Study Assessing the Safety and Therapeutic Effect of Buprenorphine in MDD Patients

Inclusion Criteria: * Outpatients and inpatients * Men and women 18-68 years of age. * Primary DSM-IV diagnosis of Major Depression, single or recurrent episode confirmed by the Structured Clinical Interview for the DSM-IV (SCID-IV), with the additional requirements of a current episode ≥4 weeks and CGI-S ≥4. * Total HDRS-21 ≥20 and Item 1 score ≥2 at the screening visit. * The patient did not respond to at least one antidepressant medication given for an accepted dose and duration. * If currently taking Benzodiazepines, the patient must be clinically appropriate to discontinue treatment with those agents, and able to tolerate no benzodiazepines during the study period. * Capable and willing to provide informed consent * Able to adhere to the treatment schedule. Exclusion Criteria: * Depression secondary to a general medical condition. * History of substance abuse or dependence within the past 6 month (except nicotine and caffeine). * All antidepressant medications, must have been in stable dosage for at least 6 weeks prior to entry into the study, with no anticipation of change over the duration of the study. * Use of any medication(s) listed on the Excluded medication list within the time that mansion for each medication on the list. * Any psychotic disorder (lifetime), including schizoaffective disorder, or major depression with psychotic features • Bipolar disorder • Eating disorder * Presence (within 12 months of baseline) of a personality disorder (such as antisocial, schizotypal, histrionic, borderline, narcissistic) as assessed by the investigator to be primary, causing a higher degree of distress or impairment than MDD. * Use of a Monoamine Oxidase Inhibitor (MAOI) within 2 weeks of the screening visit * Use of a CYP3A4 Inhibitors and CYP3A4 Inducers within 2 weeks of screening visit. * Present suicidal risk as assessed by the investigator or significant suicide risk based on HDRS-21 item 3 score of 3 or 4 or a history of attempted suicide in the last 6 month * Known or suspected pregnancy * Women who are breast-feeding * Women of childbearing potential and not using a medically accepted form of contraception when engaging in sexual intercourse. * Patients with severe respiratory insufficiency or asthma - anticipation require examination of pulmonologist. * Patients with severe hepatic or renal insufficiency. * Patients with history of head injury, increased intracranial pressure, hypotension, prostatic hypertrophy or urethral stenosis- anticipation require examination of neurologist.