Inclusion Criteria:  Diagnosis of major depressive disorder OR obsessive-compulsive disorder (DSM-V criteria) Hamilton Depression Rating Scale score greater than or equal to 18 OR Yale-Brown Obsessive-Compulsive Scale score greater than or equal to 16 Failure to respond in the current episode to at least one antidepressant or other pharmacotherapy at an adequate dose and duration as measured by a modified antidepressant treatment history Off antidepressants OR on a stable dose of antidepressants for greater than or equal to four weeks with plans to remain on this stable dose during the study Capacity to consent  Exclusion Criteria:  Imminent risk of suicide (based on the CSSRS) Current depressive episode duration greater than or equal to 2 years Presence of primary psychiatric diagnoses other than OCD, MDD and/or co-morbid GAD (ex. PTSD, MDD with psychotic features, primary psychotic illness, Bipolar I or II) Evidence of cognitive impairment (MMSE score falling 1 SD below mean score for his/her age and education) Evidence of psychotic symptoms on diagnostic interview (interfering with capacity to consent) Have met criteria for any significant substance use disorder within the past 6 months Recent onset (within 8 weeks of screening) of psychotherapy Prior exposure to any form of TMS during the current depressive episode Participated in any clinical trial with an investigational drug or device within the past 6 weeks prior to screening Evidence or history of significant neurological disorder including moderate-severe head trauma, stroke, Parkinson's disease or other movement disorder (except benign essential tremor), epilepsy History of seizures (except juvenile febrile seizures) or any condition/concurrent medication that could notably lower seizure threshold Presence of foreign metal bodies/implanted intracranial devices (MRI contraindication) Current pregnancy or planning to conceive during the study Abnormal bloodwork for electrolytes, thyroid or liver function