In the long-term follow-up phase after week 8, patients who achieve remission or response will be followed up and the same dose will be administered throughout. Assessments will include the MADRS, the clinical global impression scale (CGI), and the Quick Inventory of Depressive Symptomatology self-reported (QIDS-SR) (weeks 1, 2, 3, 4, 6, 8, 12, 16, 20, and 24). Adverse events will also be monitored on every visit.