Environmental and Occupational Health Practice
Online ISSN : 2434-4931
Field Studies
Development and application of a problem-solving approach to prevent sick leave owing to mental disorders in a manufacturing company
You Hwi Song Eiji Yano
Author information

2021 Volume 3 Issue 1 Article ID: 2021-0002-FS


Objectives: This study aimed to reduce the number of sick leaves due to mental disorders using a problem-solving approach as the primary preventive strategy. Methods: We developed the approach referring to evidence-based public health, community-based participatory research, and competencies of occupational health professionals. We then applied the approach step-by-step to occupational health practices in a manufacturing company. Results: For the problem statement (Step 1) and formulating a hypothesis of cause-and-effect relationships (Step 2), we conducted a case-series study and hypothesized several workplace factors as causes of sick leaves. For empirical analysis (Step 3), we performed a retrospective cohort study. We set a department as the intervention target because of the high prevalence of sick leaves. After finding contextual and translational evidence by searching the scientific literature and assessing scientific evidence (Step 4), we identified stakeholders and weak elements in the occupational health management system. We promoted partnership with the stakeholders by sharing our findings (Step 5). We then developed and prioritized intervention options (Step 6) within the partnership. The employer decided to strengthen those weak elements and address the causes of sick leaves by developing an action plan and implementing interventions (Step 7). The incidence of sick leaves has subsequently decreased in the department. Finally, we evaluated the effectiveness of the problem-solving approach on the system, program, and outcomes (Step 8). Conclusion: This study revealed that a problem-solving approach may be effective in preventing sick leaves due to mental disorders in the workplace by building infrastructure for occupational health practice.


Globalization and market liberalism are reflected in the changing structure and organization of work and employment. These changes have led to psychosocial risks and work-related stress, growing concerns for many workers worldwide1). The impact of mental health problems in the workplace has serious consequences not only for the individual employee but also for the productivity of the company2). Recently, acknowledgment of the important role of mental health in achieving global development goals has been increasing, as illustrated by the inclusion of mental health in the Sustainable Development Goals3). To address these occupational health concerns, prevention strategies need to be a combination of more holistic approaches to the occupational health system, rather than a single prescriptive approach1).

Supervisor education4) and worker participatory workplace improvement5) have been reported as primary prevention strategies to improve the psychosocial work environment.

A central challenge for occupational health practitioners is to translate the scientific evidence to action at a local setting. Thus, the conditions wherein these evidence-based interventions can be effectively implemented in the local setting may be clarified when the occupational health practitioners become aware of the mental health problems in their practice. For example, they may take action to enhance the employer’s decision-making, build assets and resources for the occupational health management system, and select and implement sustainable solutions.

Newell and Simon6) have stated: “a problem exists whenever a problem solver desires some outcome or state of affairs that he does not immediately know how to attain…Heuristics seldom provide infallible guidance…The theory of problem solving is concerned with discovering and understanding systems of heuristics”. A systematic problem-solving process may also be required in occupational health practice as guidance for future action. Problem solving is the act of defining a problem; determining the cause of the problem; identifying, prioritizing, and selecting alternatives for a solution; and implementing a solution. Problem solving is an important competency for occupational health professionals to prevent, maintain, and promote workers’ health.

This study aimed to reduce the number of sick leaves due to mental disorders by developing and applying a problem-solving approach as a primary preventive strategy to real occupational health practice in a manufacturing company and to clarify the contextual and translational factors for the effective implementation of programs or policies in the workplace.


We developed and applied a useful problem-solving framework to real occupational health practice in the company in a step-by-step manner.

Development and application of problem-solving approach

We considered the following three requirements for the useful problem-solving framework in real occupational health practice:

1) The flow of the framework should start with the “problem statement” and proceed to identify the cause of the problem using an epidemiological approach, because occupational health practitioners often become aware of the problem initially in their real practice.

2) Authorized competencies of occupational health professionals should be reflected in the flow of the framework. Occupational health practitioners should assess strengths and resources of the occupational health management system in the workplace and understand the context of the work organization and working culture to develop an effective program and policy to address this problem. They also must develop business management skills to be able to provide valid and competent advice to decision-makers in the workplace, such as senior management and worker representatives7).

3) Translating scientific evidence to action should be reflected in the flow of the framework because a focus on problem solving is expected in occupational health practice. Intentional dissemination and use of findings to benefit all partners are also needed. Diverse partners involved equitably would contribute their expertise and share responsibility to translate problem-solving ideas into action to improve workers’ health and well-being using a collaborative approach.

