• Young Mania Rating Scale (YMRS) [ Time Frame: Day0, Day1, Day4, Day7, Day10, Day14, Day21 ] [ Designated as safety issue: No ]
  

• Clinical Global Impression - Bipolar Version (CGI-BP) [ Time Frame: Day1, Day4, Day10, Day14, Day21 ] [ Designated as safety issue: No ]
  

Inclusion Criteria:

• Trial subjects will be men and women of age 18 or above and below the age of 65 who will not be turning 65 during the trial.
• Patients have the ability to understand and to provide informed consent to the examination, observation, and evaluation processes specified in this protocol, and have signed the informed consent form based on a full understanding of the trial.
• Patients who meet DSM-IV-TR criteria for manic or mixed episodes and have been diagnosed as having "296.4x Bipolar I Disorder in which the most recent episode was manic" or "296.6x Bipolar I Disorder in which the most recent episode was mixed"
• Patients with a YMRS total score of 20 or more

Exclusion Criteria:

• Patients presenting with a clinical picture and/or history that is consistent with a DSM-IV-TR diagnosis of:

  • Delirium, dementia, amnestic disorder, or other cognitive disorders
  • Schizophrenia or other psychotic disorder
  • Personality disorder
• Patients experiencing their first manic or mixed episode
• Patients whose current manic episode has lasted for more than 4 weeks
• Patients with psychotic symptoms that are clearly due to another general medical condition or direct physiological effects of a substance
• Patients who have met DSM-IV-TR criteria for a substance-related disorder within 3 months (90 days) prior to informed consent (excluding caffeine- and nicotine-related disorders, but including abuse of benzodiazepines)
• Patients who have received ECT treatment within 8 weeks prior to informed consent
• Patients who are expected to require administration of ultrashort-acting or short-acting benzodiazepine receptor agonist hypnotics and antianxiety drugs (See (1) of 4.2.2) at doses exceeding the equivalent of 15 mg/day of diazepam (Only for those patients using such drugs)
• Patients at significant risk of developing a severe adverse event. Patients who have a medical condition that would interfere with assessments of safety or efficacy during the course of the trial, or who have a history of such a condition.

• Patients who have received any of the following treatments during the screening period:

  • Reserpine
  • Levodopa, dopamine receptor stimulants
  • Monoamine oxidase inhibitors
  • Psychostimulants
  • Thyroid hormones, antithyroid drugs
  • Corticosteroids (other than topical preparations)
  • Adrenaline
  • All other investigational or unapproved agents
  • ECT
  • Light therapy
• For patients who take lithium, valproate, or carbamazepine within 3 days prior to commencement of investigational product administration, those patients with serum concentrations of lithium greater than 0.6 mmol/L, serum concentrations of valproate greater than 50 µg/mL, or serum concentrations of carbamazepine greater than 4 µg/mL
• Patients judged to have a diabetic blood glucose level (judgment based on use of a self-monitoring blood glucose meter permissible), or patients whose HbA1c is 6.5% or higher
• Patients with a history or a complication of diabetes