IRCT20210125050137N1 IRCT 2021-02-06 Kashan University of Medical Sciences The efficacy of Ketamine on treatment-resistant depression's symptoms The efficacy comparison of single-dose vs. multi-dose of Ketamine on treatment-resistant depression's symptoms; a non-inferiority RCT study 2021-02-19 anticipated 30 Complete https://irct.ir/trial/53906 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Participants are randomized in two parallel groups by Permuted Block Randomization using (block size = 4) random number table, they receive single or multi dose ketamine , Blinding description: Health care personnel, including physicians, patient care and follow-up, data collection and data analysis officers, have been blinded in this study. The method of drug distribution among patients is block randomization. 2 Resistant depression. Intervention 1: In the first intervention group: patients are treated with a single dose of ketamine. In this group, ketamine is received only once, 50 cc of normal saline, which contains 0.5 mg per kg of body weight of ketamine hydrochloride, by pump or micro set within 40 minutes intravenously. Vial ketamine 10cc / 500 mg used by the company Rotex Medica is German. Intervention 2: Intervention group: Intervention group 2: Patients with multiple doses twice a week for up to 3 weeks receive 50 cc of normal saline containing 0.5 mg per kg body weight of ketamine hydrochloride intravenously by pump or micro set for 40 minutes. Ketamine 10cc / 500mg is used by the German company Rotex Medica. No - There is not a plan to make this available Justification or reason for not sharing IPD is The information of the study participants is confidential