CONCERTA® (Methylphenidate Hydrochloride) as add-on Therapy in the Treatment of Adult Major Depressive Disorder.

The purpose of this study is to evaluate the effects of the addition of CONCERTA® (methylphenidate hydrochloride, a central nervous system (CNS) stimulant) or placebo in adult outpatients with Major Depressive Disorder who are currently being treated with oral antidepressant medication (selective serotonin reuptake inhibitors or selective norepinephine reuptake inhibitors). The general symptoms of depression will be evaluated, as measured by the Montgomery Asberg Depression Rating Score (MADRS) on fatigue, energy, and overall severity of illness. The safety and tolerability of the CONCERTA® and antidepressant combination therapy will also be assessed.