Patient description: The patient is a 47-year-old Asian woman complaining of persistent feelings of sadness. She lost interest in activities she used to enjoy. She states that her mood is mostly depressed for the past 3 weeks. She also lost her appetite , which led to about 5kg weight loss. She complains of loss of energy and feelings of worthlessness nearly every day. She is not using any drugs and she does not smoke. She doesn't drink alcohol. 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 recently diagnosed with colon cancer and he is starting his chemotherapy. There is nothing remarkable in her past medical history and her drug history is only positive for Vit D3 1000 units daily. Her family history is negative for any psychologic problems. Her HAM-D score is 20.

Clinical trial eligibility criteria: eligible ages (years): 0.0-999.0,  Depressive Disorder Subjects meeting all of the following will be considered for enrollment into the study: Men or women, 18 to 65 years of age. A woman of childbearing potential must be using two medically accepted means of contraception. This can an oral or other hormonal contraceptive started at least 4 weeks prior to randomization plus a barrier method such as condoms or two barrier methods combined. Surgical sterilization of the subject or their partner is also considered acceptable. Hormonal therapies should be in place at least 4 weeks prior to randomization (V8). Women of childbearing potential must agree to a beta test at screening and during Visits 5, 7, 8, 9, 11 and 13 through 16. Each subject must have a level of understanding sufficient to agree to all tests and examinations required by the protocol. Subjects must be considered reliable (i.e., based on clinical judgment of the investigator the subject is able and willing to cooperate with study procedures (including compliance with medication, use of birth control appropriately, and attend study visits, etc). Each subject must understand the nature of the study and must sign an informed consent document. Subjects must fulfill the for major depression, without psychotic features as defined in DSM-IV based on clinical assessment and confirmed by structured diagnostic interview SCID-P. Subjects must have an initial score at Visit 1 and Visit 2 of at least 20 on the HAM-D (17). Subjects must have a total score of HAM-D at the end of the 6th week of escitalopram prospective screening of at least 17 (visit 5). Current major depressive episode of at least 4 weeks duration and for the current episode of major depression has a history of failure to respond to at least 4 weeks of any antidepressant medication such as SSRI, Wellbutrin, nefazodone/trazadone, MAOI, or venlafaxine/duloxetine at an adequate or clinically customary dose for antidepressant purposes prior to entering escitalopram screening. Informed consent must be obtained in writing for all subjects at enrollment into the study  Subjects presenting with any of the following will not be included in the study: No subjects who have previously been treated with the investigational product (M100907) will be enrolled in this study. Participation in a clinical trial of another investigational (nonmarketed) drug within 1-month (30 days) prior to study Visit 1. Female subjects who are either pregnant or breast-feeding or who do not appear reliable to use adequate contraception. Clinically significant cardiovascular, hepatic, endocrinologic (including but not limited to diabetes and uncorrected hypothyroidism or hyperthyroidism), neurological (including but not limited to epilepsy, stroke and sleep apnea), or other major systemic disease making implementation of the protocol or interpretation of the study results difficult Subjects with one or more past seizures without a clear and resolved etiology. DSM-IV substance abuse (except nicotine and caffeine) within the past 90 days and substance dependence within the past 2 years. Treatment with a reversible monoamine oxidase inhibitor, guanethidine, or guanadrel within 1 week prior to Visit 2. Treatment with any other concomitant medication with primarily CNS activity, other than specified in Appendix 2 1 day prior to randomization. Subjects are excluded if greater than four failed antidepressant trials in the past not including escitalopram (adequate dose and duration) during the index episode of major depression. An adequate trial is defined as 6 weeks of treatment with the antidepressant at a dosage considered therapeutic 159. The doses considered therapeutic are for fluoxetine 20-80 mg/day, paroxetine 20-60 mg/day, sertraline 100-200 mg/day, citalopram 20-40 mg/day, escitalopram 10-20 mg/day, fluvoxamine 100-300 mg/day, bupropion 300-450 mg/day, and venlafaxine 75-375 mg/day. Failure to respond to drugs with a 5-HT2 mechanism when added to SSRI including nefazodone, trazodone, mirtazapine/mianserin, SSRI + atypical neuroleptics (clozapine, risperidone, olanzapine, ziprasidone) at therapeutic doses for 4 weeks or longer. (the SSRI must be at clinically appropriate doses and the 5-HT2 antagonist must be at doses that antagonize a significant % of receptors (trazadone greater than 125 mg, nefazodone greater than 300 mg, mirtazapine greater than 30 mg, clozapine greater than 50 mg, risperidone greater than .5 mg, olanzapine greater than 5mg, ziprasidone greater than 20 mg). Treatment with electroconvulsive therapy (ECT) within 3 months prior to Visit 2. Current diagnosis of schizophrenia or other psychotic or bipolar disorder as defined in the DSM-IV. Judged clinically to be at serious risk of suicide based on HAM-D suicide item rating plus direct clinical questioning and assessment. History of drug or alcohol dependence in the last 2 years. Hepatic enzyme elevation greater than 2X normal Subjects who are taking drugs that could potentially interact with M100907 via the cyp 3A4 isoenzyme. Subjects with a corrected Q-T ECG interval greater than 450 for males and 470 for females on screening ECG (Bazett correction) History of hypersensitivity to the investigational products or to drugs with similar chemical structures. Likelihood of requiring treatment during the study period with drugs not permitted by the clinical study protocol. Excluded meds: Treatment with CYP 3A4 inhibitors (macrolide antibiotics, itraconazole, indinivir, ritinivir, ketoconazol, verapamil, propoxyphene, fluoxetine) or inducers (rifampicin, carbamazepine, phenobarbitol, phenytoin). Treatment with sedative hypnotics or drugs with 5-HT2A or 5-HT3 activity (clozapine, risperidone, olanzapine, quetiapine, trazodone, nefazodone, mianserin, mirtazapine, cyproheptadine, ondansetron, granisetron, dolasetron). Treatment with drugs that are known to significantly prolong the QT interval of the ECG. Mental condition rendering the subject unable to understand the nature, scope, and possible consequences of the study. Subjects unlikely to comply with protocol, (e.g., uncooperative attitude, inability to return for follow-up visits, and unlikelihood of completing the study). Subjects will not be allowed to receive psychotherapy during the trial.. Subjects may be included in the study only if they meet all of the and none of the  The investigator and Aventis must approve any waiver of these and on a case-by-case basis prior to enrolling the subject. Both Aventis and the investigator must document this. No subject will be allowed to enroll in this study more than once. The essential for entry are subjects who have at least moderate level of major depression (HAM-D = 20) who do not have psychotic depression and are resistant to treatment based on both retrospective and prospective rating are treatment refractory to specified antidepressants. Subjects are excluded who have failed antidepressants of similar mechanism to M100907. Female subjects must use two forms of birth control and subjects will be excluded based on medical outlined in the full list of and  No subjects who have previously been treated with the investigational product will be enrolled in this study