A Study to Evaluate the Efficacy and Safety of JNJ-42847922 as Adjunctive Therapy to Antidepressants in Adult Participants With Major Depressive Disorder Who Have Responded Inadequately to Antidepressant Therapy

The study will investigate the antidepressant effects of a range of doses of JNJ-42847922 (seltorexant) (versus placebo), as adjunctive treatment to antidepressant drugs for treatment of MDD, and will assess the safety and tolerability of JNJ-42847922. The study will be conducted in 3 phases: a screening phase (up to 4 weeks), a double-blind treatment phase (6 weeks), and a post-treatment follow-up phase (2 weeks). Efficacy, safety, pharmacokinetic, and biomarker evaluations will be performed in the study at defined timepoints. The duration of the study will be up to approximately 12 weeks (84 days).