Efficacy of Convulsive Therapies for Bipolar Depression

Inclusion Criteria: Patients will be included if they: 1. are inpatients or outpatients; 2. are voluntary and competent to consent to treatment and research procedures according to ECT/MST attending psychiatrist; 3. have a MINI International Neuropsychiatric Interview diagnosis, Version 6 (MINI-6.0) diagnosis of non-psychotic Bipolar Disorder (Type I or II) 4. are 18 years of age or older 5. have a baseline HRSD-24 score \> 21; 6. are considered to be appropriate to receive convulsive therapy as assessed by an ECT attending psychiatrist and a consultant anaesthesiologist 7. are agreeable to keeping their current antidepressant treatment constant during the intervention; 8. are likely able to adhere to the intervention schedule; 9. meet the MST safety criteria; 10. If a woman of child-bearing potential: is willing to provide a negative pregnancy test and agrees not to become pregnant during trial participation. Exclusion Criteria: Patients will be excluded if they: 1. have a history of MINI diagnosis of substance dependence or abuse within the past three months; 2. have a concomitant major unstable medical illness; 3. are pregnant or intend to get pregnant during the study; 4. have a MINI diagnosis of any primary psychotic disorder 5. have a MINI diagnosis of obsessive compulsive disorder, or post-traumatic stress disorder deemed to be primary and causing more functional impairment than the depressive disorder 6. have probable dementia based on study investigator assessment; 7. have any significant neurological disorder or condition likely to be associated with increased intracranial pressure or a space occupying brain lesion, e.g., cerebral aneurysm; 8. present with a medical condition, a medication, or a laboratory abnormality that could cause a major depressive episode or significant cognitive impairment in the opinion of the investigator (e.g., hypothyroidism with low TSH, rheumatoid arthritis requiring high dose prednisone, or Cushing's disease); 9. 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; 10. require a benzodiazepine with a dose greater than lorazepam 2 mg/day (or equivalent benzodiazepine) or any anticonvulsant due to the potential of these medications to limit the efficacy of both MST and ECT; 11. are unable to communicate in English fluently enough to complete the neuropsychological tests; 12. have a non-correctable clinically significant sensory impairment (i.e., cannot hear or see well enough to complete the neuropsychological tests). These eligibility criteria are congruent with the criteria that have been used in the major ECT trials conducted during the past decade; 13. elevated mood, defined as a score of 20 or higher on the Young Mania Rating Scale (YMRS).