NQ Square TMS for MDD 1Dx3S Adults Multi-site Sham-controlled Protocol

Inclusion Criteria: 1. Males or females aged 22-85. 2. Current diagnosis of major depressive disorder according to the criteria defined in the current Diagnosis and Statistical Manual of Mental Disorders (DSM-V) without psychotic features. The diagnosis of DSM-5 criteria-defined MDD will be made by a psychiatrist in light of a comprehensive psychiatric evaluation and other available clinical data. 3. Drug-resistant MDD (lack of improvement on antidepressant medication in the current episode, despite adequate dose and duration and adherence to treatment). 4. MADRS score \> 20 at baseline and immediately prior to the day of treatment. 5. Agrees to adhere to the study treatment and follow-up schedule. 6. Evidence of no change in AD medications or psychotherapy from 4 weeks prior to enrollment and participant's agreement not to request such changes through 2 weeks after study regimen treatment. 7. Fluent in English. Exclusion Criteria: 1. Any medical conditions that would preclude the use of rTMS to treat depression. 2. Any conditions that would prevent the ability to undergo MRI testing. 3. Pregnancy as determined by serum/urine pregnancy test 4. History of epilepsy, seizure(s), or a seizure disorder as determined by the principal investigator based on a medical history obtained from the patient and/or others authorized to provide such history, combined with a brief screening instrument. 5. Active substance abuse 6. Diagnosis of bipolar or psychotic disorder 7. Considered to be at moderate-high risk of suicide according to the C-SSRS assessment (i.e., Answers YES to Question 3 and NO to Question 6; or answers YES to Question 4, 5, or 6) 8. As determined by the Principal Investigator, subjects with cognitive impairment according to either the medical history obtained from the patient and/or a reliable secondary source, or the results of the Montreal Cognitive Assessment (MoCA) performed during screening.