Eligibility Criteria:
Inclusion Criteria:
* Diagnosis of unipolar major depressive disorder, in a current major depressive episode, without psychotic features
* Pretreatment CDRS-R Raw score ≥ 40
* Age is at least 13 and less than 19 years
* Ongoing, stable dose antidepressant therapy for at least 6 weeks to include the following antidepressants (with dosing range):
* Celexa (citalopram hydrobromide) - 10 to 60mg
* Cymbalta (duloxetine) - 40mg to 120mg
* Desyrel (trazodone HCl) - 12.5mg to 150mg
* Effexor (venlafaxine HCl) - 37.5mg to 300mg
* Luvox (fluvoxamine maleate) - 25mg to 200mg
* Lexapro (escitalopram oxalate) - 10mg to 40mg
* Paxil (paroxetine HCl) - 10mg to 50mg
* Pristiq (desvenlafaxine) - 50mg to 100mg
* Prozac (fluoxetine HCl) - 10mg to 80mg
* Remeron (mirtazapine) - 7.5mg to 45mg
* Zoloft (sertraline HCl) - 25mg to 200mg
* Subjects able to attend at least 31 study visits at Mayo Clinic - Rochester
* Willing to provide informed assent (adolescent) and informed consent (family)
Exclusion Criteria:
* Subjects currently on stimulant, antipsychotic, bupropion or tricyclic antidepressant medications.
* Prior rTMS, vagus nerve stimulation (VNS) or electroconvulsive therapy (ECT)
* Contraindication to MRI
* Contraindication to rTMS (history of neurological disorder such as seizures, increased intracranial pressure, brain surgery, or head trauma with loss of consciousness for \>15 minutes, history of stroke, family history of epilepsy, intracardiac lines, Anticoagulant, immune suppressive and/or chemotherapy, or those who received any of these therapies within 3 months before enrollment in the study Unstable medication conditions such as hematological or infectious (e.g., human immunodeficiency virus-HIV) disorders, implanted electronic device, metal in the head, or pregnancy)
* History of schizophrenia, schizoaffective disorder, other \[non mood disorder\] psychosis, depression secondary to a medical condition, mental retardation, substance dependence or abuse within the past year (except nicotine), bipolar disorder, psychotic features in this or previous episodes, amnestic disorder, obsessive compulsive disorder, post-traumatic stress disorder, panic disorder
* History of autoimmune, endocrine, viral, or vascular disorder.
* Unstable cardiac disease, uncontrolled hypertension, or sleep apnea
* Active suicidal intent or plan, or history of attempt within the past 6 months