• Time to recurrence [ Time Frame: 52 to 54 weeks ] [ Designated as safety issue: No ]
  

• Recurrence rates [ Time Frame: 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Time to greater than or equal to 50% worsening in the 17-item Hamilton Depression Rating Scale and the Clinical Global Impressions of Severity [ Time Frame: 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Loss of response (HAMD greater than 9 and CGI-Severity greater than 2) at any time [ Time Frame: 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• HAMD-17 total score [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• CGI-Severity scale [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Patient's Global Impressions of Improvement (PGI-I) [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Hamilton Depression Rating Scale subscales, including the Core, Maier, Anxiety/Somatization, Retardation/Somatization, and Sleep subscales, and the depressed mood item. [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Visual Analog Scales (VAS) for pain [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Symptom Questionnaire-Somatic Subscale (SQ-SS) [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Sheehan Disability Scale (SDS) [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• 36-item Short-Form Health Survey (SF-36) [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Resource Utilization and Hospitalization Module [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: No ]
  
• Treatment-emergent adverse events [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: Yes ]
  
• Arizona Sexual Experience Scale (ASEX) [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: Yes ]
  
• Vital signs [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: Yes ]
  
• Laboratory measurements [ Time Frame: 4-10 weeks, 22-24 weeks and 52 to 54 weeks ] [ Designated as safety issue: Yes ]
  

Inclusion Criteria:

• Patient must be at least 18 years old.
• Patient must be diagnosed with depression and have had previous episodes of depression.
• Patient must sign informed consent.

Exclusion Criteria:

• Female and pregnant or breastfeeding.
• History of bipolar disorder, schizophrenia, or other psychotic disorders.
• Suffer from a serious medical illness (other than depression) or abnormal laboratory result that would require a change in medication, intervention, or hospitalization.
• Have been treated with a medication called monoamine oxidase inhibitor (MAOI) within 14 days of the start of the study, or potential need to use a MAOI within 5 days of finishing the study.
• Have taken an antidepressant called fluoxetine within 30 days of the start of the study.