Translated and culturally adapted internet-delivered cognitive therapy for social anxiety disorder in Japanese clinical settings: study protocol for a randomised controlled trial

Cognitive therapy for social anxiety disorder (CT-SAD) has extensive empirical support and is recommended in several national guidelines. However, ensuring access to evidence-based psychological therapies such as CT-SAD remains a global challenge. An internet-delivered version of this treatment protocol (iCT-SAD) has recently been developed in the UK as a way to overcome this challenge, demonstrating comparable outcomes to face-to-face CT-SAD whilst requiring less therapist time per client. Initial findings also suggest its cross-cultural transferability, but the previous studies in other cultural settings used the English language programme and only included English-fluent participants as a second language. It is not yet known what outcomes can be achieved once the programme has been translated and adapted for a different cultural context. Therefore, this trial aims to evaluate the clinical efficacy of Japanese iCT-SAD when combined with treatment as usual (TAU) in clients with SAD.

This two-arm, parallel-group, superiority randomised controlled trial will recruit 60 Japanese participants with SAD, randomly assigning them to either Japanese iCT-SAD + TAU or TAU alone at a ratio of 1:1. The primary outcome measure is the self-report Liebowitz Social Anxiety Scale, and secondary.outcomes include other measures of social anxiety symptoms and processes, general mood and functioning, and response to treatment. We will also assess treatment acceptability and gather participant feedback. Assessments will take place at baseline (week 0), mid-treatment (week 8), and post-treatment (week 15), with a further 3-month follow-up (week 27) for the iCT-SAD + TAU arm. The primary analyses will be conducted on an intent-to-treat basis, comparing the primary and secondary outcome measures between groups using linear mixed-effect models, along with additional mediation analysis.

Investigating the efficacy of translated and culturally adapted iCT-SAD in different cultural contexts is an important step in evaluating the global reach of internet interventions. This trial will provide valuable insights into the effects of iCT-SAD combined with usual care, and how this treatment could be delivered in routine clinical settings in Japan.

International Standard Randomized Controlled Trials (ISRCTN), ISRCTN82859645, registered on January 19, 2024. UMIN Clinical Trials Registry (UMIN-CTR), UMIN000052702, registered on November 6, 2023.