In this project, the investigators evaluate an accelerated schedule of repetitive transcranial magnetic stimulation for treatment-resistant depression. The investigators focuse on participants' brain activity and blood markers (Reelin, Apoer2, NMDAR, BDNF, exosomes and so on) to deepen the understanding of the mechanism of accelerated rTMS for treatment-resistant depression.

In this project, the investigator evaluate an accelerated schedule of repetitive transcranial magnetic stimulation for treatment-resistant depression. Patients were included in two groups and received an accelerated stimulation or sham treatment. The changes of neuroimaging and biomarkers at baseline, 5 days after treatment and 1 month after treatment are evaluated. The investigators focuse on participants' brain activity and blood markers (Reelin, Apoer2, NMDAR, BDNF, exosomes and so on) to deepen the understanding of the mechanism of accelerated rTMS for treatment-resistant depression.

Inclusion Criteria:

1. The current episode met the DSM-5 diagnostic criteria for major depression in patients with first-episode or relapsed unmedicated depression without psychotic symptoms.
2. 24-item Hamilton Depression Scale (HAMD-24) ≥ 20.
3. Age 18-45 years, regardless of gender.
4. Right-handedness.
5. Han Chinese.
6. Signed a written informed consent, willing to participate in the study and be evaluated.

Exclusion Criteria:

1. Co-morbid other mental disorders, including: schizophrenia, mental retardation, substance dependence, etc.
2. Patients with metal objects in the body or with other contraindications to MRI scanning
3. Patients with severe or unstable somatic diseases
4. Women during pregnancy or lactation, and women of childbearing age with positive urine HCG test results during the screening period
5. Other conditions that, in the opinion of the investigator, exist that make participation in this clinical trial inappropriate.