Thinking is the reflection of the human brain to the objective things indirectly generalized, it can reveal the inner, essential characteristics of things, is the highest form of human cognitive activities. Thinking includes analysis, synthesis, comparison, abstraction, generalization, judgment and reasoning and other basic processes. Normal thinking has: 1, purposeful: refers to thinking around a certain purpose, and solve a problem. 2, coherence: refers to the concept of the thinking process backward and forward, interconnected. 3, logical: refers to the thinking process in line with the laws of logic, there is a certain amount of reason. 4, practical: refers to the thinking can pass the test of objective practice. Delusion (delusion) is a thought content disorder, it is a pathological distorted beliefs formed on the basis of pathological reasoning and judgment. The characteristics of delusion include: 1. The content of delusion does not match the facts and lacks the basis of objective reality, but the patient is still convinced. 2. The delusional content involves the patient himself or herself and has a personal stake, “others are talking about me (myself), “someone is following and spying on me (myself)”. 3. The delusional content is individually unique and is an individual psychological phenomenon, not a collective belief. 4. The delusional content is related to the patient’s cultural background and experience, and is usually strongly colored by the times. Delusions should be distinguished from fantasies. Fantasy is a surreal reverie, a form of thinking that combines different elements or contents together. When some people encounter frustration or intractable problems, they tend to think about it and put themselves into an imaginary world to cope with the frustration and gain psychological satisfaction. However, delusions usually have a certain purpose and are easily corrected. Delusion of reference Patients believe that things that happen in their surroundings that are not related to them are related to them. For example, they may think that people around them are talking about them, or that other people’s coughing is directed at them, or even that what is broadcast on TV or published in newspapers is related to them. Delusion of persecution: The patient is convinced that he or she is being persecuted by certain people or organizations, such as poisoning, stalking, surveillance, slander, etc. The patient may be affected by delusion of persecution. Under the influence of delusion, patients may refuse to eat, run away, call the police, injure themselves, hurt others, etc. If you find any of these manifestations, you must seek a specialist to give confirmation for early detection and diagnosis to facilitate early recovery from the disease.