Open Study Assessing the Feasibility of Minocycline in Patients With Unipolar Depression

Inclusion Criteria: 1. Outpatients and inpatients 2. Men and women 18-68 years of age. 3. Primary DSM-IV diagnosis of 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. 4. Total HDRS-21 ≥20 and Item 1 score ≥2 at the screening visit. 5. The patient did not respond to at least one antidepressant medication given for an accepted dose and duration. 6. Capable and willing to provide informed consent 7. Able to adhere to the treatment schedule. \- Exclusion Criteria: 1. Depression secondary to a general medical condition. 2. History of substance abuse or dependence within the past 6 month (except opioids, nicotine and caffeine). 3. All antidepressant medications, must have been in stable dosage for at least 3 weeks prior to entry into the study, with no anticipation of change over the duration of the study. 4. Use of any medication(s) listed on the Excluded medication list within the time that mansion for each medication on the list. 5. Any psychotic disorder (lifetime), including schizoaffective disorder, or major depression with psychotic features • Bipolar disorder • Eating disorder 6. Subjects who were taking a known contraindication to minocycline treatment. 7. Subjects who had received treatment with minocycline or β-lactam antibiotics in the preceding half year before study entry. 8. 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 9. Known or suspected pregnancy or women of childbearing potential and not using a medically accepted form of contraception when engaging in sexual intercourse.(if using oral contraceptives, during the minocycline treatment, subject should use an additional contraceptives), or women who are breastfeeding 10. Patients with severe hepatic or renal insufficiency. \-