Isolating the Effects of Mindfulness Training Across Anxiety Disorder Diagnoses in the Unified Protocol

The Unified Protocol for Transdiagnostic Treatment (UP; Barlow et al., 2011) has recently demonstrated statistically equivalent therapeutic effects compared to leading cognitive behavioral therapy (CBT) protocols for anxiety disorders designed to address disorder-specific symptoms (i.e., single-disorder protocols [SDP]); Barlow et al., 2017). Although all treatment protocols included similar evidence-based CBT elements, investigation of those related to symptom improvement in the UP is warranted. Because the UP is unique from the SDPs for its inclusion of mindfulness, the present study evaluated mindfulness as a primary treatment element. We explored whether UP participants, compared to SDP, demonstrated greater improvements in mindfulness from pre- to posttreatment, and whether these improvements predicted posttreatment severity across anxiety disorder diagnoses. Participants were individuals with a principle anxiety disorder (N = 179) randomized to receive either the UP or SDP. Results indicated significant improvements pre- to posttreatment in mindfulness for participants receiving either the UP or SDP. However, at posttreatment, mindfulness scores were significantly greater for the UP condition. At the diagnosis level, posttreatment scores in mindfulness were significantly greater in the UP condition than the respective SDP conditions for principal Generalized Anxiety Disorder (GAD) and Social Anxiety Disorder (SOC). Moreover, results suggest that change in mindfulness is related to posttreatment severity, when moderated by treatment condition, but only for participants with principal GAD. Taken together, the UP is effective in improving mindfulness in a sample with heterogeneous anxiety disorders, but this change seems particularly relevant for reduction in symptom severity for individuals with principal GAD.