A Short-term Exploratory Study to Evaluate Safety, Tolerability and Pharmacokinetics of Seltorexant as Adjunctive Therapy to Antidepressants in Adolescents With Major Depressive Disorder Who Have an Inadequate Response to SSRI Monotherapy and Psychotherapy

Seltorexant

Placebo

Number of Participants with Treatment Emergent Adverse Events (TEAEs)

Number of Participants with Adverse Event of Special Interest (AESIs)

Pediatric Adverse Event Rating Scale (PAERS)

Number of Participants with Abnormalities in Clinical Laboratory Values

Number of Participants with Abnormalities in Electrocardiogram (ECG)

Number of Participants with Abnormalities in Vital Signs

Number of Participants with Abnormalities in Physical Examination

Suicidality Assessment Using the Columbia Suicide Severity Rating Scale (C-SSRS) Score

Withdrawal Symptoms Assessment Using the Physician Withdrawal Checklist (PWC-20)

Number of Participants with Menstrual Cycle Tracking

Change from Baseline to Week 6/End of Treatment (EOT) in the Children's Depression Rating Scale (CDRS) Total Score

Change from Baseline to Week 6 in Montgomery Asberg Depression Rating Scale (MADRS) Score

Change from Baseline in Clinical Global Impression- severity (CGI-S) Score Over Time

Change from Baseline to Week 6/EOT on Subjective Sleep Assessment (Patient Reported Outcome Measurement Information System-Pediatric-Sleep Disturbance [PROMIS-Pediatric-SD] [Short Form 8a])

Change from Baseline to Week 6/EOT on Objective Sleep Assessment Actigraphy

Cognitive Performance on a Neurocognitive Battery at Baseline and Week 6/EOT

Plasma Concentration of Seltorexant