The longitudinal mediating effect of distress tolerance in a mindfulness-based intervention: a randomized controlled trial

Objective: The present study aimed to investigate the intermediary role of distress tolerance in Mindfulness-Based Intervention (MBI) with respect to self-perceived stress reduction. Method: One hundred and twenty-nine adults with a high level of emotional distress were randomized into MBI groups or a waiting-list group. Levels of mindfulness skills, self-perceived stress, and distress tolerance (tolerance, appraisal, absorption, and regulation) were measured four times: pre-test, week 3, week 6, and post-test. Results: The developmental trajectories modeled by the univariate latent growth curve showed that the factor intervention significantly predicted the slope of observing, non-reactivity, overall mindfulness, and distress appraisal during first six weeks. Bivariate latent growth curve models demonstrated a significant association between increases in the growth rate of distress appraisal and non-reactivity in participants receiving mindfulness training. Such an association was not observed among those who did not receive an MBI. Longitudinal mediation analyses further revealed that the effect of MBI on non-reactivity and self-perceived stress at week 6 was fully mediated by distress appraisal at week 3, respectively. Conclusions: Our results indicate that distress appraisal plays an important role during the earlier stage of MBI, which might contribute to a more effective and efficient intervention program in the future.