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. Conclusions Increased mindfulness may, at least partially, mediate the positive effects of mindfulness-based stress reduction intervention.