The objective of the current study, Vital@Work, is to keep employees in the Netherlands vital on the long term by preventing work-related mental health problems. Therefore, we test an evidence based Participatory Approach (PA) to compose a mental health program tailored to behavioral, organizational & contextual (BOC) determinants of individuals and populations at risk. The PA is investigated in four different organizations, which differ in sector, size (small and large organizations), type of organization (private or public) and type of work. The varied organizations, each characterized by unique BOC-determinants, provide an opportunity for researching tailored intervention activities that aim to effectively prevent work-related mental health problems. By identifying common factors across these diverse organizations, we aim to grasp patterns of mechanisms for interventions to mental health at work. By doing this, we come closer to opening black box of how and why interventions work and thus closer to tailoring interventions to needs of both individuals and organizations

This study evaluates the PA as a strategy to implement measures to prevent or reduce work-related mental health problems by a cluster randomized controlled trial, including an intervention and control group. Employees in departments allocated to the intervention group receive the PA intervention in addition to the existing range of preventive mental health measures within the organization. Departments assigned to the control group receive standard practice and therefore only the existing range of preventive interventions will be highlighted and further drawn to the attention of employees (without the PA intervention). Due to the PA intervention and associated activities, it is not possible to blind the researchers and department managers. However, employees in the departments randomized to the intervention or control group are not aware of the research design. Only department managers are informed about the research design and the outcome of randomization, and they are asked not to communicate the research design to the employees.

The PA consists of six steps: 1) preparation: create prerequisites and initiate the PA, 2) risk assessment: analysis of bottlenecks and risks 3) solutions: Analysis of potential solutions 4) action planning: jointly formulating a plan of action to realize solutions 5) implementation: implementing measures by means of the action plan and 6) evaluation: evaluation of the approach.

For each intervention group, a participatory working group will be established, comprising 5-7 employees, a department manager/supervisor, a health and safety coordinator, an HR representative, and a communication specialist. Each intervention group is coordinated by a process facilitator who is responsible for preparing the meetings with the working group and leading the discussions during these sessions. To prepare individuals for this role, the process facilitator receives training, provided by researchers experienced in the PA.

The participative working group will go through steps 2 to 4 of the PA during a day session, resulting in an action plan for the intervention activities to be implemented. Subsequently, this action plan will be implemented throughout the entire team comprising the intervention group. This implementation process will be led by the process facilitator, supported by change agents. Ideally, (some of) the working group members will act as change agents. Change agents have the task of implementing interventions as widely as possible within the department and ensuring a smooth implementation process so that employees actually make use of the innovations. In order to act as catalysts for the implementation process within the department, the change agents and the process facilitator are trained by researchers experienced in the PA. The duration of the entire implementation period is approximately 12 months, but depends on the selected intervention activities, with short-term implementations lasting < 3 months, and long-term implementations lasting > 3 months.

Inclusion Criteria:

• Inclusion will be done on cluster level (e.g. team or department), after discussing this with participating organizations. The inclusion criteria for participation in the study comprise being at least 18 years of age, holding an employment contract with the participating organization.

Exclusion Criteria:

• The exclusion criteria include being under 18 years old, not being part of the participating teams/departments, or not having an employment contract with the participating organization.

Due to the PA intervention and associated activities, it is not possible to blind the researchers and department managers to the condition they are assigned to. However, employees in the departments randomized to the intervention or control group are not aware of the research design. Only department managers are informed about the research design and the outcome of randomization, and they are asked not to communicate the research design to the employees.