Major depression is a serious public health concern that contributes to significant morbidity and mortality. Despite the availability of a wide range of antidepressant drugs, a proportion of patients with major depression fail to respond to first-line antidepressant treatment, despite adequate dosage, duration, and compliance. Recent studies suggest that the glutamatergic system may play a role in the pathophysiology and treatment of depression. Memantine and other agents which reduce glutamatergic neurotransmission may represent a novel class of antidepressants.