4 - (OP31) Evaluation of a Translated and Culturally Adapted Internet-delivered Cognitive Therapy for Social Anxiety Disorder in Japanese Clinical Settings: A Randomized Controlled Trial

Cognitive therapy for social anxiety disorder (CT-SAD) based on the Clark & Wells model (1995) has strong empirical support and is recommended in several national clinical guidelines. However, access to evidence-based psychological treatments such as CT-SAD remains a global challenge. To address this issue, an internet-delivered version of CT-SAD (iCT-SAD) was developed in the UK and demonstrated clinical outcomes comparable to face-to-face CT-SAD while requiring substantially less therapist time in a randomized controlled trial (Clark et al., 2023). A subsequent randomized controlled trial conducted in Hong Kong reported outcomes comparable to those observed in the UK, suggesting that iCT-SAD can be successfully transported across cultures without a significant loss of efficacy (Thew et al., 2022).

However, the Hong Kong trials used the English version of iCT-SAD and included only English-speaking participants. Consequently, the clinical effectiveness of a translated and culturally adapted version of iCT-SAD in a non-English-speaking context, such as Japan, has not yet been established. Initial work demonstrated the successful translation of iCT-SAD into Japanese, incorporating minor but meaningful cultural adaptations where appropriate (Yoshinaga et al., 2021). A subsequent single-arm pilot study indicated good acceptability and preliminary evidence of strong efficacy of Japanese iCT-SAD for Japanese clients (Yoshinaga et al., 2023). These findings highlighted the need for a more rigorous evaluation through a randomized controlled trial.

The present randomized controlled trial aimed to evaluate the clinical efficacy of Japanese iCT-SAD when delivered in combination with treatment as usual (TAU) for Japanese clients with social anxiety disorder (SAD). Participants were randomly assigned in a 1:1 ratio to either Japanese iCT-SAD plus TAU or TAU alone. The primary outcome measure was the self-report Liebowitz Social Anxiety Scale. Secondary outcomes included additional measures of social anxiety symptoms and maintaining processes, general mood and functioning, and treatment response. Treatment acceptability and qualitative feedback from participants were also assessed. Assessments were conducted 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 plus TAU group.

As of December 2025, recruitment of 60 participants (iCT-SAD + TAU: n = 29; TAU alone: n = 31) was completed between February 2024 and October 2025. Outcome analyses and the collection of feedback from participants and their primary psychiatrists are currently underway, and the results will be presented at the conference. By evaluating the effectiveness of a culturally adapted Japanese version of iCT-SAD delivered alongside routine clinical care, this study is expected to provide important insights into the global dissemination and real-world implementation of internet-delivered cognitive therapy for social anxiety disorder.