This randomised , double-blind , 12-week study compared efficacy and tolerability of flexible-dose treatment with vortioxetine ( 10-20 mg/day ) versus agomelatine ( 25-50 mg/day ) in major depressive disorder patients with inadequate response to selective serotonin reuptake inhibitor ( SSRI ) / serotonin-noradrenaline reuptake inhibitor ( SNRI ) monotherapy .