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Anorexia nervosa is an eating disorder whose symptomatology induces a modification of the intestinal microbiota. To date, studies have shown variable profiles without linking them to metabolic and neuropsychological energy phenotyping. This intestinal dysbiosis could be involved in the maintenance of the disorders. Bidirectional communication channels exist between the microbiota, the intestine and the brain. Anomalies in these pathways could explain the impact of the microbiota on the pathophysiology of anorexia nervosa. Therapeutic interventions would then be possible to restore the microbiota in anorexia nervosa and influence the treatment of this disease. This study aims to explore the hypothesis of disruption of the microbiota-intestinal-brain axis transversely and measuring the intestinal microbiota, urinary metabolome, biological factors nutritional, immunological and physiological plasma plasma of the intestine, and finally, the psychological dimensions characteristic of 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)

only female

• anorexia nervosa with and without hunger
• constitutional leanness
• control subjects