NBI-1065845-MDD3025: Study to Assess the Efficacy and Safety of NBI-1065845 as an Adjunctive Treatment in Participants With Major Depressive Disorder (MDD)

This study is testing a new experimental medication called NBI-1065845 as an add-on treatment for people with major depressive disorder (MDD) who have not responded well enough to their current antidepressants. **You may be eligible if...** - You have been diagnosed with recurrent major depression (moderate or severe) or persistent depressive disorder - Your current antidepressant has not been working well enough in this episode - You have been taking an oral antidepressant for at least 8 weeks and are willing to continue it during the study - Your depression scores on a standard rating scale are still significantly elevated **You may NOT be eligible if...** - You have another psychiatric disorder that was the main focus of treatment in the past year (other than depression) - You are considered at risk of harming yourself or others - Your depression has previously not responded to electroconvulsive therapy (ECT) in this episode Talk to your doctor to see if this trial is right for you.