Psychiatric institutions often play a central role in the treatment of eating disorders because of their large number of facilities. However, currently patients with eating disorders are overly concentrated in a few specialized medical institutions for eating disorders. Importantly, psychiatric institutions should collaborate with each other to provide treatment tailored to the patient's condition, but in many medical areas, progress in the development of medical collaboration for eating disorders is lacking. Therefore, we have developed the "Guideline for collaboration among psychiatric institutions for the treatment of eating disorders" as part of a research project funded by the Japan Agency for Medical Research and Development (AMED) from the fiscal year 2009. In preparing this guideline, we first conducted a primary survey of general hospital psychiatry, psychiatric hospitals, and psychiatric clinics to clarify the current status and problems of cooperation in the treatment of eating disorders in psychiatric institutions. From this survey, the following important clinical issues were identified: the basic concept of medical cooperation, criteria for allocating medical institutions, and tools for sharing information to facilitate medical cooperation. This guideline was completed by collecting the opinions of psychiatrists who provide specialized treatment.
 The guideline suggests the criteria for medical institutions that should respond to the degree of underweight, and also suggests that transfer to another hospital should be considered according to the weight gain resulting from to inpatient treatment. It also includes a flowchart summarizing the criteria for cooperation, a contact form for patient referral, and a template for a list of medical institutions. However, it is assumed that these criteria will be adjusted in consideration of the regional characteristics and medical systems of each medical area. Based on this guideline, it is expected that local governments will play a central role in establishing a system of medical cooperation that is in line with the actual situation of eating disorder treatment in the region.
 Authors' abstract