Biopsychological pattern underlying the psychosomatic symptoms of patients with Hwabyung from a universal perspective

Background: Hwabyung is a psychiatric syndrome originally described in Korea that presents as chronic psychosomatic distress with emotional dysregulation and heightened somatic arousal. However, no objective analysis to clarify its progressive mechanism within a universal biopsychological framework has as yet been done that incorporates insights from traditional East Asian medical psychology. Methods: We recruited 118 patients with Hwabyung and assessed their psychological and somatic symptoms using the Hwabyung Test (HB). Levels of depression, anxiety, and anger expression, as well as biopsychological features were evaluated with the Sasang Personality Questionnaire (SPQ). Psychological and somatic symptoms of Hwabyung were predicted through a regression analysis that used three SPQ subscales: behavioral activation (SPQ-B), cognitive flexibility (SPQ-C), and emotional responsiveness (SPQ-E). Hwabyung subgroups were identified by K-means analysis and their psychosomatic and biopsychological patterns were analyzed with HB and SPQ through ANCOVA and Profile Analysis to explore underlying biopsychological dimensions beyond culture-specific frameworks. Results: The SPQ subscales explained 26.0% of the psychological and 14.3% of the somatic symptoms of Hwabyung. Three distinct Hwabyung subgroups (mild, moderate, and severe) were identified based on the severity of psychological and somatic symptoms. Patients with severe symptoms showed a unique SPQ subscale profile with high SPQ-B, low SPQ-C, and low SPQ-E scores, reflecting volatile, aggressive, rigid, pessimistic, repressed, and isolated biopsychological characteristics. Discussion: This study suggests a representative SPQ subscale profile of Hwabyung and underlying mind-body interaction mechanisms within East-Asian biopsychological theory. It offers a more comprehensive and generalizable understanding of Hwabyung and other culture-bound psychosomatic syndromes, supporting improved diagnostic and intervention strategies across populations.