Study of the Microbiological Profile of Stool in Patients With Anorexia Nervosa

Inclusion criteria common to all four groups * Patient affiliated or entitled to a social security scheme * Patient who received informed information about the study * Patient does not object to participating in the study Inclusion criteria specific to mental anorexia * BMI between 13 and 17.5 kg/m2 * Diagnostic and Statistical Manual of Mental Disorders IV restrictive anorexia nervosa diagnostic criteria * Evolution of the troubles since less than 1 year. * with feeling of hunger: "hunger" = total score on the 24-hour hunger scale \> 15 and presence of the three prandial peaks (score = 3) * having lost the feeling of hunger: "not hungry" = total score on the 24-hour hunger scale ≤ 5 and absence of the three prandial peaks (score ≤ 2) Inclusion criteria specific to constitutionally thin patients * BMI between 13 and 17.5 kg/m2 * Stable weight for at least 3 months * No eating disorder * No markers of undernutrition Inclusion criteria specific to normal weight subjects * 20 kg/m2 ≤ BMI ≤ 25 kg/m2 * Stable weight for at least 3 months * No eating disorder * No markers of undernutrition Non-inclusion criteria for all subjects : * Antibiotic treatment during the 2 months preceding the sampling. * History of immune system/autoimmune disease: Immune deficiency, Crohn's disease, systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, psoriasis, Behçet's disease, celiac disease, type I diabetes. * History of metabolic pathology: intestinal malabsorptive disease * Medical or surgical history deemed by the investigator to be incompatible with this study. * Severe progressive condition other * Pregnant woman * Majors under guardianship or subjects deprived of their liberty by judicial or administrative decision * Ongoing psychotropic treatment * Progressive diarrhea (Bristol Type V and VI)