Inclusion Criteria:

• Inpatients or outpatients.
• Voluntary clinical patient with the capacity to assent (or consent if 18) to treatment and a parent or legal  guardian with the capacity to consent (if younger than 18).
• Biological female or male (nonbinary or other gender identities are not exclusionary).
• 12-18 years of age.
• Diagnosed with MDD based on Diagnostic and Statistical Manual for Mental Disorders, 5th edition (DSM-5) criteria with the Mini-International Neuropsychiatric Interview for Children and Adolescents (MINI Kid) in subjects 12-17 years of age; The Mini-International Neuropsychiatric Interview will be used for subjects who are 18 years of age.
• In a current episode of MDD with duration of at least 4 weeks but less than 3 years.
• Depressive symptom severity as demonstrated by CDRS-R total composite score of forty or greater and a suicidal ideation score of 3 or more on item 13 of the CDRS-R.
• A minimum score of 1 (“wish to be dead”) on the C-SSRS severity of ideation subscale.
• Demonstrating that depressive symptom severity as evaluated at the screening visit does not improve between screening and baseline by 25% or more.
• Eligible for transcranial magnetic stimulation (TMS) based on safety criteria.
• On a medically acceptable form of birth control during the 10 day acute treatment course if female and of child bearing potential.
• Taking an antidepressant medication if recommended by the referring clinician and agreed upon by parents and patients. Please note that patients are not required to take an antidepressant medication for study participation for practical, ethical, and human subject protection concerns. Medication status and prior treatment resistance will be carefully recorded with the Antidepressant Treatment History Form criteria for relevant statistical considerations.

Exclusion Criteria:

• Diagnosis of a psychotic disorder, bipolar disorder, anorexia nervosa, bulimia nervosa, substance use disorders within the past year (with the exception of caffeine and tobacco).
• Lifetime diagnosis of a psychotic disorder confirmed by a research screening interview (including schizophrenia, major depressive disorder with psychotic features, and bipolar disorder with psychotic features).
• Intelligent quotient less than 70 (if there is a clinical concern, subjects will be psychometrically assessed with the Slosson Intelligence Test, Revised).
• Positive urine drug screen at baseline.
• Patients with a history of epilepsy or unexplained seizures.
• Any family history of epilepsy.
• Patients medicated with drugs lowering the seizure threshold (examples: neuroleptic agents and tricyclic antidepressants).
• History of any treatment with electroconvulsive therapy or TMS.
• Use of any investigational drug within 4 weeks of baseline.
• Prior brain surgery.
• Risk for increased intracranial pressure such as a brain tumor.
• Life-time history of head trauma with loss of consciousness for greater than 5 minutes duration.
• Any true positive findings on the TMS safety screening form (TASS).
• Pregnant or nursing patients.
• Conductive, ferromagnetic, or other magnetic-sensitive metals implanted in the head within. 30 cm of the treatment coil excluding the mouth that cannot be safely removed (examples include cochlear implants, vagus nerve stimulators, deep brain stimulators, implanted electrodes/stimulators, aneurysm clips or coils, stents, bullet fragments, jewelry and hair barrettes).
• Patients with any implanted stimulators or implants controlled by physiologic signals, including VNS, SCS, PNS, defibrillators and pacemakers.
• Patients with neurological conditions that include a history of seizures, cerebrovascular disease, cerebral aneurysm, dementia, movement disorders, having a history of repetitive or severe head trauma, or with primary or secondary tumors in the CNS.
• Patients with a history of increased intracranial pressure, history of severe headaches within the previous 1 year, or severe head trauma.
• Implanted medication pumps and cardiac pacemakers.
• Patients suffering from vascular, traumatic, tumoral, infectious, or metabolic lesions of the brain, even without a history of seizure, or without anticonvulsant medication.
• Patients with an unstable medical illness (other than depression).
• Inability to adhere to the protocol.

Eligibility last updated 1/20/22. Questions regarding updates should be directed to the study team contact.