Effects of mindfulness-based stress reduction intervention on psychological well-being and quality of life: is increased mindfulness indeed the mechanism?

BACKGROUND: Although several studies have reported positive effects of mindfulness-based stress reduction (MBSR) intervention on psychological well-being, it is not known whether these effects are attributable to a change in mindfulness. PURPOSE: The aim of this study is to compare the effects of MBSR to a waiting-list control condition in a randomized controlled trial while examining potentially mediating effects of mindfulness. METHODS: Forty women and 20 men from the community with symptoms of distress (mean age 43.6 years, SD = 10.1) were randomized into a group receiving MBSR or a waiting-list control group. Before and after the intervention period, questionnaires were completed on psychological well-being, quality of life, and mindfulness. RESULTS: Repeated measures multiple analysis of variance (MANCOVAs) showed that, compared with the control group, the intervention resulted in significantly stronger reductions of perceived stress (p = 0.016) and vital exhaustion (p = 0.001) and stronger elevations of positive affect (p = 0.006), quality of life (p = .009), as well as mindfulness (p = 0.001). When mindfulness was included as a covariate in the MANCOVA, the group effects on perceived stress and quality of life were reduced to nonsignificance. CONCLUSION: Increased mindfulness may, at least partially, mediate the positive effects of mindfulness-based stress reduction intervention.