OCD used to be considered a rare mental illness, but recent epidemiological studies have found that the prevalence of OCD is 2 to 3%, which means that 2 to 3 out of 100 people suffer from OCD. The reason why it was thought to be rare in the past is partly due to the lack of awareness of OCD and partly because OCD patients recognize the absurdity of their thoughts and the weirdness of their behavior, so they try to control themselves from acting out in public. They also fear that they will be diagnosed as mentally ill if they go to the doctor, so OCD is very “hidden” in its early stages. So what kind of mental illness is OCD? OCD is an anxiety disorder. Patients with OCD have a constant stream of disturbing thoughts in their heads that force them to do things repeatedly to relieve their anxiety. For example, many OCD patients are always worried about whether the doors, windows, drawers, gas switches, etc. are closed and have to check them many times before they feel at ease. Some patients are overly worried about being contaminated by bacteria, viruses or dirty things, and are afraid to touch normal things. If they touch something they think is dirty, they have to wash their hands repeatedly and for a long time; some patients must do things according to a fixed procedure that cannot be broken or interfered with, such as their shoes to be placed absolutely neatly before going to bed, clothes off in what place, and so on, if interfered with, they must start from scratch, which will consume a lot of time. Some patients have to keep counting when doing certain things, and must count until they are satisfied or lucky with the number. A few patients will only have compulsive thoughts, but not compulsive behaviors. For example, some meaningless words, sentences or thoughts, or disturbing images, etc., repeatedly appear in the mind and the patient cannot get rid of them. As the disease progresses, the patient will spend more and more time on obsessive thoughts or behaviors, so much so that it seriously hinders the patient’s life, work and study. Does having the above symptoms necessarily mean that the person has OCD? Not necessarily, because normal people also have some obsessive-compulsive phenomena and other mental illnesses can be accompanied by obsessive-compulsive symptoms. Therefore, if you feel similar to the above mentioned manifestations, it is best to see a professional psychiatrist or psychologist to discuss your symptoms with him for a clear diagnosis. Many patients are afraid to go to the doctor because they are worried that OCD is a mental illness. In fact, this concern is unnecessary. Because the vast majority of OCD patients can recognize that their thoughts and behaviors are meaningless and problematic, while psychiatric patients are unable to recognize their thoughts and behaviors as abnormal. Therefore OCD is not a mental illness. OCD is treatable, and the most effective treatments for OCD currently include medication and cognitive behavioral therapy. A combination of the two will give better results. Medications that are effective for OCD include selective 5-HT reuptake inhibitors, such as fluoxetine and paroxetine, and the tricyclic group of chlorpromazine. Cognitive-behavioral treatments focus on exposure and response prevention and can be effective in consolidating efficacy and preventing relapse.