The study consists of a 12-week open-label, flexible-dose treatment period with vortioxetine, followed by a 26-week, randomized, double-blind, fixed-dose, placebo-controlled relapse-prevention period. There will be a safety follow up 4 weeks after the end of the 26-week double-blind treatment period.
The study population will include 'de novo' participants as well as 'rollover' participants from other paediatric vortioxetine studies 12709A (NCT02709655) and 12712A (NCT02871297), who, in the investigator's opinion, could benefit from continued treatment with vortioxetine.