['depressive disorder, major']
['rapastinel', 'placebo']

        Inclusion Criteria:

          -  Meet Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)
             criteria for MDD

          -  Current major depressive episode of at least 8 weeks and not exceeding 18 months in
             duration at Visit 1

          -  Have no more than partial response (< 50% improvement) to ongoing treatment with a
             protocol-allowed antidepressant

          -  If female of childbearing potential, have a negative serum β-human chorionic
             gonadotropin (β-hCG) pregnancy test.

        Exclusion Criteria:

          -  DSM-5-based diagnosis of any disorder other than MDD that was the primary focus of
             treatment within 6 months before Visit 1

          -  Lifetime history of meeting DSM-5 criteria for:

               1. Schizophrenia spectrum or other psychotic disorder

               2. Bipolar or related disorder

               3. Major neurocognitive disorder

               4. Neurodevelopmental disorder of greater than mild severity or of a severity that
                  impacts the participant's ability to consent, follow study directions, or
                  otherwise safely participate in the study

               5. Dissociative disorder

               6. Posttraumatic stress disorder

               7. MDD with psychotic features

          -  Significant suicide risk, as judged by the Investigator.
      