Xiaochaihu Granules for Depression After Allogeneic Hematopoietic Stem Cell Transplantation

Inclusion Criteria: * Participants must meet all of the following criteria: 1. Able to understand the study procedures and voluntarily provide written informed consent (or consent from a legal guardian where applicable); 2. Age ≥14 years, male or female; 3. Patients who have undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT); 4. Newly diagnosed depression after allo-HSCT, assessed by standardized scales (e.g., HADS and/or HAMD); 5. Evidence of successful neutrophil engraftment prior to enrollment; 6. Willing and able to comply with study procedures and follow-up assessments. Exclusion Criteria: 1. Refusal to participate in the study; 2. Presence of severe psychiatric disorders or severe somatic symptom disorders; 3. Known allergy to Xiaochaihu Granules or any of its components; 4. Current use of other antidepressant medications; 5. Severe organ dysfunction or unstable clinical condition, including but not limited to: Uncontrolled bloodstream infection; Expected survival \<3 months; 6. History of splenectomy; 7. Renal insufficiency with serum creatinine ≥2.0 mg/dL; 8. Cholestatic liver disease or unresolved hepatic veno-occlusive disease (VOD); 9. Significant cardiovascular conditions, including: Unstable angina; Acute myocardial infarction within 6 months prior to enrollment; NYHA class III-IV heart failure; Circulatory failure requiring vasoactive or inotropic support; Clinically significant arrhythmia requiring treatment; 10. Severe respiratory disease requiring mechanical ventilation or ≥50% oxygen support; 11. Patients whose primary disease is in complete remission after transplantation (per protocol definition); 12. Participation in another interventional clinical trial within 21 days prior to enrollment (or within 5 half-lives of the investigational product, whichever is longer); 13. Any other condition deemed by the investigator to make the patient unsuitable for participation.