A Study of Aticaprant in Adult and Elderly Participants With Major Depressive Disorder (MDD)

Inclusion Criteria

• •Transferred-entry participants:
• •Participants must have completed the double blind (DB) (expand DB) Treatment Phase of Study 67953964MDD3001 or Study 67953964MDD3002 without early treatment discontinuation or switch in the oral selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor (SSRI/SNRI) in the parent study
• •Direct-entry participants:
• •Have a Hamilton Depression Rating Scale (HDRS)-17 total score of 20 or higher at the first and second screening interviews and must not demonstrate a clinically significant improvement (that is, an improvement of more than 20 percent (%) on their HDRS-17 total score) between the first and the second independent HDRS-17 assessments
• •Have had an inadequate response to at least 1 oral antidepressant treatment, administered at an adequate dose (at or above the minimum therapeutic dose per Massachusetts general hospital antidepressant treatment response questionnaire \[MGH ATRQ\]) and duration (at least 6 weeks) in the current episode of depression
• •Must be an outpatient at open-label treatment phase baseline
• •Meet Diagnostic and Statistical Manual of Mental Disorders-5th Edition (DSM-5) diagnostic criteria for recurrent or single episode major depressive disorder (MDD), without psychotic features, based upon clinical assessment and confirmed by the Structured Clinical Interview for DSM-5 Axis I Disorders-Clinical Trials Version (SCID-CT)
• •Direct-entry and Transferred-entry Participants:
• •Participants should not take any prohibited medication or food supplements