This artical starts from the perspective of "earth stagnation and wood depression" to analyze the dynamic mutual impairment process between breast cancer and mixed anxiety and depressive disorder (MADD), integrating pathological evidence of mutual causality between physical impairment and internal injury by emotional distress, to provide a theoretical framework elucidating the intrinsic unity of the microbiota-neuro-tumor interaction network in the comorbidity vicious cycle. The comorbidity of breast cancer and MADD manifests dynamic mutually aggravating impairment, with core pathogenesis according to the traditional Chinese medicine theory of "earth stagnation and wood depression": spleen earth stagnation leads to dampness-turbidity obstruction, while dysfunction of the middle jiao pivot result in abnormal liver qi conveyance and dispersion; liver depression transforming into fire further over-restricts on spleen earth. Mutual over-restriction and counter-restriction between the two causes toxic fire, phlegm and blood stasis to conglomerate into masses. The lingering disease progression causes mutual damage between body and spirit, leading to progressive consumption until physical collapse and spiritual decline, ultimately culminating in earth exhaustion and wood withering, toxins infiltrating the extraordinary vessels, and divorce of yin-yang. Gut microbiota dysbiosis induces abnormalities in the metabolic-immune-neuroendocrine network, driving emotional disorders and interacting with the tumor microenvironment to exacerbate deterioration. This mechanism not only validates the concept of "earth stagnation and wood depression-mutual physical-mental impairment", but also elucidates its role in inducing multi-system cascade failure, ultimately culminating in a pathological process marked by the emergence of severe clinical manifestations.