According to psychiatric textbooks and diagnostic criteria, OCD is a chronic mental disorder in which obsessive-compulsive symptoms are the main clinical phase. Therefore, to recognize OCD, it is necessary to recognize obsessive-compulsive symptoms. Based on my observation of OCD and the recognition of obsessive-compulsive symptoms, I believe that the clinical manifestations of OCD include three aspects of symptoms that are closely related to each other. The first symptom is a cognitive domain symptom that has the effect of triggering the second two symptoms, so I call it the “initiation” or “initial” symptom, which is a spontaneous but involuntary intrusion into the domain of consciousness, i.e. The “mind” is filled with worries, fearful or extremely disgusting thoughts, ideas or representations. These initial symptoms lead to a second aspect of symptoms – emotional reactions, i.e., essentially similar experiences of anxiety or irritability. The appearance of such emotional symptoms is immediately followed by a third aspect of symptoms – behavioral response symptoms, i.e., two behavioral responses: verifying the recurrence of these initial symptoms in the cognitive domain and trying to counteract the emotional symptoms such as anxiety caused by the initial symptoms. The first aspect of the cognitive domain is the so-called “obsessive thinking”, the third aspect of the behavioral response is the “compulsive behavior”, and the intermediate link between the two is the emotional symptom. The relationship between the three is that the compulsive thinking that occurs involuntarily leads to anxiety, and in order to reduce anxiety, the patient takes the initiative (autonomously) to adopt or implement compulsive behaviors with the purpose of reducing anxiety. This compulsive behavior can be either “outward” or observable simple or complex actions or even extremely complex “ritualized” behaviors, or “inward” or unobserved inner psychological behaviors. It can also be an “internal” or unobserved mental process such as counting, praying, “cursing,” etc. In the case of OCD with obsessive-compulsive fear, for example, the symptoms are related to each other in this way: the fear that he or she may have done something to hurt another person suddenly appears in the patient’s mind, and he or she begins to worry about the consequences of this behavior, leading to an emotional response of anxiety and fear. The patient then becomes irritable about why he or she is worried, and tries to verify that such worries will not recur for no apparent reason. Because the patient is clearly dominated by anxiety at this time, he or she focuses on the experience, resulting in the recurrence of such fears and increasing anxiety and irritability. On the other hand, the patient may also try to verify that he or she has actually committed harm to another person in a way that he or she recognizes, such as carefully observing the emotional behavior of the person he or she has “harmed” and the various reactions of people present at the time to confirm that he or she has not committed such harm. The obsessive-compulsive symptoms of OCD patients can be varied, but the basic pattern is the “trilogy” described above. However, as the illness worsens and lengthens, the frequency of obsessive-compulsive thoughts becomes more frequent and the patient’s ability to implement compulsive behaviors to reduce anxiety becomes less effective. Furthermore, over the long course of the illness, obsessive-compulsive thoughts and behaviors can shift, for example, from worrying about not locking the door to worrying about contaminating oneself with viruses, bacteria, or chemical contaminants that may cause illness, and the corresponding compulsive behaviors can change from verification behaviors to washing behaviors. Obsessive-compulsive thinking can also be generalized, for example, at the beginning of the illness there may be only the obsessive-compulsive thinking of worrying about getting sick from viruses and bacteria, but later on there is a fear of getting sick from both microorganisms and chemical toxins, and even a fear of getting sick from inhaling harmful ingredients in the air. Therefore, OCD is a chronic mental disorder with an extremely complex and prolonged course. My understanding of OCD is mainly related to my realization that humans have a psychological characteristic of fear of death. I believe that OCD is probably the only disorder or mental disorder that occurs in people. I think that some of the following psychosocial factors are important for the creation of obsessive-compulsive symptom things and the occurrence of OCD: Humans are the only animals in the world that deeply understand the meaning of death and can communicate it interpersonally with verbal words, images, expressions postural movements, and other communication methods. Because of understanding the meaning of death, there must be varying degrees of fear of death. Any individual who understands the meaning of death will transmit this fear to the receiver at the same time when transmitting the message of the meaning of death. Since adults, especially older adults, are closer to death than children and adolescents, have seen more death events, have a deeper understanding of the meaning of death, and are more fearful of death and more likely to overestimate the risk of death. These individuals will have a stronger emotional impact when conveying messages about the meaning of death to children and adolescents. It is because people fear death that they try to avoid the dangers or risks that may lead to death. If the risk of death is avoided rationally or reasonably, at best, one is timid. However, if the risk of death is avoided irrationally, one may do one hundred percent of one’s best to prevent one in ten thousand risks, thus becoming a primary form of compulsive symptoms with pathological significance. Generally, this compulsion associated with the fear of death is initially due to the fear of death and some situations closely related to death such as hospital mortuaries, funeral homes, and funerals, and may later develop into more similar situations such as wreath stores, hospital emergency departments, etc., and become a typical compulsion with pathological significance. However, more common compulsive symptoms are not directly related to the death outcome, such as fear of contamination with potentially toxic or harmful objects or substances, avoiding the possibility of contamination as much as possible on the one hand, and taking appropriate “cleaning” measures immediately when contamination occurs on the other. In some cases, after taking a bus, patients worry about their clothes being contaminated by disease-causing substances on others, so they change their outer clothes and take a long bath immediately after getting off the bus and going home, trying to wash all parts of the body that may be contaminated. They also wash each item of clothing carefully and even discard clothing that they think is badly soiled. Other obsessive-compulsive symptoms are not substantially related to death, but the patient establishes a peculiar association with “self-righteous” logic and then avoids the risk. For example, a patient may fear that the placement of certain objects may violate a “taboo” and lead to a catastrophic outcome that the patient also “thinks” he or she has determined, so the objects that violate the “rule” must be placed in accordance with the “rule”. Therefore, it is necessary to place the objects that are against the “rules” according to their “self-righteous” rules. Thus, it can be seen that the process of forming obsessive-compulsive symptoms is more or less associated with the fear of death. In addition, there is a category of “obsessive-compulsive spectrum disorders” or “obsessive-compulsive disorder-related disorders” in the psychiatric disorders unit, and in addition to the similarities that can be found in the professional classification of these disorders, the clinical phenomenology of these symptoms can also be seen They are more or less associated with the fear of death. Examples include hypochondriasis, somatoform disorders, and depersonalization disorders. Hypochondriasis is one of the most closely related obsessive-compulsive spectrum disorders to the fear of death. Patients often perceive themselves as suffering from a fatal disease because of a “strange feeling” in a body part or organ, followed by a great fear and worry, and then go to a professional or hospital for consultation. Repeated medical examinations do not eliminate the suspicion and related anxiety symptoms. Patients with personality disintegration disorder also experience anxiety because they suddenly experience a different relationship with the objective world, and then repeatedly experience and verify this abnormal feeling under the influence of anxiety, and finally decide that their relationship with the objective world has changed abnormally, and suffer from this. It is also from the above relationship between the psychological background associated with the fear of death and the formation of obsessive-compulsive symptoms that we recognize that it is possible to reduce and improve the severity of OCD by changing the fear of death and anxiety. Cognitive-behavioral therapy, often used by psychiatrists in their clinical work, sometimes works by altering the patient’s irrational perception of the relationship between his or her obsessive-compulsive symptoms and the outcome of death.