Patient description: A 46-year-old Asian woman with MDD complains of persistent feelings of sadness and loss of interest in daily activities. She states that her mood is still depressed most of the days. She complains of loss of energy and feelings of worthlessness nearly every day. She is on anti-depressants for the past 6 months, but the symptoms are still present. She does not drink alcohol or smoke. She used to exercise every day for at least 30 min., but she doesn't have enough energy to do so for the past 3 weeks. She also has some digestive issues recently. She is married and has 4 children. She is menopausal. Her husband was diagnosed with colon cancer a year ago and is undergoing chemotherapy. Her past medical history is unremarkable. Her family history is negative for any psychologic problems. Her HAM-D score is 20.

Clinical trial eligibility criteria: eligible ages (years): 18.0-64.0,  Depressive Disorder, Major [At the start time of the run-in phase] Subject must have a primary diagnosis of major depressive disorder as classified by the DSM-IV-TR as below (however, to those accompanied by comorbid psychiatric disorders), and be showing currently a symptom of depression or depressive status: Major depressive disorder, single episode (296.2x); Major depressive disorder, recurrent (296.3x) Subject must have a total score of >=20 on the IVRS HAM-D (17 items) Subject must have a total score of >=25 on the IDS-SR Subject must have a score of >=1 on 4 out 5 items on the 5-item subscale of the IDS-SR (Item 19, 20, 21, 22 and 30), and a total score of >=7 on the 5-item subscale of the IDS-SR Subject must have a CGI-SI score of >=4 (i.e., Moderately ill or much worse) Subject must have the current depressive episode's duration of >=8 weeks but <24 months Subject is outpatient Subject must show QTc <450 millisecond (msec) or <480msec with Bundle Branch Block - values based on either single ECG values or triplicate ECG averaged QTc values obtained over a brief recording period Subject must show a value less than twice of the upper limit of normal value range of AST (GOT) and ALT (GPT), and a value <=1.5 times of the upper limit of normal value range of both Al-P and total bilirubin (however, subject who shows >35% of direct bilirubin with a value >=1.5 times of the upper limit of normal range of total bilirubin regards eligible)  [At the start time of Run-in phase (Visit 1)] Subject has predispositions to seizure: who currently has or has a past history of seizure or seizure disorder, more than a single febrile seizure in infancy, cerebral tumour, or head / brain injury (traumatic); who has a family history of idiopathic seizure; who is diabetic patient with treating by oral hypoglycaemics or insulin; who uses drugs lowering the threshold of seizure Subject has a history or current diagnosis of anorexia nervosa (DSM-IV-TR 307.1) or bulimia (DSM-IV-TR 307.51) Subject has a primary DSM-IV diagnosis of, or received treatment for, panic disorder, obsessive compulsive disorder (OCD), posttraumatic stress disorder (PTSD), or acute stress disorder within 12 months before the start time of Run-in phase Subject has a DSM-IV diagnosis of schizophrenia, or other psychotic disorder(s) including bipolar disorder Subject has a history of or currently has manic episode(s) Subject has any other DSM-IV axis II diagnosis that would suggest non-responsiveness to pharmacotherapy or non-compliance with the protocol (e.g., antisocial, borderline disorder or narcissistic personality disorder) Subject starting psychotherapy (except for supportive psychotherapy not aimed at therapeutic efficacy and unlikely to affect efficacy evaluation) or a cognitive behaviour therapy within 12 weeks before start time of the run-in phase Subject received electroconvulsive therapy (ECT) within 24 weeks before start time of the run-in phase Subject took MAO inhibitors (selegiline hydrochloride) within 2 weeks before start time of the run-in phase