Exploring the Pathogenetic Characteristics and Therapeutic Strategies of Yu Syndrome Based on the Theory that “The Liver is Yin in Substance and Yang in Function”

Abstract

Yu syndrome (depressive disorder) is a common clinical condition characterized by emotional disturbance, the pathogenesis of which is closely associated with dysregulation of emotions and impaired hepatic dispersion and coursing. With changes in modern lifestyles and increasing psychosocial stressors, the incidence of Yu syndrome has risen steadily. Clinically, its pathogenesis is often complex, prone to chronicity, and liable to recurrence. Current understanding predominantly attributes the disorder to liver qi stagnation; however, treatment strategies focused solely on soothing the liver and relieving stagnation have shown inconsistent efficacy in some patients, suggesting that deeper pathomechanisms warrant further exploration. In traditional Chinese medicine (TCM), the liver governs dispersion and regulates emotional activities. The theory that “the liver is yin in substance and yang in function” elucidates the intrinsic relationship between body (ti) and function (yong) of the zang-fu organs, proposing that the liver is rooted in yin-blood as its substance while manifesting dispersion and ascending movement as its functional aspect. This theoretical framework provides a critical perspective for refining the understanding of emotional disorders associated with the liver system. Based on a systematic review of the theoretical connotations of “the liver is yin in substance and yang in function,” and in consideration of the etiological and pathodynamic characteristics of Yu syndrome, this paper reexamines the onset, progression, and transformation of Yu syndrome from the perspective of imbalance between liver substance and liver function. Furthermore, it explores corresponding principles of pattern differentiation and therapeutic strategies. The aim is to enrich the theoretical understanding of the pathogenesis of Yu syndrome and to optimize clinical treatment approaches.