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

Abstract

Introduction

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.

Methods

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.

Results

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.

Conclusion

Overall, results indicate that group tCBT for anxiety disorders shows equal effectiveness for GAD, PD/A, and SAD in real-world conditions.

Keywords:

• transdiagnostic
• CBT
• differential improvement
• anxiety disorders

Ethical approval

All participants have given their written informed consent that the study protocol was approved by the ethics review boards of the Integrated Health and Social Services Centers in Estrie (#MP-22-2016-570), Québec City (#2017-166) and Laval (#2016-2017-C54).

Author contributions

Norton and Rostami had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Concept and design: Norton, Provencher, and Roberge. Acquisition, analysis, or interpretation of data: Norton and Rostami. Drafting of the manuscript: Norton and Rostami. Critical revision of the manuscript for important intellectual content: Provencher and Roberge. Statistical analysis: Rostami and Norton. Obtained funding: Roberge, Provencher, and Norton. Study supervision: Roberge and Provencher.

Disclosure statement

PJN receives royalties from Guilford Press for the treatment manual used in the parent trial. All other authors declare no competing interests.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

The Canadian Institutes of Health Research funded this study (CIHR Grants #334091 and 340410).