Clinical Research Directory

Inclusion Criteria: 1. Age 18-65 years old, regardless of gender; 2. The subject is an outpatient/inpatient and meets DSM-5 diagnostic criteria of current or past major depressive disorder; 3. SSRIs or SNRIs monotherapy; 4. HAMD-17 total score ≥ 18 at baseline; 5. The subject can read and write and is capable of giving informed consent. Exclusion Criteria: 1. Patients with mental illness other than MDD; 2. Patients with liver and kidney diseases, cardiovascular system diseases, cancer, diabetes, thyroid diseases or other serious or unstable conditions; 3. Previous organic brain disease, traumatic brain injury or other diseases that can cause structural brain changes; 4. Serious abnormalities indicated by laboratory tests or electrocardiograms; 5. Alcohol or drug addiction; 6. Suffering from systemic lupus erythematosus, multiple sclerosis or other autoimmune diseases; 7. Patients who are taking drugs that directly impact on the immune system such as anti-inflammatory drugs or immunosuppressants; 8. Patients who have taken antidepressants or other antipsychotics within 2 weeks before enrollment; 9. Patients who have received MECT or systematic psychotherapy within 3 months before enrollment; 10. Patients at high risk of suicide, or reporting a HAMD-17 item 3 (suicide item) score \>3 at baseline; 11. Subjects who are pregnant or lactating; 12. Other conditions that are considered not suitable for participating in the research.