Effectiveness of a Group-Based Psychological Safety Intervention to Prevent Workplace Bullying and Sustain Work Engagement: A Cluster Randomized Controlled Trial

Building psychological safety is vital for preventing workplace bullying and for sustaining employee well-being, organizational performance, and work engagement. This study developed and evaluated a short-term intervention promoting psychological safety and communication skills. The program provided strategies for addressing during high-stress situations and fostered a shared understanding of honest communication. A cluster randomized controlled trial was conducted in a pharmaceutical company, with departments assigned to intervention or control groups. The effects were examined using a generalized linear mixed-effect model. In the intervention group, psychological safety with supervisors and teams significantly increased, preceding a significant rise in consultation tendencies, whereas bullying and supervisor-related intimidation significantly decreased. Work engagement declined in the control group but remained stable in the intervention group. These findings demonstrate that the program enhanced psychological safety, enabling employees to express opinions without irrational fear, which in turn increased consultation, improved communication, reduced bullying, and sustained work engagement. The group-based format further emphasized mutual understanding and skill-sharing, providing broad organizational benefits. This study positions psychological safety as a proximal mechanism that facilitates consultation behaviors and demonstrates the feasibility of integrating brief, evidence-based training into routine organizational development.