Table 1 Inclusion and exclusion criteria

Inclusion criteria:

  1. Aged 18 to 65 years

  2. Right-handed

  3. Diagnosed with MDD based on DSM-5 criteria by at least one qualified psychiatrist

  4. 24-item Hamilton Rating Scale for Depression (HAMD-24) score ≥ 17

  5. Completed ECT treatment

  6. Capable of comprehending and completing the study assessments

  7. Written informed consent provided by patients and/or their legal guardians

Exclusion criteria:

  1. Severe systemic illnesses (e.g., hepatic, renal, respiratory, cardiovascular, endocrine, hematological, oncological diseases)

  2. Diagnosis of schizophrenia, bipolar disorder, dementia, substance dependence or abuse, or any primary psychotic disorder according to DSM-V criteria

  3. Skin lesions or dermatological issues at electrode sites

  4. Metal implants or electrically sensitive devices

  5. Neurological conditions (e.g., stroke, seizure disorders) affecting cognition or treatment response

  6. ECT within the past six months

  7. Known hypersensitivity or contraindication to concurrent ECT medications

  8. Pregnant or lactating

  9. Receiving transcranial magnetic stimulation or other neuromodulation treatments

  10. Participation in another concurrent clinical trial