Long-Term Effectiveness of a Stress Management Intervention at Work: a 9-Year Follow-Up Study Based on a Randomized Wait-List Controlled Trial in Male Managers

Abstract

Objective: Short- and medium- term effectiveness (up to 3 years) of individual level stress management interventions (SMI) in the workplace were demonstrated, yet long-term effectiveness remains unexplored. We therefore aimed to address this research gap. Methods: 94 male middle managers participated in a randomized wait-list controlled trial between 2006 and 2008, and in a post-trial-follow-up survey in 2015. All received an 18-hour SMI during the first two years. The SMI included two intervention measures tightly based on the Effort-Reward Imbalance (ERI) model: stressor identifying and coping intervention for mismatch between effort and reward; and recovery intervention for over-commitment. The intervention used a group psychotherapeutic approach including psychodynamic and cognitive-behavioural techniques. Work stress in terms of ERI indicators was the primary outcome, and the secondary outcome was depressive symptoms. The long-term effectiveness of the SMI was examined by mixed modeling, using an external control group (n=94) with comparable characteristics. Results: Compared to the external control group, effort and reward were substantially improved, showing significant intervention*time interaction effects (p < 0.001). Though the trajectory of over-commitment and depressive symptoms in the intervention group was less sustainable, significant long-term effects were also observed in comparison with the external control group (p < 0.05 and p < 0.01, respectively). Conclusions: The effectiveness of a SMI at work based on the ERI model and on psychotherapeutic approaches was observed over a 9 year period, particularly on the effort-reward ratio.