Eventually, we developed an approach to solve problems in the real occupational health practice, referring to principles and practices of evidence-based public health8), community-based participatory research9), and competencies of occupational health professionals10) (Table 1).

Table 1. Components, applied knowledge and actions of the Problem-Solving Approach for occupational health practice in the present study
StepComponents of Problem-Solving ApproachKnowledgeActions
Step 1Problem StatementEBPHInitial statement of problem by conducting case series study
Step 2Formulating hypothesis of X (causes)-Y (effects) relationshipEBPHFormulating hypothesis of X (causes)-Y (effects) relationship
Step 3Empirical AnalysisEBPHConducting epidemiological study
Step 4Searching the Scientific Literature and Assessing Scientific EvidenceEBPHSearching etiologic evidence (Type 1), intervention evidence (Type 2) and contextual or translational evidence (Type 3)
Step 5Management of the OH CompetenceCBPR/OHP ComtepenciesAssessing the OH strength, assets and needs, identifying and partnering with stakeholders and conducting OH teambuilding
Step 6Developing and Prioritizing Intervention OptionsEBPH/OHP CompetenciesIdentifying and choosing possible programs and policies by integrating scientific evidence, resutls of empirical analysis and assessment of
Step 7Developing an Action Plan and Implementing InterventionsEBPH/OHP CompetenciesSetting clear goals and objectives, clear role and responsibilities of stakeholders and OH team members, clear mechanisms for accountability and comprehensive plans with specific steps and timelines
Step 8Evaluating the effectiveness of the PSAEBPH/CBPR/OHP CompetenciesEvaluate outcome data, impact data, process data and formative data

CBPR, Community-Based Participatory Research; EBPH, Evidence-Based Public Health; OH, Occupational Health; OHP, Occupational Health Physician; PSA, Problem-Solving Approach.

To reduce the number of sick leaves due to mental disorders, we implemented a problem-solving approach to the occupational health practice step-by-step in a Japanese manufacturing company, which has approximately 30,000 employees dispersed at several offices, manufacturing plants, and small worksites.

Ethical statement

The objective of this field study is to indicate a methodology for investigating the causes responsible for workers’ health problems, which is one of the duties of an occupational health physician, as stipulated in the Industrial Safety and Health Regulations based on the Industrial Safety and Health Law in Japan. In addition, the empirical analysis in this study can be regarded as part of the duties, not under the category of research, because the data used in the analysis were obtained as per the regulations. Therefore, ethical approval for this field study was not required. This study was conducted with the approval of the joint safety and health committee of this manufacturing company. Written and signed consent was obtained from the company prior to submission.


We applied the problem-solving approach in a step-by-step manner to reduce sick leaves due to mental disorders in the workplace as follows:

Step 1: Problem Statement

Several young engineers taking sick leaves due to mental disorders were referred to YS (first author), who was assigned as an occupational health physician in the engineering department of the company.

The engineering department showed a higher incidence of sick leaves due to mental disorders compared with the rest of the company and a particularly increased incidence rate among young engineers. YS witnessed two cases of young workers in their twenties with sick leaves due to mental disorders. Moreover, YS encountered similar young workers with the same problem through health counseling at the same time.

These workers were male engineers with a university degree or more and full-time permanent contract position. They had an unremarkable medical history. They were suffering from symptoms of mental disorder including insomnia, appetite loss, and headache. All of them suffered from job stress due to high demand, long working hours (overwork; more than 45 hours per month), low control and support, and poor relationships. Two of them took sick leaves due to mental disorders for 6 months. One of them joined the company 4 years before the sick leave and moved to the engineering department 7 months before the sick leave, while the other started taking the sick leave in his second year with the company, 6 months after being assigned.

We analyzed 138 patients whose data were taken from interview records by the occupational health physician and identified a high-demand and harassment-permissive workplace atmosphere and poor human relations as distressing psychological factors that they experienced at all worksites of the company. Hence, we formulated a hypothesis of an association between sick leave and these risk factors at the company according to the next step.

