Ten trials were included (n=671): seven RCTs; two controlled trials; and one uncontrolled trial. Study quality was generally low; Jadad scores ranged from 0 to 3. Only one of the controlled trials scored 3 and was rated as high quality. One open label uncontrolled trial was evaluated on the Newcastle-Ottawa scale and scored 0. Across the trials, specific issues were related to small sample sizes, self-selection in some of the trials, non randomisation and the difficulty of blinding.
MBSR for the reduction of stress (seven trials): MBSR had a significant positive effect compared to waiting-list treatment (0.743 +/- 0.77 versus -0.208 +/- 0.21, t=21.01, p≤0.001). Analysis restricted to RCTs showed similar results. One trial compared MBSR and active treatment and did not show any statistically significant differences between treatments.
MBSR for the enhancement of spirituality (five trials): MBSR was statistically significantly superior to inactive control (0.824 +/- 0.83 versus -0.043 +/- 0.37, t=9.95, p=< 0.000001). Analysis restricted to RCTs showed similar results. One trial compared MBSR with relaxation training and found no statistically significant differences on the INSPIRIT measure.
Further results from individual studies were reported for the secondary outcomes.