Theta Burst Stimulation for Refractory Depression in Autism Spectrum Disorder

Inclusion Criteria: 1. Fluent in English and able to volunteer in the informed consent process and provide spontaneous narrative description of key elements, risks, and benefits of the study. 2. Aged 13-26, inclusive. 3. Full-scale intelligence quotient ≥ 70. 4. Diagnosis of ASD using criteria from Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5). Diagnosis will be confirmed by study psychologist/social worker and supported by scoring in the ASD on the Autism Diagnostic Observation Schedule (ADOS-2). 5. Diagnosis of MDD based on psychologist diagnosis and DSM-5-based structural diagnostic interview determine via KSADS 6. Exhibiting treatment resistance to at least one antidepressant drug treatment of adequate dose and duration. 7. Symptoms of moderate to severe depression according to Hamilton Depression Rating Scale ≥ 20 which must be maintained through lead-in period. 8. Participants are not required to discontinue current interventions but must agree to attempt to keep medications and other interventions stable during the study. Exclusion Criteria: 1. Participation in an investigational drug trial within the past three months. 2. Active substance use disorder (excluding tobacco use) within the past 6 months. 3. Contraindications to Transcranial Magnetic Stimulation including, but not limited to, a history of epilepsy, the presence of metallic foreign bodies, or implanted medical devices (e.g. pacemaker, medical pump). 4. Actively suicidal (i.e., suicidal ideation with plan and intent) or deemed at high risk for suicide. 5. Current use of anticonvulsant, barbiturate, lithium, or benzodiazepine medications. 6. Prior rTMS treatment. 7. For female subjects of childbearing potential, a positive urine pregnancy test.