Study Of GW679769 In Major Depressive Disorder

Inclusion criteria: * Subjects must have the ability to comprehend the key components of the consent form. * Subject must have met DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision) criteria for current MDE (major depressive episode) for at least 8 weeks prior to the Screening Visit. * If female, subjects must be practicing an acceptable method of birth control. * Subjects must have rating scores as outlined. Exclusion criteria: * Subjects whose symptoms of the MDE are better accounted for by another diagnosis. * Subjects with a history of schizophrenia, schizoaffective disorders or bipolar disorder. * Subjects have a positive urine test for illicit drug use and/or a history of substance abuse or alcohol dependence within the past 12 months. * Subjects with an unstable medical disorder. * If female, pregnant or lactating. * Subjects who have received ECT (electroconvulsive therapy) or TMS (transcranial magnetic stimulation) within the 6 months preceding screening or who have ever been homicidal.