With the continuous improvement of medical technology

surgery is becoming an important means to treat diseases for more and more patients. As there may be pains

anesthesia-related risks

the loss of body organs

surgical trauma

and postoperative complications in the perioperative period

most patients can feel varying degrees of worry

tension

and fear

or experience low mood

disappointment

cry

reduced activity level

and slow thinking and cognition. These psychological stress responses

collectively termed preoperative anxiety and depression

via activating the hypothalamic-pituitary-adrenocortical system and the locus coeruleus-sympathetic-adrenomedullary system

can promote neuroimmune inflammation

damage the blood-brain barrier

aggravate perioperative pain

and cause sleep disturbance. These events facilitate the release of 5-hydroxytryptamine

cortisol

and inflammatory cytokines

and eventually lead to perioperative neurocognitive disorders（PND）. PND can prolong the length of hospitalization

increase hospitalization costs

delay recovery from disease

and increase perioperative mortality.We now have a more and more clear understanding of the seriousness of PND. This review describes the causes and pathophysiological mechanisms of preoperative anxiety and depression and PND

and summarizes the relationship between the two conditions.