A Fixed Dose Study of Adjunctive Treatment to Antidepressant Therapy for Adults With Major Depressive Disorder

The primary purpose of this study is to assess whether at least 1 dose of LY2216684 (12 milligrams \[mg\] or 18 mg once daily) is superior to placebo once daily in the adjunctive treatment of participants with major depressive disorder (MDD) who were identified as partial responders to an adequate course of treatment with a selective serotonin reuptake inhibitor (SSRI) during an 8-week, double-blind, acute adjunctive treatment phase.