Transcranial Direct Current Stimulation for Depression

Inclusion Criteria: 1. Participants who meet the criteria of major depression defined by DSM-5 criteria 2. Participants will be non-responders and taking an antidepressant of adequate dose and for ≥4 weeks in the current episode which has not led to sufficient clinical improvement (defined as a minimum level of 2 on the ATHF); or can't tolerate the adverse effects of antidepressant in the current episode 3. Ambulatory participants with or without any aiding device Exclusion Criteria: 1. An urgent risk of suicide or severe depression 2. A history of ineffectiveness with tDCS 3. People who are clinically contraindicated to receive tDCS intervention or MRI assessment, such as having any brain lesion, intracranial implants (clips, cochlear implants), a tattoo or metal embedded in their scalp or brain 4. Any instable medical condition 5. A history of epilepsy, 6. A history of substance use (within one year) 7. People with dementia or psychotic disorder. 8. Any condition which would make the subject unsuitable for the study under the physician's assessment.