. Notwithstanding, the results are interesting. It was observed that benefit plan features may play a role in the RTW trajectories of workers with CMDs. This study demonstrates that the benefit plan features, which may differ across companies, individuals, and even countries, could possibly affect SA and RTW. To what extent these results are also valid in other benefit systems in countries other than the USA, where jurisdictions and legislation are different, is still unclear.

Organizational justice was observed as determinant for SA in people with a CMD [50, 54]. In a largely representative sample of employees in the Netherlands, it was found that both distributive and procedural justice contributed to lower depressive symptoms, and distributive justice contributed to lower SA [108]. Perceived injustice in general might be an important determinant, which is already studied among people with musculoskeletal problems [109]. Emerging evidence suggests that perceived injustice might be a relevant factor for many people with chronic non-specific back pain and is considered as a determinant for work disability [109, 110]. The feelings of injustice may be directed against the employer, the insurer, co-workers, healthcare workers, occupational physician, or the person who performed a functional capacity evaluation. Because perceived injustice is likely related to depressive feelings [108, 111], it could be addressed in future research and practice of CMDs.

In a systematic review exploring illness perception in mental health utilizing the self-regulation model, it was concluded that the dimensions of the self-regulation model were largely supported, and applicable to mental illness [112]. We did not find sufficient evidence in our review about illness perceptions as predictor for work outcomes among people with CMDs. Illness perceptions are derived from the self-regulatory model of health behavior [113], which provides a framework for understanding the processes by which an individual’s own implicit, common-sense beliefs about illness are associated with behavioral responses employed to manage outcomes. Five dimensions of illness perceptions are distinguished: identity (the label of the illness and the symptoms the patient views as being part of the disease); cause (personal ideas about etiology); time-line (how long the patient believes the illness will last); consequences (expected effects and outcome of the illness); and cure/control (how one recovers from, or controls, the illness) [113]. Løvvik et al. found that illness perceptions predicted benefit recipiency in people with CMDs in the unadjusted model, but not in the fully adjusted model [114]. Results from a recent systematic review suggest that illness perceptions may play an important role in mediating between illness and work outcomes [115]. Although expectations about recovery as earlier described in our review is part of illness perceptions, there are more interesting aspects of illness perceptions mentioned above which have not been studied yet in CMDs.

To what extent are the prognostic factors in the present study congruent to the opportunities and obstacles mentioned to be important for work outcomes by the workers with CMD themselves? In a meta-analysis of qualitative research on RTW among employees with CMDs, a number of obstacles and facilitators were identified [116]. Perfectionist character made it difficult for employees to slow down their work pace and to accept reduced work capacity. The possibility to gradually RTW (increase working hours, responsibilities, and workload), the realization of work accommodations, and social support from both supervisors and co-workers were reported as important facilitators by employees. Attitudes of employers and co-workers towards sick-leave and development of CMD affected the motivation to return to work significantly. Perceived injustice may occur when understanding of CMD symptoms is lacking, and when work accommodations are not acknowledged and respected [116]. The right timing for RTW, in other words the readiness for RTW, was indicated as an important factor. In a qualitative study, the RTW process of workers on sick leave due to CMD was studied [117]. The main perceived barriers experienced by the workers were the inability to set limits, decreased capacity, recognition of exhaustion, lack of support, and to control cognitions and behavior such as perfectionism. Indicated solutions were learning a new way of dealing with work demands, and treating mental or physical symptoms. Furthermore, an intention-behavior gap was observed between the solutions and intentions to full RTW. According to the authors, having a positive attitude and increasing self-confidence by extending the workload carefully towards a full RTW are prerequisites for the intent to proceed.

In a Delphi study, group consensus was sought among scientists and physicians with expertise in assessing work disability on factors predicting recurrent SA due to depression [118]. Workers at risk of recurrent SA due to depression may be identified by stressful life and work events, number and duration of earlier depressive episodes, psychological work demands, decision latitude, and commitment to work.

In this scoping review we provided an oversight of prognostic factors for (recurrent) SA and RTW among people with a CMD. Further research is clearly required; there is a need for a systematic review or meta-analysis, in which the strength of prognostic values is investigated. The following factors are regarded as important by workers with CMDs and should be considered as subject for future primary research, because original primary studies are lacking: perfectionism, illness perceptions, acceptance of the illness and decreased work capacity, the possibility for gradual RTW and work accommodations, and perceived injustice. There is a need to develop more interventions to prevent SA and to improve RTW for workers with a CMD, and also to carry on studies that investigate its effectiveness. When future interventions are designed based on the known prognostic factors for SA and RTW, their effectiveness can potentially be improved.

More research on predictors for RTW in people with CMDs is needed in the ICF-domains ‘body functions and structures’, ‘activities’, and ‘environmental factors’. Concerning SA, RTW and recurrent SA, more research is needed on ‘environmental (work related) factors’, because the evidence in this domain was mostly insufficient as it came from only one study. Lastly, more research is needed on recurrent SA, because prognostic factors in the ICF-domains ‘disease related factors’, ‘body functions and structures’, and ‘activities’ were lacking.