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

This is a 12 week multi-center, double-blind, placebo-controlled study on the efficacy of LY2216684 augmentation of selective serotonin reuptake inhibitors (SSRIs) in participants with MDD who have a partial response to treatment with an SSRI. While remaining on a steady dose of their SSRI treatment at entry into the study, participants will be randomly assigned to adjunctive treatment with LY2216684 or placebo in a 1:1 ratio for 10 weeks of acute treatment.