This study looks at how well a medication called AXS-05 works compared to bupropion in stopping depression from coming back in people with major depressive disorder (MDD). MDD is a condition where people feel very sad for a long time. The study has two parts. First, everyone gets AXS-05 for 10 weeks to see how it helps. If it works, they move to the next part where they either keep taking AXS-05 or switch to bupropion to see which one works better to prevent depression from returning. This second part lasts for about 26 weeks.

• Study lasts up to 36 weeks (10 weeks open-label, 26 weeks double-blind).
• Participants must have MDD and no other mental health conditions.
• You can't join if you've taken part in a similar study or used certain medications recently.