Hypochondriasis is a subtype of somatoform disorder, classified at the upper level as a neurological disorder, and is characterized by three aspects: 1. Excessive fear of suffering from various somatic diseases, and mostly serious incurable diseases, such as AIDS, rabies, cancer, unknown viral or bacterial infections, and many other diseases. Excessive concern about physical discomfort, physical weakness, pain and many other discomforts are often associated with the feared disease, very fearful, urgent to seek medical attention, do a comprehensive physical examination, the doctor to rule out the feared disease. The patient will be slightly calmed down inside, but will not be well for long and will soon worry again. 2., Patients need to repeatedly seek medical treatment, in order to clarify the diagnosis, often constantly changing doctors or hospitals, seeking all sides of the examination and treatment, but little effect, internal pain, lasting more than six months, to bring significant impact on personal work, life, study. 3. There are often certain psychological factors and life events before the onset of the disease, such as experiencing serious illness or death of family members or friends, experiencing certain disasters or injuries, engaging in certain high-risk occupations or things, etc.