Ketamine is a noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist that has attracted wide-spread attention for its rapid-onset antidepressant effects,especially in individuals with treatment-resistant depression and suicidal ideation [1-3].Compared with the traditional antidepressants that take weeks,if not months,to benefit patients and are associated with a high rate of relapse,ketamine exerts its antidepressant effects within several hours.These clinical benefits can last for 2 weeks after a single injection [1,2,4].However,ketamine still has limited clinical application,mainly because of its psychotomimetic side-effects and liability of abuse.