Positioning of Esketamine Treatment in the Real-world Management of Depression

This is an uncontrolled, single arm, naturalistic study. There will be three treatment phases: Phase 1 - Acute treatment phase (weeks 1-4); Phase 2 - Maintenance treatment phase (weeks 5-8); Phase 3 - Continuation treatment phase (Weeks 9-25). Phase 1 is the critical component of our study as it determines our primary outcomes.