A Three-Arm Randomized Clinical Trial Comparing the Efficacy of a Mindfulness-Based Intervention with an Active Comparison Group and Fluoxetine Treatment for Adults with Generalized Anxiety Disorder

Introduction: Mindfulness-based interventions have been studied as an alternative treatment for anxiety disorders, but there are only a few studies comparing these with established treatments. Objective: To evaluate the efficacy of a Body in Mind Training (BMT) program for adults with generalized anxiety disorder (GAD), an active comparison protocol called Quality of Life and Psychoeducation (QoL), and treatment with fluoxetine (FLX). Methods: This study comprises a 3-arm parallel-group, randomized clinical trial (ClinicalTrials.gov ID: NCT03072264). Adults with a primary diagnosis of GAD and no current treatment were recruited from the community and randomized in a ratio 1:1:1. The primary outcomes were assessed by means of the Hamilton Anxiety Rating Scale (HAM-A) and the Penn State Worry Questionnaire (PSWQ) at week 8. Data were analyzed using a superiority analysis (BMT vs. QoL) and a noninferiority analysis (BMT vs. FLX). Results: A total of 249 participants were included and 223 were analyzed (76 BMT, 79 FLX, and 68 QoL). All groups improved after intervention. However, BMT was not superior to QoL at week 8 (mean difference = –1.36; p = 0.47), nor was it noninferior to FLX as assessed with theHAM-A (mean difference = 3.5; 95% CI –0.06 to 7.06; noninferiority margin = –2.43; p = 0.054). QoL (mean difference = 3.54; p = 0.04) and FLX (mean difference = –7.72; 95% CI –10.89 to –4.56; noninferiority margin = –2.09; p < 0.001) were superior to BMT in reducing PSWQ score. Conclusion: Our data suggest that BMT, in its current format, cannot be considered an effective mindfulness protocol to improve GAD.