TRAIT-RS is an observational study to evaluate ongoing treatment response stability to standard of care antidepressant treatments (ADTs) among individuals who met criteria for Major Depressive Disorder (MDD) and completed the Tracking Response to Antidepressants in Advance of Investigational Trials (TRAIT) study (NCT04748276).

Inclusion Criteria:

• Participant has completed the TRAIT study and, in the opinion of the investigator, would benefit from ongoing depression monitoring and/or ADT treatment.
• Participant has signed an ICF prior to any study-specific procedures being performed.
• Participant is male or female of age ≥ 18 years.
• Participant is in good physical health and, in the opinion of the investigator, is a suitable candidate for treatment with an ADT.

Exclusion Criteria:

• Participant is pregnant, breast-feeding, or planning to become pregnant.
• A history or presence of a clinically significant hepatic, renal, gastrointestinal, cardiovascular, endocrine, respiratory, immunologic, hematologic, dermatologic, or neurologic abnormality, which, in the opinion of the investigator, may impact participant safety or study results.
• Participant has a history of any psychiatric condition other than MDD, which, in the opinion of the investigator, is primary or any other psychiatric or neurologic disorder or symptom that could pose undue risk to the participant or compromise the study.
• Any participant who represents an acute suicidal risk in the opinion of the investigator.
• Moderate or severe substance use disorder within 90 days prior to screen according to DSM-5 criteria that, in the opinion of the investigator, could pose undue risk to the participant or compromise the study.
• Any condition that, in the opinion of the investigator, makes the participant unsuitable for the study.

Adults who previously met the Diagnostic and Statistical Manual - Version 5 (DSM-5) criteria for Major Depressive Disorder (MDD), sought enrollment in an industry-sponsored antidepressant trial, achieved MDD symptom remission in the TRAIT study, and, in the opinion of the investigator, would benefit from ongoing depression monitoring and/or ADT treatment.