This study looks at how safe and tolerable a new medicine, NBI-1065845, is for people with Major Depressive Disorder (MDD). MDD is a condition where people feel very sad for a long time. The medicine will be used alongside the usual treatment for depression. The study is for people who have been taking depression pills (antidepressants) for at least 8 weeks but haven't felt much better. Participants should have MDD or a similar condition and must be able to follow study rules.

Key Points:

• The study checks the safety of a new drug combined with regular treatment for depression.
• Participants need to have been taking antidepressants for at least 8 weeks.
• People with other main psychiatric disorders or at risk of harm are not included.

If you meet the criteria and are interested, talk to a doctor about joining. The study helps researchers understand if the new medicine is safe for long-term use.