Repetitive Transcranial Magnetic Stimulation (rTMS) using intermittent theta burst stimulation (iTBS) has been found to be a non inferior protocol to standard rTMS for the treatment of major depressive disorder. An accelerated course is of particular interest given the safety profile of the procedure and the potential to treat people more quickly making the treatment more accessible. This study aims to assess the feasibility and clinical outcomes of a high dose iTBS protocol in patients with depression in the context of unipolar or bipolar II disorder who are waiting for Electroconvulsive therapy (ECT) or rTMS due to degree of treatment resistance or severity of symptoms. This is a prospective, open-label, interventional pilot study wherein patients who have been diagnosed with major depressive disorder and referred to brain stimulation clinic, will be recruited for the treatment. Patients will be administered eight questionnaires before and after the treatment to assess the change in clinical outcomes.

Participants will receive same stimulation protocol, however they will be given 6 times per day instead of once per day. Each Treatment will consist of a single iTBS treatment delivering 600 puses of iTBS (bursts of 3 pulses at 50 Hz, bursts repeated at 5 Hz, with a duy cycle of 2 seconds on, 8 seconds off, over 60 cycles and it takes about 3 minutes at a target of 90 to 120% of the subject's resting motor threshold. Treatment will be given through the device that is usually used, which is Magpro by Magventure, B70 Fluid-Cooled Coil .

Inclusion Criteria:

• 18 years and older
• Unipolar Depression or Bipolar II depression based on the MINI - no psychotic features
• Pass the TMS safety screen on the brain stimulation consultation template Voluntary and Competent to consent to treatment

Exclusion Criteria:

• Have a MINI confirmed diagnosis of a substance use disorder within the last month
• Have a concomitant major unstable medical illness, cardiac pacemaker or implanted mediation pump
• Have a lifetime MINI diagnosis of bipolar I, or schizophrenia, schizoaffective disorder, schizophreniform disorder, delusional disorder.
• Have any significant neurological disorder or insult including but not limited to: any condition likely to be associated with increased intracranial pressure, space occupying brain lesion, any history of seizure except those therapeutically induced by ECT, or a febrile seizure of infancy or single seizure related to a known drug related event, cerebral aneurysm, or significant head trauma with loss of consciousness for greater than 5 minutes
• Have an intracranial implant (e.g. aneurysm clips, shunts, stimulators, cochlear implants, or electrodes) or any other metal object within or near the head (excluding the mouth) that cannot be safely removed.
• Currently taking more than lorazepam 2mg daily (or equivalent) or any dose of an anticonvulsant due to the potential to limit rTMS efficacy.