A Study to Investigate Evoked Potentials as Markers of Ketamine-induced Cortical Plasticity in Patients With Major Depressive Disorder

This study will be conducted in patients with Major Depressive Disorder (MDD) and divided into 2 sequential cohorts. Cohort 1 will be conducted in 12 patients at a single center. For each patient, there will be up to 4 sequential phases: a screening phase of up to 6 weeks, an open-label treatment phase of up to 4 weeks, an optional open-label treatment phase of up to 1 week, and a follow-up phase of up to 1 week (if applicable). Cohort 2 will be conducted in 20 patients and will be a multicenter, double-blind (neither physician nor patient knows the treatment that the patient receives), randomized (the study drug is assigned by chance), placebo-controlled (an inactive substance that is compared with a drug to test whether the drug has a real effect in a clinical trial) design. For each patient, there will be up to 4 sequential phases: a screening phase of up to 6 weeks, a double-blind treatment phase of up to 4 weeks, an optional open-label treatment phase of up to 1 week, and a follow-up phase of up to 1 week (if applicable). The total study duration for each patient will be maximally about 12 weeks. Participant safety will be monitored throughout the study.