Comparison of mindfulness training and acceptance and commitment therapy in a workplace setting: results from a randomized controlled trial.

Mindfulness interventions have become a common feature of worksite stress management provision. However, the evidence underpinning these interventions continues to attract scrutiny, with unresolved questions surrounding: the generalizability of mindfulness research findings to real-world workplace training applications, comparability of different mindfulness approaches offered in workplace settings, and effects on job performance. The current trial contributes to the literature by exploring effects of mindfulness training (MT) and acceptance and commitment therapy (ACT), which were delivered to staff in the same healthcare organization. Participants were randomly assigned to a 4-session MT program (n = 63), a 4-session ACT program (n = 67), or a waiting list control group (n = 69). Study measures were administered on five occasions spread across a 6-month period. Results indicated that both MT and ACT reduced perceived stress and improved mindfulness and sleep quality when compared to the control group. ACT showed slight superiority in helping employees align their behaviour with personal values. Neither MT nor ACT was effective in reducing work limitations. We consider explanations for equivocal effects on job performance outcomes, and highlight the importance of testing the effectiveness of worksite mindfulness interventions under ecologically valid conditions.