People know that smoking is a bad behavioral habit, they know that smoking has many dangers and is associated with many diseases, but they do not know that smoking cessation is a disease, and it is exactly a disease attributed to psychiatry. WHO has included tobacco dependence as a disease in the International Classification of Diseases (ICD), recognizing that tobacco is currently the greatest threat to human health. Why is smoking categorized as a psychiatric disease? There are a lot of mysteries here, which are related to the addictive nature of smoking behavior itself. WHO Expert Committee formally defines substance addiction as “a state of cyclical or chronic intoxication caused by the repeated use of a substance,” with the following characteristics: (1) there is an irresistible force compelling people to use the substance and to obtain it by any means necessary; (2) there is an irresistible force compelling people to use the substance and to obtain it by any means necessary. (1) there is an irresistible force that compulsively drives people to use the substance and to obtain it by any means; (2) there is a tendency to increase the dosage; (3) mental dependence on the effects of the substance and, in general, physical dependence; and (4) it is harmful to both the individual and the society. The so-called physical dependence, also known as physiological dependence, is the repeated use of substances with dependence characteristics, and once the drug is stopped, a series of characteristic and unbearable symptoms and signs will occur. The symptoms that occur after a smoker quits smoking, such as restlessness, irritability, anxiety, depressed mood, lack of concentration, insomnia, decreased heart rate, increased appetite, etc., are all withdrawal symptoms after stopping smoking. The so-called mental dependence, also known as psychological dependence, commonly known as “addiction”, manifested as a strong craving for drugs. After using the drug, there is a feeling of pleasure and relaxation, which can satisfy the psychological needs, and after stopping the drug, there will be unbearable pain and suffering, so you have to continue to use the drug. Nicotine contained in tobacco is the main addictive substance, and nicotine dependence has all the characteristics of drug addiction, so smoking is categorized as a psychiatric disease. Currently, tobacco dependence is a clearly defined psychoneurological disorder. Repeated intake of nicotine from tobacco causes changes in the neural pathways of the brain, resulting in a strong desire to smoke when quitting, which can weaken or even destroy the determination to quit. Tobacco dependence is a chronic, highly relapsing disease. Only a minority of smokers quit completely the first time they quit, and most smokers experience relapse after quitting, requiring multiple attempts to quit. Currently, tobacco dependence is not given enough attention, especially in terms of treatment, and smoking cessation clinics in general hospitals are often virtually non-existent. Due to the lack of psychiatrists, smoking cessation doctors are often respiratory or cardiovascular doctors, resulting in low treatment rates and poor outcomes for smoking cessation.