This study is about testing a new medicine called azetukalner to see if it helps with Major Depressive Disorder (MDD). MDD is a condition that makes people feel very sad or hopeless for a long time. The study will compare azetukalner to a placebo, which is a harmless pill that doesn’t have any active medicine. This study is called "double-blind," meaning neither the doctors nor the participants will know who gets the real medicine or the placebo. This helps make sure the results are fair.

• The study is for adults aged 18-74 who have had their first major depressive episode before age 50.
• You cannot join if you have other mental health disorders or have used certain medications recently.
• Participants may need to stop taking other antidepressants before joining the study.

It's important to know the study checks how safe and effective the medicine is, but it might involve risks or side effects. Participants will be closely monitored for their safety. If you're interested, consider your current health and talk to a doctor to see if participating is a good choice for you.