Fig. 4From: Effects of a single subanesthetic dose of esketamine on postoperative subthreshold depressive symptoms in patients undergoing unilateral modified radical mastectomy: a randomised, controlled, double-blind trialChanges in preoperative and postoperative PHQ-9 scores between the two groups. The graph shows the mean and standard error of the perioperative PHQ-9 scores of the two groups, and scores of Group E and C at the same time point was compared with the Mann–Whitney U test. Group C, control group. Group E, esketamine group. PHQ-9, Patient Health Questionnaire-9. POD, postoperative day. Compared with the control group at the same time point, *P < 0.05Back to article page