Abstract
BACKGROUND: Anxiety disorders are the most common mental disorders in community settings, and they are associated with significant psychological distress, functional and social impairment. While cognitive behaviour therapy (CBT) is the most consistently efficacious psychological treatment for anxiety disorders, barriers preclude widespread implementation of CBT in primary care. Transdiagnostic group CBT (tCBT) focuses on cognitive and behavioural processes and intervention strategies common to different anxiety disorders, and could be a promising alternative to conventional CBT. This study aims to examine the effectiveness of a transdiagnostic group CBT for anxiety disorders program as a complement to treatment-as-usual (TAU) in primary mental health care. METHODS/DESIGN: The trial is a multicentre pragmatic randomized controlled trial with a pre-treatment, post-treatment, and follow-up at 4, 8 and 12-months design. Treatment and control groups. a) tCBT (12 weekly 2-h group sessions following a manualized treatment protocol); b) TAU for anxiety disorders. Inclusion criteria comprise meeting DSM-5 criteria for primary Panic Disorder, Agoraphobia, Social Anxiety Disorder and/or Generalized Anxiety Disorder. Patients are recruited in three regions in the province of Quebec, Canada. The primary outcome measures are the self-reported Beck Anxiety Inventory and the clinician-administered Anxiety and Related Disorders Interview Schedule for DSM-5 (ADIS-5); secondary outcome measures include treatment responder status based on the ADIS-5, and self-reported instruments for specific anxiety and depression symptoms, quality of life, functioning, and service utilisation. STATISTICAL ANALYSIS: Intention-to-treat analysis. A mixed effects regression model will be used to account for between- and within-subject variations in the analysis of the longitudinal effects of the intervention. DISCUSSION: This rigorous evaluation of tCBT in the real world will provide invaluable information to decision makers, health care managers, clinicians and patients regarding the effectiveness of the intervention. Widespread implementation of tCBT protocols in primary care could lead to better effectiveness, efficiency, access and equity for the large number of patients suffering from anxiety disorders that are currently not obtaining evidence-based psychotherapy. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02811458 .