['bipolar depression']
['placebo', 'sm-13496', 'sm-13496']

        Inclusion Criteria:

          -  Patients who were fully informed of and understand the objectives, procedures, and
             possible benefits and risks of the study and who provided written voluntary consent to
             participate in the study.

          -  Outpatients aged 18 through 74 years at the time of consent

          -  Patients meets DSM-IV-TR criteria for bipolar I disorder, most recent episode
             depressed (≥ 4 weeks and less than 12 months) without psychotic features.

        Exclusion Criteria:

          -  Patients with imminent risk of suicide or injury to self, others, or property.

          -  Patients who had been hospitalized because of a manic or mixed episode within 60 days
             prior to screening.

          -  Patients who are otherwise considered ineligible for the study by the investigator.
      