Work and mental health: what do we know and how can we intervene?

Print ISSN: 0355-3140 Electronic ISSN: 1795-990X Copyright (c) Scandinavian Journal of Work, Environment & Health Editorial Scand J Work Environ Health 2019;45(6):529-532 doi:10.5271/sjweh.3856 Work and mental health: what do we know and how can we intervene? by Rugulies R, Aust B Affiliation: National Research Centre for the Working Environment Lersø Parkallé 105, DK-2100 Copenhagen, Denmark. rer@nfa.dk Refers to the following texts of the Journal: 2018;44(3):239-25

Regarding the third theme -intervention studies aiming to protect and enhance workers' mental health -little is known about the key for success. It is therefore welcomed that in this issue of the Scandinavian Journal of Work, Environment and Health, three reviews either solely or partly focus on this topic.
Phillips and colleagues identified 50 randomized controlled trials using e-mental health interventions, including 34 of those in meta-analyses (18). The interventions focused on making changes in the individual, with about two-thirds based on cognitive behavioral therapy. The authors reported "moderate effects on stress, insomnia and burnout and small treatment effects on depression, anxiety, well-being, and mindfulness".
Bordado Sköld and colleagues conducted a systematic review on the effect of exercise interventions at work on either psychosocial working conditions or workers' mental health (19). The 22 included studies showed large heterogeneity in terms of study design, populations, interventions and outcome measures. Consequently, the authors did not calculate pooled estimates but performed a qualitative synthesis. Some studies reported improvements in mental health scores in the intervention groups, other studies did not find any effects. Overall, the results did not provide support for the hypothesis that workplace exercise programs may be beneficial for workers' mental health. There was also no convincing effect on psychosocial working conditions.
Proper & van Oostrom conducted a "meta-review" (a systematic review of previously published reviews) on the effect of workplace health promotion interventions on metabolic risk factors and musculoskeletal and mental health (20). They identified 23 reviews, including 9 of high quality. There was strong evidence for an effect of workplace health promotion programs on weight-related outcomes and the prevention of musculoskeletal disorders. Regarding mental health, Proper & van Oostrom identified 6 reviews, 4 of low and 2 of high quality. The interventions included e-mental health interventions, cognitive behavior therapy, stress management, psycho-education and physical activity. The authors conclude that there was strong evidence that e-mental health and cognitive behavior techniques had a positive effect on workers' mental health, whereas the evidence for intervention on physical activity was less clear, echoing the conclusions by Phillips et al (18) and Bordado Sköld et al (19).
What do we learn from these three reviews? First, interventions based on cognitive behavior therapy, including e-mental health interventions, seem to be an effective tool for protecting and enhancing workers' mental health (18,20). However, as Phillips et al noted (18), more than two-thirds of the participants in e-mental health studies were highly educated (having at least some years of university education), and jobs in knowledge-intensive occupational sectors, such as information technology, were overrepresented. Considering that mental disorders are more prevalent in individuals of lower socioeconomic position (21)(22)(23), one may be concerned that e-mental health interventions do not reach those who need help most. Further, it remains unclear if e-mental health intervention are as effective for workers with low education as they seem to be for workers with high education.
Second, exercise programs at work sometimes seem to have a positive effect on mental health and other times not (19,20), thus, no clear conclusion can be drawn. The reason for these inconsistent results are unknown as exploring these reasons was beyond the scope of the reviews (19,20).
Third, the interventions did not aim to change the work environment but rather the individual worker. In the review by Bordado Sköld (19) this was a given as the review was about exercise programs. But e-mental health interventions could have been about guidance for changing working conditions and workplace health promotion does not have to be limited to health behaviors and cognitive changes but could also target the work environment, as it has been proposed in the concepts of "Comprehensive Health Promotion" (24) and "Total Worker Health TM " (25). However, these type of interventions did not seem to have qualified for the review on e-mental health (18) or the meta-review on workplace health promotion (20).
A recent meta-review on "workplace interventions for common mental disorders" (26) identified -in agreement with the meta-review by Proper & van Oostrom (20) -cognitive behavioral therapy-based stress management as the intervention with the strongest evidence for a positive effect on workers' mental health. The only effective intervention regarding working conditions and mental health identified in this review were interventions to increase worker control (eg, self-scheduling of shifts and gradual/partial retirement) (26). However, the evidence was weaker than for cognitive behavioral therapy.

Editorial
Considering the above-delineated evidence for an association between adverse working conditions and the risk of developing mental disorders (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and the ongoing discussion about using work matched to one's "knowledge, skills and circumstances, and undertaken in a safe, healthy and supportive working environment" (13) as a therapeutic tool for individuals with prevalent mental health problems and disorders (13,(15)(16)(17), it is disconcerting that organizational-level, work environment interventions to protect or enhance workers' mental health seem either not to qualify for systematic reviews (18,20) or, if they do, show rather weak or inconsistent results (26,27).
One reason why organizational-level interventions have not shown convincing effects regarding workers' mental health may be that these type of interventions are highly dependent on the context in which they are implemented in (28,29). Consequently, researchers in this field have argued for no longer only asking "What works?", but instead "What works, for whom, under what circumstances, and how?" (30,31). It can be regarded as a sign of scientific progress that this question is now increasingly being posed, indicating the retreat of the idea that workplace organizational interventions can be evaluated in a similar way to those of clinical trials testing the efficaciousness of a new drug (32)(33)(34). However, the real progress that still needs to be made would be to find answers to the question "What works, for whom, under what circumstances, and how?", to report these answers in research articles, and finally to summarize these results in new types of systematic reviews and meta-analyses (35). Occupational mental health research has quite some way to go until we reach this stage.