Clinical Significance of Stress, Depression, Anxiety, and Worry Symptom Improvement Following Mindfulness-based Stress Reduction

Mindfulness-based stress reduction (MBSR) teaches mindfulness meditation to reduce stress, anxiety, depression, and related forms of distress among a variety of patients. Much research has documented statistically significant reductions across a variety of self-report measures following MBSR, but researchers rarely assessed and reported the clinical significance of MBSR symptom reduction in accordance with specific criteria famously established by Jacobson and Truax [1]. Patients reporting symptoms of anxiety, depression, and/or other stress-related concerns received MBSR in an outpatient mental health clinic. In order to assess the clinical significance of reported symptom reduction, specific criteria to determine reliable clinical improvement and recovery were applied to the data from each patient across the main symptom outcome measures. This secondary clinical significance analysis was conducted with all 23 patients who completed MBSR and completed assessment measures both before and after the intervention in the original open trial. A reliable change index and a cutoff point for outcome measures of worry, depression, anxiety, and stress were obtained so that reliable clinical improvement and recovery on each measure could be assessed for each patient. The proportion of patients who were elevated in the clinical range above the cutoff before the intervention was determined, as well as the proportion of those reporting symptom reduction, the proportion showing reliable improvement, and the proportion recovered at the final MBSR session. Clinical significance analyses revealed that over half of the patient sample scored in the clinical range on each measure before MBSR. At the end of the intervention, the vast majority of these patients reported symptom reduction, and depending on the measure, 45-69% of patients who were clinically elevated initially and reported symptom reduction following MBSR exhibited reliable clinical improvement. Furthermore, 29-50% of those patients showing reliable clinical improvement also met criteria as recovered at the conclusion of the MBSR program. These results suggest that the symptom reduction observed following MBSR is substantial and clinically meaningful for many patients – an outcome that cannot be determined with statistical tests of significance alone. Clinical significance criteria, such as those applied in this study, could be implemented in randomized controlled trial protocols to supplement conventional tests of statistical significance and shed light on how clinically meaningful obtained changes on outcome measures are for patients.