Pragmatic, randomised, controlled, parallel-group, superiority trial. Trial participants will be patients admitted to St Patrick's University Hospital for treatment of a major depressive episode. The investigators aim to recruit up to 104 participants who will be eligible for this study and randomly allocate 52 patients to each group. Both participants and assessors will be blind to treatment allocation. Eligible consented participants will be randomly allocated in a 1:1 ratio to a course of up to eight infusions of either ketamine or midazolam twice weekly over up to four weeks. Block randomisation will be independently performed. Physical, psychotomimetic and cognitive outcomes will be monitored before, during and after infusions. During the allocated infusions and follow-up period patients will be monitored for treatment-related adverse events relating to both mental and physical health. Participants will also be followed-up for 24 weeks after the end of the initial randomised treatment and assessment period lasting up to four weeks, in order to identify if and when relapse occurs. During the trial, both groups will continue usual inpatient care as prescribed by their treating team.
Pragmatic, randomised, controlled, parallel-group, superiority trial of ketamine vs. midazolam as an adjunctive therapy for depression. The main purpose of the trial is to assess the mood-rating score difference between ketamine and midazolam from before the first infusion to 24 hours after the final infusion, supplemented by a 95% confidence interval. There will also be a 24-week follow-up after the final infusion session.