Effects of Low Dose Ketamine Given at Induction of Anesthesia on Postoperative Mood in Patients With Depressive Symptoms

Ketamine has been shown to have an antidepressant effect when given intravenously in doses of 2mg/kg. Ketamine is used as a standard induction drug during general anesthesia. It is known in this instance to decrease postoperative pain. No one has studied whether or not ketamine when given in doses used during general anesthesia (0.5mg/kg intravenous) has an antidepressant effect on surgical patients who suffer from depression. The study is designed to determine whether or not a small dose of ketamine when given at the induction of anesthesia could have an antidepressant effect on surgical patients with depression.