This study looks at how well a medicine called Esketamine helps teens with major depressive disorder (MDD) and thoughts of suicide. MDD is a mental health issue where people feel sad and lose interest in activities. Esketamine is given with regular treatment to see if it can quickly help reduce these feelings compared to a fake treatment (placebo) that doesn't have Esketamine.

To join, participants must have been diagnosed with MDD and have high scores on certain depression and suicidality tests. They must also be stable after a physical check-up. However, if they have certain other mental health conditions, allergies to the study drugs, or a history of seizures, they cannot participate.

• The study involves regular visits for evaluations.
• Participants will receive either Esketamine or placebo along with their usual care.
• It's important to consider possible side effects and risks discussed with healthcare providers.