Step 2: Formulating the Hypothesis of X (Causes)–Y (Effects) Relationship

In this step, we formalized the hypothesis of X (causes)–Y (effects) relationship based on the above case series and investigation for the next “Empirical Analysis” step. Initially, the X and Y in the hypothesis were conceptual based on the abovementioned case series and investigation. We then assigned operational X and Y variables for the “Empirical Analysis” step as follows:

● Conceptual X: Young, white-collar workers, job stress, poor human relations with supervisors, and unpleasant workplace atmosphere, such as harassment

● Conceptual Y: sick leaves due to mental disorders

● Operational X:

1. High stress determined in the Brief Job Stress Questionnaire (BJSQ) via the Stress Check Program in June of calendar year Z

2. Poor relationships with supervisors and unpleasant workplace environment, such as harassment, determined via the question added to the Stress Check Program in June of calendar year Z

● Operational Y: sick leave due to mental disorders for 7 days or more between July 1 of calendar year Z and March 31 of calendar year Z+1

Relationship with the supervisor and unpleasant workplace environment, such as harassment, were also investigated in this study using the following four questions:

- R1: “I scarcely communicate with my supervisor” (relationship with supervisors)

- R2: “I am reluctant to talk (much) to my supervisor” (relationship with supervisors)

- H1: “I have experienced bullying and harassment” (harassment)

- H2: “The workplace is permissive to harassment” (harassment)

To evaluate these factors, we used the 4-point Likert scale (ranging from 1=low to 4=high), reclassifying points 1 and 2 as “No” and points 3 and 4 as “Yes.”

Step 3: Empirical Analysis

The author conducted a retrospective cohort study in the company using data between April 1, Z-1 and March 31, Z+1. The duration of sick leave due to mental disorders as an outcome variable was defined as 7 days or more, with a medically certified mental disease diagnosis (International Statistical Classification of Disease and Related Health Problems, 10th revision-ICD-10, F00-99), taken between July 1, Z and March 31, Z+1. The diagnosis information of medical certification was obtained from the target company’s occupational health management registers.

High stress was determined in the BJSQ via the Stress Check Program in June of calendar year Z. Relationships with supervisors and unpleasant workplace environment were also investigated by questions originally added to the BJSQ in the company. The following variables were considered as risk factors for sick leave and were included in the analysis: age, sex, occupation, obesity, smoking, and sleep disturbance. We decided to exclude alcohol intake in our analysis because the available data was inaccurate. Subjects were asked about frequency of alcohol consumption in vague terms, such as “every day,” “sometimes,” and “rarely drink or cannot drink,” which is likely to include various meanings. They were also asked about the quantity of alcohol intake, but many people did not answer. The association between sick leave and stress profile was calculated in terms of odds ratio (OR) with 95% confidence interval (CI) using multiple logistic regression analyses.

The author found that subjects who were younger, were women, belonged to lower socioeconomic status, and experienced sleep disturbance availed significantly more sick leaves. The high stress determined in the BJSQ was not associated with the sick leave. In contrast, subjects who were reluctant to talk to their supervisors and those who perceived the atmosphere in the workplace environment to be permissive to harassment were significantly more likely to take sick leaves. These associations remained after adjusting for age and sex singularly and for age, sex, occupation, and sleep disturbance combined.

Step 4: Searching the Scientific Literature and Assessing Scientific Evidence

We analyzed organizational system, management system, and mental health program in the occupational health field according to the International Labour Organization’s “Guidelines on Occupational Safety and Health Management Systems”10) and the World Health Organization’s “Mental Health Policies and Programmes in the Workplace”11). Moreover, workers’ participation and safety and health committees were reviewed because they play important roles to prevent illness at the workplace12). We also applied principles of organizational behavior and project management to review the organizational system and stakeholders.

The company had a clear report of the duties that are historically and typically hierarchical features of the manufacturing industry (Figure 1). The organizations for safety and health management under regulation in the company were also well established. The company held a monthly safety and health committee meeting, and agenda and minutes of the committee were distributed to the entire organization, such as departments, sections, and staff. The management system also worked well to promote the workers’ health and safety continuously in the company. All levels of preventive strategies and division with roles responsible for the program were well established in the company. The mental health programs were: 1) primary prevention: improving hazardous work environment identified by the annual Stress Check; 2) secondary prevention: problem detection and referrals; and 3) tertiary prevention: reintegrating employees with mental health problems. The roles of employees, managers, and supervisors, occupational health staff, and external institutions were clarified. Education for employees did not include basic content, such as stress, stress coping, and the importance of consultation, but did include topics such as mindfulness, although opportunities for education and training for employees, managers and supervisors, and occupational health staff were secured. Coordination with external institutions was also established. Handling rules for health information have not been published in the company, although the information was handled properly based on the regulation of the personal information protection.

Fig. 1.

