Perioperative depression symptom (PDS) is one of the common mental comorbidity, and influences the clinical outcomes and prognosis. However, there is no rapid acting treatment to deal with it during the limited hospital stay. This study aims to determine whether ketamine could improve the depressive symptom of peirioperative patients. It will also examine the safety for administrating ketamine as an antidepressant intraoperatively. Meanwhile, it will show if ketamine could improve anxiety, postoperative pain or delirium. This trial also will bring great concerns on patients with perioperative mental health and explore the measures to improve their psycho-related prognosis.

Inclusion Criteria:

1. Brain tumor located supratentorial area and need to receive elective craniotomy;
2. Moderate to severe depressive symptom measured by the qualified psychiatric doctors.
3. Ages between 18 and 65 years old.
4. American Society of Anesthesiologists physical status I-III

Exclusion Criteria:

1. History of epilepsy;
2. Major depression disorder patients undergoing antidepressive therapy within 2 weeks; 3 Psychiatric illness; 4 Drug abuse; 5 History of allergy to the research drug; 6 Tumor located in the Wernick area, Broca area or the frontal pole; 7 Hyperthyroidism; 8 Patients can not cooperate with investigators on psychiatric assessments; 9 Pregnant or breast-feeding woman; 10 refuse to sign inform consent.