Focused Research On Neurofeedback Therapy In Eradicating Depression (FRONTIER)

Inclusion Criteria: * 1\. Adults (at least 18 years old at the time consent is obtained) * 2\. Major depressive episode as defined by the diagnostic criteria of the DSM 5 * 3\. One of the following 1. Hamilton Depression Rating Score (HDRS 17) of 19 or higher 2. Montgomery Asberg Depression Rating Scale score of 20 or higher 3. Any other patient deemed appropriate by the PI (subprincipal investigator) * 4\. With respect to taking antidepressants, any of the following 1. not taking antidepressants 2. If taking antidepressants, willingness to continue them for the duration of the program. * 5\. If receiving psychotherapy, agree to continue the same psychotherapy for the duration of study participation * 6\. Have treated by a psychiatrist * 7\. Written informed consent * 8\. No planned change in employment status after the study begins Exclusion Criteria: * 1\. High risk of suicide, such as suicidal ideation or suicide attempts * 2\. History of hospitalization for depression or suicidal behavior * 3\. Comorbid addictions (drugs, alcohol) or history of addictions * 4\. Organic brain disease (e.g., moderate or severe intracranial organic lesions or neurodegenerative disease) * 5\. History of seizures or epilepsy * 6\. Has a serious or unstable physical disease * 7\. Difficulty or inappropriateness/contraindication to MRI imaging * 8\. Pregnant women or unwilling to practice contraception during the study * 9\. Participating in another clinical trial at the same time, or have participated in a clinical trial within the past 90 days, or are scheduled to participate in another clinical trial during the study period, and the principal (sub)investigator determines that participation in another clinical trial may interfere with the results of this study * 10\. Other cases in which the principal investigator (or subinvestigator) determines that it is difficult to conduct this study safely.