This study intends to conduct a prospective, double-blind, randomized, controlled trial. Adolescents aged 12-17 years old and American Society of Anesthesiologists (ASA) physical status I and II are selected as subjects. Oral probiotics is used as intervention before surgery, vital signs data, serum IL-1, IL-6, BDNF,5-HT and other inflammatory indicators are collected before surgery and after non-cardiac and non-gastrointestinal surgeries, and the incidence and degree of anxiety and depression are evaluated after non-cardiac and non-gastrointestinal surgeries. To determine the effect of esketamine on reducing anxiety and depression in adolescents after non-cardiac and non-gastrointestinal surgeries, and to provide an effective clinical basis for accelerating the rehabilitation of adolescents after non-cardiac and non-gastrointestinal surgeries.

Inclusion Criteria:

• 8 years ≤ age ≤17 years;
• Patients who plan to undergo elective surgery under general anesthesia, and the operation time is 1-2 hours;
• ASA grade I-II
• The body mass index falls within the normal range, which is 18.5 - 23.9 kg/m2.

Exclusion Criteria:

• The patient has psychological disorders, including but not limited to bipolar affective disorder.
• Eating disorder
• No informed consent form
• Due to certain serious diseases, one needs to take medication for a long period of time.
• Personality disorder
• Has undergone or needs to undergo gastrointestinal surgery
• Have taken antibiotics or probiotics within the past 8 weeks
• Pure vegetarian diet