Efficacy and Safety Study of Vortioxetine (Lu AA21004) for Treatment of Major Depressive Disorder

Inclusion Criteria

• Suffers from Major Depressive Disorder as the primary diagnosis according to Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) criteria (classification code 296.2x and 296.3x).
• The reported duration of the current major depressive episode is at least 3 months at the Screening Visit.
• Has a Montgomery-Åsberg Depression Rating Scale (MADRS) total score ≥26 at the Screening and Baseline Visits.
• Has a Clinical Global Impression Scale-Severity (CGI-S) score ≥4 at the Screening and Baseline Visits.

Exclusion Criteria

• Has one or more of the following conditions:
• Any current psychiatric disorder other than Major Depressive Disorder as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR; assessed by the Mini International Neuropsychiatric Interview: MINI). A participant who exhibits symptoms of anxiety is eligible unless fulfilling the diagnostic criteria for a current anxiety disorder per DSM-IV-TR.
• Current diagnosis or history of manic or hypomanic episode, schizophrenia or any other psychotic disorder, including major depression with psychotic features, mental retardation, organic mental disorders, or mental disorders due to a general medical condition as defined in the DSM-IV-TR.
• Current diagnosis or history of any substance-related disorder (except nicotine and caffeine-related disorders) as defined in the DSM-IV-TR. Participant with confirmed positive urine drug screens (except prescribed medications or a medication that does not constitute drug abuse) will be excluded.
• Presence or history of a clinically significant neurological disorder (including epilepsy).
• Neurodegenerative disorder. (Alzheimer's disease, Parkinson's disease, multiple sclerosis, Huntington's disease, etc.)
• Any DSM-IV-TR axis II disorder that might compromise the study.
• The current depressive symptoms of the participant are considered by the investigator to have been resistant to 2 adequate antidepressant treatments of at least 6 weeks duration each.
• Has received electroconvulsive, vagal nerve stimulation, or repetitive transcranial magnetic stimulation therapy within 6 months prior to the Screening Visit.
• Is currently receiving formal cognitive or behavioral therapy, systematic psychotherapy, or plans to initiate such therapy during the study.
• Is at significant risk of suicide or has a score ≥5 on Item 10 (suicidal thoughts) of the MADRS, or has attempted suicide within 6 months prior to the Screening Visit.