A study to assess the safety and effect of TC-5214 in patients with major depressive disorder.

Exclusion Criteria

• - Patients with a lifetime history of bipolar disorder; psychotic disorder or post-traumatic stress disorder.
• - Patients with a history of suicide attempts in the past year and/or seen by the investigator as having a significant history of risk of suicide or homicide.
• - Patients with any significant unstable hepatic, renal, pulmonary, cardiovascular, ophthalmologic, neurologic, or any other medical conditions that might confound the study or put the patient at greater risk during study participation.
• - History of stroke or transient ischemic attack, seizures or seizure disorder, head trauma including closed head injury.
• - Pregnancy or lactation.