The study aims to compare the antidepressant effects of a dextromethorphan-bupropion combination versus standard SSRI therapy in adult patients with major depressive disorder. Participants will be randomized into two groups: one receiving dextromethorphan-bupropion and the other receiving an SSRI (e.g., sertraline or escitalopram). Treatment will last for 6 weeks, with assessments at baseline and study completion. The primary outcome will be the remission rate measured by a validated depression rating scale. Secondary outcomes include change in depressive symptoms severity and safety/tolerability measures.

Inclusion Criteria:

Diagnosed with major depressive disorder (MDD) per DSM-5 criteria.

Baseline depression score indicating moderate to severe depression

Ability to provide informed consent

Willing to comply with study requirements

Exclusion Criteria:

History of bipolar disorder, schizophrenia, or other psychotic disorders

Current substance use disorder (within past 6 months)

Active suicidal ideation requiring urgent intervention

Pregnancy or breastfeeding

Known hypersensitivity to study medications

Individual participant data will not be shared due to confidentiality concerns and lack of infrastructure for data sharing.