Efficacy of Convulsive Therapies for Bipolar Depression

The study will involve a randomized, double blind, non‐inferiority clinical trial with two treatment arms conducted in three academic institutions (the Centre for Addiction and Mental Health (CAMH) in Toronto, Ontario; the Ontario Shores Centre for Mental Health Sciences in Whitby, Ontario; and University of British Columbia (UBC) Hospital in Vancouver, British Columbia). The investigators are pursuing a non‐inferiority clinical trial in an effort to compare MST to right unilateral ultrabrief pulse ECT (RUL‐UB‐ECT). Treatment will be administered two to three days per week. Depression symptoms will be assessed with the 24‐item Hamilton Depression Rating Scale (HRSD‐24) and suicidality will be assessed with the Scale for Suicidal Ideation (SSI). Remission will be defined as HRSD‐24 < or = 10 and a > 60% decrease in scores from baseline on two consecutive ratings. Once a participant reaches remission, a second rating to confirm remission will be conducted immediately before their next scheduled treatment. If remission is confirmed, they will then be considered a completer of the acute treatment course. Remission of suicidal ideation is defined as a score of 0 on the SSI. Therefore, there will be no specific minimum number of treatments that patients must receive to be classified as remitters. However, patients who do not meet remission criteria after 21 treatment sessions will be considered non‐remitters and will cease treatment sessions. This maximum treatment number was chosen allowing for the possibility that MST may require more treatment sessions to achieve remission, similar to RUL‐UB ECT. The blind will not be broken to participants until the completion of the entire study.