Inclusion Criteria:
* Age 18-65
* English proficiency sufficient for informed consent, questionnaires/tasks, and treatment
* Diagnosis of MDD per DSM-5 criteria (Quick Structured Clinical Interview for DSM-5 Disorders) and currently experiencing a moderate to severe episode:
* \>20 on Beck Depression Inventory (BDI)
* \>20 on the Montgomery-Åsberg Depression Rating Scale (MADRS) 14, 15
* Moderate to severe level of treatment resistance (Maudsley Staging Method)16, 17
* Diagnosis of at least one or more of the following psychiatric conditions per DSM-5 criteria (Quick Structured Clinical Interview for DSM-5 Disorders):
* Generalized anxiety disorder (GAD), panic disorder (PD), or social anxiety disorder (SAD)
* Obsessive compulsive disorder (OCD)
* Post-traumatic stress disorder (PTSD)
* Physician referral for individuals with either schizophrenia or schizoaffective disorder
* Stable psychiatric medication regimen, or remain medication free, for 4 weeks prior to treatment and to remain on this regimen throughout the study until the two-week post-treatment visit
* Primary clinician (e.g. psychiatrist, therapist, psychologist, APRN, PA, etc.) responsible for psychiatric care before, during, and after the trial
* Agreement to lifestyle considerations
* Abstain from becoming pregnant from time of screening to two weeks after treatment (post-treatment MRI visit)
* Continue usual intake patterns of caffeine- or xanthine-containing products (e.g. coffee, tea, soft drinks, chocolate) throughout treatment
* Abstain from alcohol, tobacco, and recreational drugs for at least 24 hours before the start of each MRI and each TMS session
Exclusion Criteria:
* Active pregnancy as determined by a urine pregnancy test
* Positive urine drug screen for illicit substances (not including THC)
* Depressive symptoms refractory to 8 sessions of electroconvulsive therapy (ECT)
* Recent (within 4 weeks) or concurrent use of rapid acting antidepressant agent (ketamine/esketamine/ECT)
* Receiving or planning to receive other TMS treatments during course of participation
* History of
* Autism spectrum disorder
* Neurosurgical intervention for depression
* Intellectual disability
* Severe cognitive impairment
* Significant neurological illness (e.g., dementia, Parkinson's, Huntington's, brain tumor, seizure disorder, subdural hematoma, multiple sclerosis, brain lesion)
* Untreated or insufficiently treated endocrine disorder
* Treatment with investigational drug or intervention during the study period
* Depth-adjusted TMS treatment dose \> 65% maximum stimulator output
* Existing tinnitus (ringing in the ears)
* Current evidence of:
* Mania or hypomania
* Active suicidal ideation or a suicide attempt (defined by C-SSRS) within the past year
* Neurological lesion
* Contraindications to either TMS or MRI (e.g., metallic implants, severe insomnia \> 4 hours per night with hypnotic, etc.).
* Moderate or severe substance use disorder or demonstrating signs of acute substance withdrawal (not including cannabis or nicotine use disorders)
* Bipolar I disorder
* For participants with schizophrenia or schizoaffective disorder referred by a physician:
* Total PANSS score \>90
* Score \>4 (moderate-severe) on any positive PANSS item
* Active substance use disorder (other than nicotine)
* Hospitalization for psychosis in the past 6 months
* Severe borderline personality disorder
* Any other condition deemed by the PI to interfere with the study or increase risk to the participant
