An analysis of differential improvement by diagnosis in group transdiagnostic cognitive behaviour therapy for anxiety disorders.

Anxiety disorders are the most prevalent among the mental health disorders and have a negative impact on an individual's life. Cognitive behaviour therapy (CBT) is documented as the most effective treatment for anxiety disorders. However, challenges associated with implementing diagnosis-specific CBT have led to transdiagnostic approaches of CBT (tCBT). tCBT uses a single protocol with core elements of CBT for treatment of anxiety disorders broadly. The aim of the current study is to examine whether participants with different principal anxiety diagnoses demonstrate similar anxiety reduction. The current study involved a secondary analysis of 117 participants randomly allocated to receive tCBT for anxiety disorders in a pragmatic randomised effectiveness trial. Beck Anxiety Inventory (BAI) and Clinician Severity Ratings (CSR) scales were administered at pre- and post-treatment and one-year follow-up, while the Anxiety Disorder Diagnostic Questionnaire – Weekly (ADDQ-W) was administered each session. Mixed-factorial analyses of variance (ANOVAs) indicated that participants with GAD, SAD and PD/A improved to post-treatment and maintained to follow-up, with no differential improvement across principal diagnoses. Mixed effect regression modelling of session by session measures indicated non-differential negative slopes across principal diagnoses of GAD, SAD and PD/A. Overall, results indicate that group tCBT for anxiety disorders shows equal effectiveness for GAD, PD/A, and SAD in real-world conditions. [ABSTRACT FROM AUTHOR]