Diagnostic Performance and Utility of the Hwabyung Comprehensive Test in Differential Clinical Assessment

Background: Hwabyung is a psychosomatic condition characterized by suppressed anger accompanied by somatic distress. Although traditionally considered a culture-bound syndrome, evidence suggests that Hwabyung reflects culturally shaped manifestations of universal emotional and interoceptive processes. The Hwabyung Comprehensive Test (HCT) was developed to assess Hwabyung symptoms; however, its accuracy for clinical identification and differential discrimination requires further validation in clinically representative samples. Methods: Patients presenting Hwabyung symptoms were recruited from a university hospital and classified using a structured clinical interview as the reference standard. Participants were categorized into a Hwabyung group (HG; n = 100) and a non-Hwabyung group (NHG; n = 82), including a non-Hwabyung clinical group (NHCG; n = 36) and a non-clinical group (NCG; n = 46). The HCT symptom scale, including physical (HCT-P) and emotional (HCT-E) subscales, served as the index test. ROC analyses were conducted to evaluate diagnostic accuracy and optimal cut-off scores. Results: For distinguishing HG from NHG, HCT-total demonstrated good diagnostic accuracy for identifying Hwabyung, with an optimal cut-off score of 33.5 (sensitivity = 0.710, specificity = 0.820). In differentiating HG from NHCG, both HCT-total and HCT-P showed fair discriminative performance, with HCT-P exhibiting higher specificity. A cut-off score of 16.5 for HCT-P yielded a sensitivity of 0.540 and a specificity of 0.833. Conclusions: The HCT demonstrated good diagnostic accuracy for identifying Hwabyung and fair performance in differentiating it from psychiatric disorders. These findings support a stepwise clinical application in which HCT-total is used for initial screening and HCT-P is a supplementary measure for supporting differential diagnostic decision-making.