Analysis of the organization system and the Organization for Safety and Health Management in a manufacturing company.

shows the range consisted of key members in Company A Safety and Health Committee. Occupational Health Physicians are included in the SHM Organization of every plant. CEO, Chief Executive Officer; COO, Chief Operating Officer; CVP, Corporate Vice President; dpt, department; EVP, Executive Vice President; GM, General Manager; HR, Human Resources; SHM Organization, Organization for Safety and Health Management; SVP, Senior Vice President; VP, Vice President.

The engineering department did not hold their own organizational or management system for occupational health practice (Figure 1). The Japanese Industry Safety and Health Act required employers to set the organization for safety and health management and the safety and health committee at every business site based on the scale and industry specified by the act. The department did not have a legal obligation for installation, because the department was distributed over several business sites, and the number of employees at each site was small enough to be exempt from legal obligations. This led to a gap between their business report line and their organization for safety and health management that could hinder the implementation of problem-solving. In particular, the lack of worker participation as a democratic process, a feature of the management system in the field of occupational health, could not enable a rational improvement of the work environment, work organization, and work culture based on workers’ opinions.

Step 5: Partnership with Stakeholders

Generally, there are many stakeholders in occupational health practices, for example, employees and labor unions, employers, managers, and human resource departments, and other safety and health professionals10,11). We identified some stakeholders, including a person at senior management level and a general manager in the safety and health department (Figure 1). We noticed that a corporate vice president in the engineering department was a key stakeholder. Due to the lack of either its own safety and health committee or organization for safety and health management, he had not been briefed and was unaware of the mental health problems in the department.

We suggested a 30-min meeting with the corporate vice president wherein we would share the findings obtained from the Steps 1–4 with him. YS had already established a bridging human network with multiple occupations via the involvement of the occupational health management system and the safety and health committee, with multidisciplinary collaboration in case management for 8 years since the time YS was assigned as an occupational health physician at the manufacturing company. Therefore, it was considerably easy to obtain an appointment for a visit to the corporate vice president. YS applied a marketing theory13) for the communication strategy to anticipate his latent needs and foster his decision-making for problem solving. We conveyed our findings in the management context of labor loss, reduction of management efficiency, and risk of reputation loss owing to sick leave. The corporate vice president appeared to be shocked by those findings and promised to solve the problem together. We emphasized that worker participation as a democratic process was essential to improve the work environment, work organization, and working culture for promoting workers’ health in the field of occupational health. He decided to improve the dialogue between management and workers.

In addition, we discussed the immature educational system and health information handling rules with the general manager in the safety and health department, who was the supervisor of the safety and health management system in the company. He delegated his team members to reform the educational system and publish the health information handling rules.

Step 6: Developing and Prioritizing Intervention Options

We developed and prioritized intervention options within the partnership: 1) developing the organizational and management system, including worker participation, an educational system, and health information handling rules; 2) conducting programs and campaigns to decrease long working hours and improve human relations and workplace atmosphere; 3) evaluating the effectiveness of the interventions by monitoring the number of new sick leaves due to mental disorders after the intervention.

Step 7: Developing an Action Plan and Implementing Interventions

First, the corporate vice president introduced a new agenda related to safety and health for their weekly steering committee, consisting of himself and general managers in the departments (organizational system). He delegated his staff to interview young engineers and share the anonymous information, after qualitative analysis, in the steering committee (worker participation). He also monitored and reported the number of sick leaves to the steering committee (management system). The steering committee reflected the information to their business operation (management system). The corporate vice president began campaigns to improve overwork and human relations. The general managers alternately patrolled their offices and encouraged engineers to go home early. Moreover, they eliminated overwork by organizing job duties in their department, increasing the number of personnel, and partly outsourcing the duties. They also paid attention to the atmosphere and sent emails alerting staff not to yell in the workplace (program). Eventually, a project that included managers and young workers was implemented to improve their work environment, work organization, and working culture (worker participation). All the managers received training to improve their communication skills, especially active listening skills, to elicit valuable input from young workers. We consistently supported and empowered them to share leadership among the managers and workers in the engineering department.

We also collaborated with the general manager in the safety and health department and his team members to redesign the education system of mental health for employees and to develop health information handling rules. We reformed the context of the education for employees to understand basic knowledge, such as what stress is, how to cope with stress, and where the consultation counter is. Moreover, we published health information handling rules based on the regulation of the personal information protection after consulting with the labor union so that employees could consult with peace of mind.

