The basic characteristics of delusions: 1. It is the patient who is very concerned about the content and object of the delusion and firmly believes in the truth of the delusion content; 2. Although the delusion does not have any factual basis, the patient cannot be persuaded and educated, nor can the patient be changed through judgment, reasoning and experience; 3. Although the content of the delusion does not match the reality, it is closely related to the patient’s personal interests, such as the patient s jealousy and delusions may be that the patient has a bad relationship with his partner or lover and is usually worried and afraid, and the occurrence of such delusions will clearly reflect the patient’s fear of abandonment; 4. It has nothing to do with cultural background and has no obvious connection with the patient’s education and social experience, and this feature can be distinguished from superstition and prejudice.