Inclusion Criteria:

• Ages 12-18
• Primary diagnosis of major depressive disorder based on a structured diagnostic interview with the Mini International Neuropsychiatric Interview (M.I.N.I.)
• Score of 40 or greater on the Children’s Depression Rating Scale-Revised (CDRS-R)
• Participants must have the ability to commit to the study schedule for rTMS treatments.
• Healthy control participants will be between ages 12-18
• Healthy control participants will have no psychiatric diagnoses or unstable medical conditions (based on M.I.N.I and clinical interview)

Exclusion Criteria: 

• Currently taking antidepressant medication.
  • For potential depressed participants on antidepressant medication, the referring clinician must determine that insufficient benefit has been received from the treatment and it is clinically appropriate to discontinue the existing antidepressant prior to enrollment in the study. 
• Currently in psychotherapy
  • Stable treatment for 3 months prior to screening into the study with no anticipated change in the frequency or therapeutic focus of the sessions for the duration of study participation.   
• Pregnancy
• Individuals diagnosed (based on M.I.N.I) with psychotic disorders, bipolar disorder, anorexia nervosa, bulimia nervosa
• History of neurological disorder or insult that might increase risk of seizure
• Contraindications to MRI/MRS or rTMS based on systematic safety screens such as implanted metal
• Prior brain surgery, risk for increased intracranial pressure such as a brain tumor
• Unstable medical condition based on principal investigator discretion.
• Active substance use within the past month (participants with a positive urine drug screen at baseline are excluded). 
• Substance use disorders within the past year (with exception of caffeine or tobacco)