User Experience and Clinical Utility of a Smartphone-Based Application for Hwa-Byung Treatment: a protocol for a single-arm prospective pilot study

Objectives: Hwa-byung (HB) is a Korean culture-bound syndrome characterized by suppressed anger and somatic symptoms, which affects a substantial proportion of the population and significantly impairs quality of life.While the Korean medicine clinical practice guideline for HB recommends mind-body therapies and psychotherapy as key interventions, their implementation in conventional clinical settings is limited by time, spatial barriers, and challenges in maintaining treatment continuity.Digital health technologies, particularly smartphone applications, offer accessible, personalized, and sustainable therapeutic solutions to address these challenges.Therefore, this study aims to evaluate the user experience and preliminary clinical utility of a smartphone-based stress management application in patients with HB through a single-center, single-arm, prospective intervention study.Methods: Based on acceptance and commitment therapy (ACT) principles and HB clinical practice guidelines, the Hwa-free application integrates four primary components: ACTbased educational videos, daily three-line journaling, diaphragmatic breathing training, and guided meditation audio content.Using the Hwa-Byung Diagnostic Interview Schedule, thirty participants aged 19-80 years, diagnosed with HB, will be recruited.After baseline assessments, participants will use the application daily for 4 weeks while continuing their existing stable treatments.The primary outcome is user experience, assessed using a structured questionnaire.Secondary outcomes include changes in HB symptoms, depression, anxiety, anger, psychological flexibility, quality of life, and heart rate variability, measured at multiple time points over 8 weeks.Safety will be monitored through adverse event reporting.In this exploratory study, preliminary data on the feasibility, acceptability, and potential clinical benefits of digitally delivered Korean medicine interventions for HB will be provided. Conclusion:The findings will guide the design of future definitive randomized controlled trials and promote the broader integration of evidence-based digital therapeutics into Korean medicine practice.