Yoga versus transdiagnostic cognitive behavioural therapy for emotional disorders in community-dwelling adults: Study protocol for a non-inferiority randomised controlled trial

Cognitive behavioural therapy (CBT) is the first-line non-pharmacological intervention for the most prevalent and co-occurring mental health conditions (anxiety, major depressive, posttraumatic stress, and alcohol use disorders). However, CBT response rates are variable and access is limited by cost, availability, and up-take. Yoga demonstrates efficacy for these conditions and may be more accessible than CBT. However, to better refine personalised healthcare and ensure maximum generalisability to "real-world" presentations, we need methodologically robust randomised controlled trials (RCTs) that compare yoga to appropriate controls, monitor mental health co-occurrences, and examine biomarkers and mechanisms of action alongside outcomes. We present the study protocol for an ongoing, experimenter-masked, parallel-group, non-inferiority design RCT to evaluate the efficacy of 10-week yoga (novel intervention) versus 10-week transdiagnostic CBT (the Unified Protocol; evidence-based active control) for co-occurring anxiety, major depressive, posttraumatic stress, or alcohol use disorders among community-dwelling Australian adults (aged >= 18 years). The protocol is approved by Murdoch University Human Research Ethics Committee. The primary outcome measure is the Kessler Psychological Distress Scale (weeks 0, 11, 23, 35) and power analyses determined a minimum of 67 participants per group are required to assess non-inferiority. Secondary outcomes include a clinician-administered interview, self-reported symptoms, and functional outcomes. Sleep and emotion regulation self-report measures (including ecological momentary assessment) and physiological biomarkers (actigraphy, heart rate variability) will be tested as potential moderators and mediators of outcome. Experimenter-masked analyses will use both intent-to-treat and per-protocol approaches. Findings: will inform evidence-based formal recommendations and policy regarding the implementation of yoga into healthcare and may advance precision medicine.