- Male or female outpatients aged 18 years or older who are fluent in written and spoken
English.
- A primary diagnosis of MDD based on the criteria in the Diagnostic and Statistical
Manual of Mental Disorders, 4th edition (DSM- IV-TR), single or recurrent episode,
without psychotic features.
- A HAM-D17 total score ≥20 at the screening and baseline (study day -1) visits and no
more than a 4-point improvement from screening to baseline.
- Significant risk of suicide based on clinical judgment.
- Current (within 12 months before 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.
- Current generalized anxiety disorder, panic disorder, or social anxiety disorder.
- History or current evidence of gastrointestinal disease known to interfere with the
absorption or excretion of drugs or a history of surgery known to interfere with the
absorption or excretion of drugs.
- Any unstable hepatic, renal, pulmonary, cardiovascular, ophthalmologic, neurologic, or
other severe acute or chronic medical or psychiatric condition or laboratory
abnormality that may increase the risk associated with study participation or
investigational product administration or may interfere with the interpretation of
study results.