A randomised controlled study of an N-Methyl-D-Aspartate antagonist in major depression

INTERVENTION: Ketamine IV. – bolus dose 0.25mg/kg then infusion at 0.25 mg/kg/hr for 45 minutes Washout 3 weeks. Follow‐ups at 1,7,14,21 days. Study duration 42 days. CONDITION: Depression Major depressive disorder PRIMARY OUTCOME: Montomery‐Asberg Depressive Rating Scale (MADRS) SECONDARY OUTCOME: BDNF plasma concentration Functional connectivity measured with electroencephalography (EEG) INCLUSION CRITERIA: * Participant is willing and able to give informed consent for participation in the trial. * Male or female, aged 18 years or above and less than 60. * In the Investigators’ opinion, is able and willing to comply with all trial requirements. * Major depressive disorder for at least three months, as assessed by a Clinical Interview using DSM‐IV criteria * MADRS >20 * An inadequate response to at least two antidepressants courses (Antidepressant Treatment History Form) one of which can include the current episode * Stable on antidepressant medication for four weeks prior to Study Day 1