Effectiveness of a one-year teacher training program in delivering school-based mindfulness on schoolteachers' mental health: A nationwide cluster-randomized trial

The nationwide Stress-free Everyday Life for Children and Adolescents Research (SELFCARE) project, conducted from 2019 to 2020 in Denmark included a structured, three-part mindfulness-based teacher training program implemented over one year. The current study aimed to evaluate the teacher program's effectiveness on teachers' self-reported mental health 12 months post-baseline. In this cluster-randomized trial, 110 schools were randomized 1:1 into either an intervention group of 54 schools and 97 teachers (mean age 46.2 years (SD 8.7), 10 males (10.3 %)) or a wait-list control group of 56 schools and 94 teachers (mean age 44.2 (SD 8.1), 6 males (6.4 %)). Mental health outcomes were assessed using three validated self-report measures, with the Perceived Stress Scale as the primary outcome. Nine additional self-report measures evaluated mental health skills, with the Brief Resilience Scale as the primary measure. Intention-to-treat analyses were performed using mixed-effects linear regression models and bootstrapping as well as sensitivity analyses. Follow-up data were collected from 57 teachers (mean age 48.1 (SD 7.9), 6 males (10.5 %)) in the intervention group and 65 teachers (mean age 44.7 (SD 7.8), 5 males (7.7 %)) in the control group. The intervention yielded a small but statistically significant reduction in perceived stress (Cohen's d = -0.38; 95 % CI: -0.75 to -0.01), while no significant effect was observed for resilience (Cohen's d = 0.12; 95 % CI: 0.12 to 0.34). Overall, the findings suggest that a mindfulness-based teacher training program could be an effective way of promoting mental health among self-selected schoolteachers, particularly with regard to reducing perceived stress in the long term.