['major depressive disorder']
['pdc-1421 capsule', 'placebo']

        Inclusion Criteria:

          1. Outpatients aged 20-65 years

          2. Subjects must be able to understand and willing to sign informed consent

          3. Female subjects of child-bearing potential must test negative to pregnancy and use
             appropriate birth control method from the beginning of study to the 15 days later
             after ending of study

          4. Met criteria for MDD without psychotic features as defined by the Diagnostic and
             Statistical Manual of Mental Disorders, Fourth Edition Text Revision® (DSM-IV-TR) and
             confirmed by use of the Mini International Neuropsychiatric Interview (MINI).

          5. 17-item HAM-D (Hamilton Rating Scale for Depression) total score ≧20 and CGI (Clinical
             Global Impression) total score ≧4

        Exclusion Criteria:

          1. Have a current or previous major psychiatric disorders which be defined to be per the
             DSM-IV-TR, including obsessive-compulsive disorder, posttraumatic stress disorder,
             bipolar I or II, manic or hypomanic episode, schizophrenia, major Axis II disorders
             which might compromise the study, and major depression with psychotic symptoms, mental
             retardation.

          2. Use of any treatment for MDD in the last 2 weeks before visit 1 (4 weeks for
             fluoxetine).

          3. Use of psychoactive drugs within the last 2 weeks before visit 1 other than that
             subjects had insomnia who need the treatment as determined by the Investigator.

          4. Subjects who were non-responsive to two or more courses of antidepressant medications
             given an adequate dosage for symptom treatment within four weeks, or by the judgment
             of the investigator considered to have treatment resistant depression (TRD), or a
             history of electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS) or
             psychosurgery within the last year.

          5. Have a history of any seizure disorder.

          6. Any clinically significant abnormal vital sign, ECG, laboratory values as determined
             by the investigator which might interfere with the study.

          7. Any organic disorder caused u medical related depression which cannot be under
             well-controlled such as clinically significant in neurological, gastrointestinal,
             renal, hepatic, cardiovascular, respiratory, metabolic, endocrine, hematological or
             other major disorders

          8. Have a high suicidal risk as measured by MINI.

          9. Have a history of substance abuse within the past 6 months or a positive urine drug
             screen for any substance of abuse at visit 1.

         10. Have a history of severe allergies to more than 1 class of medication or multiple
             adverse drug reactions.
      