Zuranolone Pharmacokinetics (PK) and Safety Study Adolescent Participants With Major Depressive Disorder (MDD)

Inclusion Criteria: * Participant meets Kiddie Schedule for Affective Disorders and Schizophrenia - Present and Lifetime DSM-5 (KSADS-PL DSM-5) criteria for MDD. * Participant has a Children's Depression Rating Scale-Revised (CDRS-R) total score greater than or equal to 40 at screening and Day 1. * Participant's parent/caregiver is able to attend all scheduled study visits, oversee administration of study drug and complete assessments per the protocol. * Participant has a body weight greater than or equal to 20 kg and a body mass index greater than fifth percentile and less than ninety-fifth percentile for age at Screening. * Participant is a post-pubertal (has experienced menarche) female (sex assigned at birth), 12 to 17 years of age, inclusive, at the time informed consent/assent is obtained. Exclusion Criteria: * Participant has a history of psychosis, bipolar disorder, autism, seizures, or other restricted comorbid psychiatric or neurological conditions and has treatment-resistant depression. * Participant has a known diagnosis of intellectual disability or is unable to communicate with the study investigator or research team. * Participant has a history of suicidal behavior or is currently at risk of suicide in the opinion of the investigator. * Participant has a recent history of Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM 5) alcohol or drug use disorder or has clinically significant alcohol or drug misuse as judged by the investigator. Note: Other protocol-defined inclusion/exclusion criteria may apply.