Patients with a primary diagnosis other than MDD.

Patients with a history of schizophrenia, schizoaffective disorders, seizure disorders or bipolar affective disorder.

Patients receiving formal psychotherapy or cognitive/behavioral therapy concurrently or in the 12 weeks prior to screening visit.

Patient is actively suicidal.

Patients who have a history of migraine headaches.

A Study Of A New Medicine (GW597599B) For The Treatment Of Major Depressive Disorder