will receive a single dose of ketamine 0.5 mg/kg i.v. plus 2 ml normal saline, at 5 minutes after the induction of anesthesia

will receive dexamethasone 0.5 mg/kg i.v. plus 2 ml normal saline, at 5 minutes after the induction of anesthesia

will receive ketamine 0.5 mg/kg i.v. and dexamethasone 0.5 mg/kg i.v., at 5 minutes after the induction of anesthesia

After receiving by IRB approval and obtaining informed consent from patients, 93 patients who were aged between 18 and 70 years old and classified as American Society of Anesthesiologists (ASA) classes I and II. Afterward, the patients are randomly (sealed envelopes) allocated into one of three treatment; Group K (n = 31) receives a single dose of ketamine 0.5 mg/kg i.v. plus 2 ml normal saline, Group D (n = 31) receives dexamethasone 0.5 mg/kg i.v. and a maximum dose of 8 mg plus 2 ml saline, and Group KD (n = 31) receiveds ketamine 0.5 mg/kg i.v. and dexamethasone 0.5 mg/kg i.v. at 5 minutes after the induction of anesthesia in a double-blinded method.

Anesthesiologist performed the assessment of perioperative depressed mood change with use of Patient Health Questionnaire-9 (PHQ-9). The PHQ-9 is the depression module, which scores each of the nine DSM-IV criteria as "0" (not at all) to "3" (nearly every day) with a total score ranging from 0 to 27; 0-4 none, 5-9 mild, 10-14 moderate, 15-19 moderately severe, 20-27 severe depressed mood

The VAS consisted of a straight line with the left end of the line representing no pain and the right end of the line representing the worst pain. Patients were asked to mark the position on the line corresponding to their perception of pain. The VAS score for pain was measured with intervals of 1, 6, 24, and 48 hours after surgery.