Step 8: Evaluating the Effectiveness of the Problem-solving Approach

As the last step, we evaluated the effectiveness of the present intervention using the problem-solving approach. 1) Organizational and management system: the department succeeded in having their own mechanism for problem solving in the occupational health field by introducing its own organizational and management system, including worker participation. The reformed educational system and the new health information handling rules were also installed in the company. Partnership with a wide range of stakeholders was also developed. The development of these partnership and infrastructure has raised new research question and started new problem-solving approach projects. 2) Program: they conducted the programs organizing engineer’s duties, enhancing the work force, and partly outsourcing the duties. They also campaigned by patrol and email, alerting employees to reduce long working hours, and improved human relations and the workplace atmosphere. 3) Outcome: the number of the sick leaves due to mental disorders decreased in the engineering department, although the number among young engineers did not decrease clearly (Figure 2).

Fig. 2.

The number of sick leaves due to mental disorders in the engineering department. MD, mental disorders; PSA, Problem-Solving Approach; SL, sick leave.

a Japanese fiscal year is from April 1 to March 31.


We developed and applied the problem-solving approach to reduce the number of sick leaves due to mental disorders at the workplace. We conducted etiologic research, identifying the strengths and weak elements in the occupational health management system and involving diverse stakeholders as per the step-by-step problem-solving approach. All the partners shared the responsibility and leadership to conduct the preventive program for improving their work environment and enhancing the occupational health management system. Eventually, those actions not only reduced the number of sick leaves due to mental disorders but also developed infrastructure, such as worker participation, employer’s responsibility and accountability, a workplace educational system, and health information handling rules.

The following were the strengths of this process: 1) achieving a balance between research and action; 2) developing a democratic process even in a historically hierarchical organizational setting; and 3) building a sustainable system for occupational health by sharing responsibility and leadership with all the partners. These may contribute to culturally appropriate research and intervention strategies in the context of the organization.

Moreover, we added the specific step of partnering with stakeholders (Step 5) in the problem-solving approach. We considered the need to clarify the wide range of efforts to build the partnership because the partnership plays an important role in translating knowledge gained into action to improve community health and well-being9). We applied a marketing theory for the communication strategy. Marketing is the art of creating genuine customer value. If customers do not realize their true needs, smart marketers will attempt to anticipate the need rather than focus only on the current consumer wants13). Applying the theory for our communication strategy might help the corporate vice president to realize that sick leave due to mental health disorders is an important management issue in the business context. Multidisciplinary principles and practices for stakeholder engagement might be needed as a competency of the occupational health physicians6,7).

Nevertheless, some limitations must be noted. First, we could not collaborate with young workers who were directly involved. The manufacturing industry was a historically hierarchical organizational setting. Therefore, we emphasized to the management that worker participation as a democratic process was essential to improve occupational health. Eventually, worker participation was introduced, and a project comprising managers and young workers to improve the working environment was launched. Building of infrastructure might lead to sustainability of participatory actions by all the partners14).

Second, it may be difficult to generalize the findings from this research because the problem-solving approach was applied to a single manufacturing company. For example, our findings in the Step 3 empirical study were inconsistent with those reported by a previous study. In contrast to the study by Tsutsumi et al.15), we found no association between high stress as defined in the Japanese Stress Check Program and sick leave due to mental health issues. Type of industry, occupation of study subjects, and design of study were different between the two studies, which may have caused this inconsistency. However, our epidemiological approach using real-world data for identifying causes promoted the feasibility of the problem-solving approach in the local setting.

Third, our interventions have not produced thorough effectiveness and comparability. The number of sick leaves due to mental disorders did not decrease among young employees who were primarily targeted in the research, although the total number decreased in the engineering department. Longer-term observation and further intervention studies might be needed to evaluate the effectiveness of our interventions.

Despite those limitations, this study revealed that the problem-solving approach seems to reduce sick leave due to mental disorders in the workplace. Moreover, the problem-solving approach methodology might lead to sustainable participation action to protect workers’ health by building infrastructure for occupational health practice, with all partners involved equitably, which promotes a preventive culture in the workplace. Such integration of research and action may also need to be considered as an alternative to conventional biomedical research in real occupational health practice. We need further testing on the effectiveness of the problem-solving approach for other issues in varied settings.


The authors wish to thank Dr. Kazue Yamaoka, Professor of Teikyo University Graduate School of Public Health, and Dr. Kunio Hara, Professor of University of Occupational and Environmental Health for advice on study design, biostatistics analysis, and interpreting the significance of the results in this study.

Author contributions

Y.S. contributed to the design and implementation of the research, the analysis of results, and writing the manuscripts. E.Y. provided critical feedback and helped shape the research, analysis, and manuscript.

Conflict of interest

The authors declare that there are no conflicts of interest.

© 2021 The Authors.

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