Hypochondriasis, also known as hypochondriacal neurosis, mainly refers to the persistent preoccupation of patients with this disease who worry or believe that they have one or more serious physical diseases. Patients complain of physical symptoms and repeatedly seek medical treatment. Although repeated medical examinations are negative and the doctor's explanation that there is no evidence of the corresponding disease cannot dispel the patient's concerns, they are often accompanied by anxiety or depression. Suspicion or preoccupation with body deformity also belongs to this disease. This disease is rare. According to the epidemiological survey of neurosis in 12 regions across the country, its total prevalence is only 0.15‰. The psychiatry department of West China University of Medical Sciences found that it accounted for 9.0% of neurosis in a county hospital outpatient survey. In the analysis of 500 consecutive cases in the psychiatric outpatient clinic, only one case was found in neurosis, which is a big difference. According to foreign statistics, this disease accounts for 1% of the total number of inpatients. There is no difference between the two sexes. The age of onset is mostly 40 years old for men and around 50 years old for women. It is not uncommon for the elderly.