i-CBT and IV Ketamine for Suicidality in Treatment-Resistant Depression: A Randomized, Midazolam-Controlled Clinical Trial

Approximately four thousand Canadians die by suicide every year, and suicide is the second leading cause of death in youth and young adults (15-34 years). Most people with depression experience thoughts of suicide and many will also plan and/or attempt suicide at some time in their life. There is an urgent need for new scalable treatments that can effectively reduce suicidality in people with depression. Cognitive behavioural therapy (CBT) reduces suicidal thoughts and behaviours, and can be delivered through the internet (i-CBT) making it more accessible and scalable. However, i-CBT has not been shown to rapidly reduce suicidal thoughts and behaviours (suicidality), such as within 24 hours. IV ketamine on the other hand has been shown to rapidly reduce thoughts of suicide, but not suicidal behaviours. Therefore, combining i-CBT with IV ketamine may be more effective reducing suicidality than i-CBT treatment with a control treatment. The investigators propose a 13-week, multi-site, study that looks at how combining i-CBT and IV ketamine treatment will affect suicidality in individuals with depression who have recently experienced suicidal thoughts and/or behaviours, but have not responded to previous treatment. All 110 participants will receive a weekly session of i-CBT for 13 weeks, but half will be randomly assigned to also receive six IV ketamine treatments or six IV midazolam treatments (control treatment) over the first initial 30 days. The investigators will measure changes in suicidal thoughts and behaviours before drug treatment and at the primary endpoint (i.e.,day 30), and after 3 months (i.e. Day 91) of the starting treatment.