Somatization disorder is one of the more common subtypes of somatoform disorders. It is a psychiatric disorder with multiple symptoms that can affect multiple systems. Somatization disorder has had many names and a complex history of research. 4000 years ago the ancient Egyptians first described the syndrome and called it “hysteria”. They believed that the disorder originated from the natural displacement of the uterus and attempted to treat the disorder by dragging the “wandering uterus” back to its original position. In 1859, Briquet observed 430 patients in a Paris hospital with a variety of physical symptoms and called them “hysterical”, publishing a series of important papers between 1951 and 953 that established the idea that hysteria involved multiple systems. In his monograph, he further defined hysteria as a variety of dramatic and excessive somatic discomfort in the absence of organic pathology. Psychologists, represented by Freud, believed that ego-defense mechanisms play an important role in the formation of hysterical conversion symptoms, through which “psychic energy” is converted into somatic symptoms. Subsequently, Steke1 introduced the concept of somatization for the first time and considered it equivalent to Freud’s concept of conversion. The etiological mechanisms of somatization disorders are uncertain, and different studies have explored them from biological, psychological, and sociological perspectives. I. Genetic factors Somatization disorder is characterized by familial aggregation. Studies have shown that about 20070 of female one relatives of patients meet the diagnostic criteria for somatization disorder. The family aggregation of somatization disorder can be influenced by genetic, environmental factors or both together. Foster care studies have found that females who were placed in foster care before age 3 and whose foster parents had alcohol or antisocial problems were at a 5-fold increased risk of developing somatization disorder. The risk of somatization disorder in foster children changed with the social status of the foster parents. Early “hysterical” information processing theories suggested that the processing of information in the patient’s brain was defective, leading to many clinical symptoms, and that this defect may be the basis for the somatic disorder patients and their biological relatives’ somatic discomfort, unspecified mental status and pathological redundancy, and some social, interpersonal, and occupational functioning. impairment, etc. Neuropsychological findings suggest deficits in attention and memory function in patients with somatization disorders. Functional neuroimaging studies further revealed some characteristics of somatization disorder patients, such as bilateral frontal lobe symmetry deficits, more severe dysfunction in the dominant hemisphere in patients with depressive disorders (also seen in patients with antisocial personality disorder), and more severe dysfunction in the anterior part of the nondominant hemisphere than in the posterior part. Auditory evoked potential examination also confirms that patients with somatization disorder are mostly associated with abnormal cortical function. Psychosocial factors Increased somatic complaints are associated with living alone, receiving less stimulation from the outside environment, depression and anxiety. Personality traits, neuroticism and introversion are also associated with the occurrence of somatization disorder. The association between somatization disorder and personality disorders has been recognized earlier; Hudziak et al. and Cloninger et al. found similarities and even overlap between somatization disorder and borderline personality disorder, with male relatives of female somatization disorder patients at increased risk for antisocial personality disorder and alcohol abuse, while men had different clinical symptoms and no clustering among either their male or female relatives. Overall, these findings suggest a common etiology and an association between somatization disorder and antisocial personality disorder in women, whereas somatization disorder in men is more commonly associated with anxiety disorders. Classical psychodynamic theory suggests that somatization disorder is the replacement of repressed noninstinctive impulses with somatic symptoms. Patients express emotional conflict through somatic symptoms to deal with stress and alleviate psychological conflict. Researchers have also proposed other theories to explain the symptomatology of somatization disorder patients, including the “hysterical” information processing theory and the social model theory of somatization disorder. The social model theory suggests that patients somatize symptoms as a way of expressing emotions (e.g., pain) within the family and expect to seek support and attention from core family members (e.g., a young woman who presents with persistent abdominal pain, thus preventing her parents from going away for the weekend). Somatization disorder is characterized by the presence of one or more somatic symptoms, many of which cannot be medically explained. The most common are gastrointestinal symptoms (e.g., pain, eructation, regurgitation, vomiting, constipation or diarrhea), headache, pain in other areas, abnormal skin sensations (e.g., itching, burning, tingling, numbness, aching, etc.), and complaints of sexual function and menstruation are also common. The manifestations are varied, the symptoms are recurrent, involving multiple systems, and are mostly accompanied by clinical anxiety or depression. Common symptoms include: 1. gastrointestinal symptoms nausea, vomiting, abdominal pain, diarrhea, constipation. 2. pain Chest pain, back pain, joint pain, urination pain. 3.Transformation symptoms Difficulty in swallowing, loss of voice, blindness, deafness. 4.Pseudoneurological symptoms Epileptic-like seizures or convulsions, muscle paralysis, abnormal skin sensation. 5.Reproductive system symptoms Dysmenorrhea, irregular menstruation, excessive menstrual flow. 6. Respiratory and circulatory system Chest tightness, shortness of breath, palpitations, dizziness. In the International Classification of Diseases (ICD-IO), the main characteristic of somatization disorder is a variety of recurrent and frequently changing somatic symptoms that last for at least 2 years. The majority of patients have had a history of primary or specialized health care visits and have had multiple negative test results or unsuccessful exploratory procedures that support the lack of association with somatic disorders. Somatization disorder is a purely somatic manifestation of personal or social repression. The course is chronic and fluctuating, and is often accompanied by social, interpersonal and family behavioral disturbances. Most patients with somatization disorder are accustomed to immersing themselves in the experience of somatic symptoms and are reluctant to accept the link between somatic symptoms and psychological factors; symptoms rarely resolve completely, and it is not uncommon to see a combination of substance dependence or abuse. Treating these patients clinically can be challenging. A diagnosis of somatization disorder requires a history of somatic disorders that began before age 30 and lasted for many years. The requirements for positive symptoms are similar to the Feighner criteria. In general, invasive testing should not be performed or withheld when objective indications are lacking or unclear. The clinician does not need to search for evidence to confirm whether the symptoms are real or not; the patient’s complaints are sufficient to determine the presence or absence of symptoms. If a symptom cannot be explained by “somatic dysfunction or impairment” or “cannot be explained by the side effects of drugs or alcohol,” then it can be judged as unexplained by current medical knowledge: 1. A variety of somatic symptoms The complaints are of at least two years’ duration and cannot be explained by any detectable somatic disorder (the presence of any somatic disorder cannot explain the severity, range, variability, and persistence of the somatic complaints and diminished social functioning). Even though some symptoms are caused by autonomic nervous system arousal, if these symptoms are not prolonged or distressing, they are not somatization disorders. 2. Symptoms can cause severe distress and lead to multiple (three or more) visits to the doctor or various tests. 3. Repeated refusal to accept the physician’s assurance that the symptoms do not cause the corresponding somatic disorder. 4. Must be accompanied by six or more of the symptoms listed below and the symptom occurrence involves at least two systems.