Patients will be assigned randomly either to a treatment group or a placebo groups. All patients in both groups will be receiving standard ECT. The treatment group will receive memantine. All patients will be given a battery of cognitive tests and test of depression before ECT treatments start, after the 6th ECT treatment and after the completions of ECT. An analysis will be performed to see if memantine causes any impact on the response to ECT and prevents memory and cognitive impairment.