This study tests a new medicine called NMRA-335140 for people with Major Depressive Disorder (MDD). MDD is a condition where people feel very sad for a long time and it affects their daily life. The study lasts 6 weeks, and during this time, participants will take either the medicine or a placebo (a pill with no medicine). A placebo helps researchers see if the medicine really works. The study is "double-blind," which means neither the participants nor the doctors know who gets the real medicine and who gets the placebo. To join, participants must have had MDD symptoms for more than 4 weeks but less than a year. They shouldn't have certain other conditions like bipolar disorder or severe substance use. People who are actively thinking about harming themselves or others can't join. After the study, those who finish may join an additional study where everyone gets the real medicine.
- The study lasts for 6 weeks with possible extension.
- Participants take either NMRA-335140 or a placebo.
- Certain mental health conditions disqualify participation.