Self-awareness (insight) refers to the patient’s ability to recognize the state of the disease he or she is suffering from, which includes both awareness of the body and awareness of mental activities. Patients with major physical illnesses have the ability to recognize their physical illnesses correctly and have the desire to seek treatment; however, unfortunately, patients with mental illnesses have no or little ability to recognize their mental illnesses, and most patients with mental illnesses tend to believe that they are being framed, that others are sorry, and that they are normal, and will not take the initiative to receive psychiatric treatment. (1) Self-knowledge disorder (1) can correctly recognize their own psychopathic state is said to have self-knowledge. (2) Thinking that one’s psychopathic state is not pathological is called no self-knowledge. (3) Between the two is called partial self-knowledge. 2. Criteria for judging the presence or absence of self-knowledge 1) The patient is aware of phenomena that others consider abnormal. (2) The patient himself recognizes that these phenomena are abnormal. 3）The patient recognizes that these abnormalities are the result of his or her own mental illness. 4）The patient realizes that treatment is necessary. 3. Characteristics of self-knowledge recovery in patients with mental disorders 1) Most patients with mental disorders have incomplete self-knowledge and often deny having the disease and refuse treatment. (2) The gradual recovery of patients’ self-knowledge with the progress of treatment is one of the main indicators of the tendency of mental illness to remission. (3) However, it is undeniable that some patients do not recover their self-knowledge satisfactorily, and these patients are unable to adhere to their medication, resulting in recurrent illness. (4) Critical period for recovery of self-knowledge (1) Patients with their first episode of mental illness should receive psychotherapy along with medication as a critical period for recovery of self-knowledge. (2) If self-knowledge is not restored in the first treatment, the risk of relapse increases, and it is more difficult to restore self-knowledge when receiving treatment again. (3) Early detection, diagnosis and treatment are the key to the prevention and treatment of mental illness.