# Internet‐Based Acceptance and Commitment Therapy With Interoceptive Exposure for Panic Disorder: A Randomized Controlled Trial and Working Alliance Analysis

## TL;DR

An internet-based therapy program with interoceptive exposure effectively reduces panic disorder symptoms, especially for those with agoraphobia.

## Contribution

Modified internet-based Acceptance and Commitment Therapy with interoceptive exposure shows significant efficacy for panic disorder.

## Key findings

- The treatment group showed a large effect size (d=0.92) in reducing panic disorder symptoms.
- 43% of participants no longer met diagnostic criteria for panic disorder post-treatment.
- Participants with agoraphobia had larger treatment effects despite higher initial symptom scores.

## Abstract

This study's primary aim was to evaluate the efficacy of an internet‐based Acceptance and Commitment Therapy (IACT) program modified to include interoceptive exposure for treating panic disorder with or without concurrent agoraphobia. Its secondary aim was to examine whether therapist‐ and client‐rated working alliances were related to treatment outcomes. This randomized controlled trial included 79 participants, assigned to either a treatment group (n = 40) or a waitlist control group (n = 39) over 10 weeks. The study investigated the effects on panic disorder and quality of life, as well as the relationship between working alliances (rated by therapists and clients) and treatment outcomes. At post‐treatment, there was a significant between‐group treatment effect on panic disorder symptoms, with an observed effect size of d = 0.92. The model‐predicted effect size based on the multilevel model was d
GMA‐raw = 0.86. Furthermore, 43% of participants no longer met the diagnostic criteria. Participants with concurrent agoraphobia exhibited higher initial panic symptom scores and were less likely to be diagnosis‐free post‐treatment. However, they still experienced significant and large treatment effects, with an observed effect size d = 1.22 and d
GMA‐raw = 0,99. There was no significant between‐group difference in quality‐of‐life measurements. The therapist‐rated working alliance was associated with treatment outcome, but no significant relationship was found for the client‐rated alliance. Overall, the study suggests that interoceptive exposure‐modified IACT is an effective treatment for panic disorder and shows promise for patients with concurrent agoraphobia.