Safety and Efficacy of Cariprazine as an Adjunctive to Antidepressant Therapy in Major Depressive Disorder

Inclusion Criteria: * Male or female outpatients 18 to 65 years of age, inclusive. * Currently meet the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria for moderate to severe major depressive disorder (MDD). * Current major depressive episode of at least 8 weeks and not exceeding 24 months in duration. * Ongoing inadequate response to protocol allowed antidepressant therapy (ADT). Exclusion Criteria: * Principal DSM-IV-TR-based diagnosis of an axis I disorder, other than MDD, * Women who are pregnant, or planning to become pregnant or breastfeed during the study or not practicing reliable contraception that will continue through out the study. * History of meeting DSM-IV-TR criteria for: 1. Depressive episode with psychotic or catatonic features. 2. Manic, hypomanic or mixed episode, including bipolar disorder and substance induced manic, hypomanic or mixed episode. 3. Schizophrenia, schizoaffective, or other psychotic disorder. 4. Obsessive-compulsive disorder. 5. Bulimia or anorexia nervosa. 6. Dementia, amnesic, or other cognitive disorder. 7. Mental retardation. * Participants considered a suicide risk.