Introduction Adverse psychosocial work factors are recognised as a significant source of psychological distress. The Healthy Enterprise Standard (HES) targets four intervention areas: Lifestyle, Work-life balance, Workplace environment and Management practices; this latter area referring to interventions aimed at improving the psychosocial work environment. The aim of this study was to evaluate the impact of implementing the HES on exposure to adverse psychosocial work factors and the prevalence of psychological distress among ten Quebec organisations.

Methods This was an intervention study with a before-after design derived from secondary data. Organisations adopted the standard of their own initiative and were responsible for implementing interventions. All active employees were solicited to participate before (T1=2849) and 24–38 months (T2=2560) following the standard’s implementation. At both time points, participants completed a questionnaire. Psychosocial work factors were assessed with the validated demand-control-support and effort-reward imbalance models. Psychological distress was assessed with the validated K6. Intervention exposure was measured by questionnaire and complemented by qualitative analyses.

Result The prevalence of low social support at work and high psychological distress decreased among all participants between T1 and T2. In organisations that were less exposed to interventions in the Management practices area, an increase in the prevalence of several adverse psychosocial work factors was observed while a decrease in the prevalence of these adverse factors was observed in organisations more exposed to Management practices interventions. Moreover, a more important decrease in high psychological distress was observed in organisations more exposed compared to those less exposed to interventions in this area.

Discussion These results suggest that organisational psychosocial interventions implemented in the context of this standard may be effective in reducing both adverse psychosocial work factors as well as high psychological distress and may therefore be an effective means to improve the mental health of workers.