To evaluate the overall safety and tolerability profile of two dose levels of DVS-233 SR during 6 months of open-label treatment in elderly outpatients with major depressive disorder.

Inclusion Criteria:

• Outpatients men and women aged 65 years or older.
• Mini Mental State Examination score of 24 or above.
• Subjects must have a primary diagnosis of MDD based on the criteria in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), single or recurrent episode, without psychotic features, on study day 1, if depressive symptoms for at least 30 days prior to screening visit and minimum screening and study day -1 (baseline) scores of 16 on the Hamilton Psychiatric Rating Scale for Depression (HAM-D17).

Exclusion Criteria:

• Significant risk of suicide based on clinical judgment, including common suicidal thoughts, and suicide being considered as a possible solution, even without specific plans or intention.
• Current (within 12 months of baseline) psychoactive substance abuse or dependence (including alcohol), manic episode, posttraumatic stress disorder, obsessive-compulsive disorder, or a lifetime diagnosis of bipolar or psychotic disorder as assessed by the modified Mini International Neuropsychiatric Interview (MINI). Current (within 12 months of baseline) generalized anxiety disorder, panic disorder, or social anxiety disorder as assessed by the modified MINI and considered by the investigator to be primary, causing a higher degree of distress or impairment than MDD. Presence (within 12 months of baseline) of a clinically important personality disorder (such as antisocial, schizotypal, histrionic, borderline, narcissistic). Presence of dementia.
• Depression associated with the presence of an organic mental disorder due to a general medical condition or a neurologic disorder.

Other exclusion applies.