Memantine to Reduce Neurocognitive Deficits Following Unilateral ECT for the Treatment of a Major Depression

Inclusion Criteria:: * Meets DSM-IV criteria for Major Depressive Disorder * 18 to 75 years of age and able to provide legal consent * Referred to Stanford ECT service by treating physician for unilateral electroconvulsive therapy with inpatient hospitalization * Competed process for consenting to the clinical use of ECT according to California State law * Females of childbearing potential will be required to use a double-barrier method of contraception, which includes foam and either condom and diaphragm, IUD, and/or implant during study.\
 Exclusion Criteria:- Treatment with ECT in the 6 months prior to screening * Meets criteria for drug or alcohol abuse or dependence in the 6 months prior to screening * Use of alcohol or illegal drugs within seven days of randomization or during study. Patients may be excluded for use during a period greater than 7 days, per study physician's discretion * Presence of unstable or untreated cardiovascular disease, hypertension, or endocrine disorder as determined by the investigator * use of antipsychotic, antidepressant, or other prescription medications unless dose is stable for at least 7 days prior to randomization. * Use of any investigational treatment within 30 days of randomization * Previous allergic reaction to memantine or drugs of similar chemical structure. * Women who are pregnant or breastfeeding are not advised to participate in the research study * Any neurological disorder or organic brain condition that would confound neurocognitive testing