Any current psychiatric disorder other than Major Depressive Disorder (MDD) as defined in the DSM-IV TR

Any substance disorder within the previous 6 months

Female patients of childbearing potential who are not using effective contraception

Use of any psychoactive medication 2 weeks prior to screening and during the study

Randomisation Criteria: Patients in remission (MADRS total score \<=10) at both Week 10 and Week 12

Efficacy of Vortioxetine (Lu AA21004) in the Prevention of Relapse of Major Depressive Episodes