BackgroundNon-organic lesions or diseases of unknown origin are sometimes misdiagnosed as “psychogenic” disorders or “psychosomatic” diseases. For the quality of life and safety of patients, recent attention has focused on diagnostic error. The aim of this study was to clarify the factors that affected misdiagnoses in psychosomatic medicine by examining typical cases and to explore strategies that reduce diagnostic errors.Case presentationThe study period was from January 2001 to August 2017. The data of patients who had visited the Department of Psychosomatic Medicine, Kindai University Hospital and its branches, Sakai Hospital and Nihonbashi Clinic, were collected. All patients were aged 16 years or over. Multiple factors, such as age, sex, presenting symptoms, initial diagnosis, final diagnosis, sources of re-diagnosis and types of diagnostic errors were retrospectively analyzed from the medical charts of 20 patients. Among them, four typical cases can be described as follows. Case 1; a 79-year-old woman, initially diagnosed with psychogenic vomiting due to depression that was changed to gastric torsion as the final diagnosis. Case 2; a 24-year-old man, diagnosed with an eating disorder that was later changed to esophageal achalasia. Case 10; a 60-year-old woman’s diagnosis changed from conversion disorder to localized muscle atrophy. Case 19; a 68-year-old man, appetite loss from depression due to cancer changed to secondary adrenal insufficiency, isolated ACTH deficiency (IAD).ConclusionThis study showed that multiple factors related to misdiagnoses were combined and had a mutual influence. However, they can be summarized into two important clinical observations, diagnostic system-related problems and provider issues. Provider issues contain mainly cognitive biases such as Anchoring, Availability, Confirmation bias, Delayed diagnosis, and Representativeness. In order to avoid diagnostic errors, both a diagnostic system approach and the reduction of cognitive biases are needed. Psychosomatic medicine doctors should pay more attention to physical symptoms and systemic examination and can play an important role in accepting a perception of patients based on a good, non prejudicial patient/physician relationship.

The psychological problems of non-Japanese people are becoming more outstanding, in accordance with the increase of foreign nationals in Japan. Five illustrative cases of English-speaking patients were analyzed, from the viewpoint of psychosomatic medicine. The most common psychiatric disorders were adjustment disorders, because of the cultural differences and language barriers.