Even though classification systems for psychosomatic disorders are commonly used, the classification is far from being uniform and is frequently associated with diagnostic difficulties. In general, three different types of psychosomatic disorders are distinguished, i.e. hypochondriasis, where no somatic disease is found, somatisation disorders, where the patient does not present with symptoms of psychological distress, and, finally, disorders with both psychological and somatic manifestations. This study discusses the different ways of diagnosing psychosomatic disorders according to the currently available classification systems, such as the International Statistical Classification of Diseases and Related Health Problems (ICD-10) and the Diagnostic and Statistical Manual of Mental Disorders (DSM) by the American Psychiatric Association. Two versions of the latter, namely DSM-IV, which lists somatoform disorders/somatic symptom disorder, and DSM-5, which names the somatic symptom and related disorders instead, have been compared. Other classifications currently in use in Europe and the USA have also been discussed, accounting for entities such as medically unexplained symptoms, bodily distress syndrome and psychological factors affecting other medical conditions. Also, the Diagnostic Criteria for Psychosomatic Research have been presented, encompassing health anxiety, disease phobia, thanatophobia, illness denial, functional somatic symptoms secondary to a psychiatric disorder, persistent somatisation, conversion symptoms, anniversary reaction, irritable mood, type A behaviour, demoralisation and alexythymia.

psychosomatic disorders, classification, medically unexplained symptoms, Diagnostic Criteria for Psychosomatic Research