Rapid Antidepressant Effects of Ketamine in Major Depression

Depressive disorders may be severe, chronic and often life-threatening illnesses. Impairment in physical and social functioning resulting from depression can be just as severe as other chronic medical illnesses. Recent preclinical and clinical studies suggest that the glutamatergic system is involved in the mechanism of action of antidepressants. This study examines whether ketamine can cause a rapid-next day antidepressant effect in patients with Major Depressive Disorder. This study was designed to address the questions: Does the NMDA antagonist ketamine produce rapid antidepressant effects in patients with treatment-resistant major depression? What are the neurobiological correlates of antidepressant response (examining multi-modal MRI, MEG, polysomnography and serum markers) Patients, ages 18 to 65 years with treatment-resistant major (unipolar) depression will in a double-blind crossover study receive either intravenous ketamine or saline solution.