The place of opioid system in anorexia nervosa (AN) physiopathology is still unclear. Conflicting results were published on cerebral spinal fluid or peripheral levels in anorexia nervosa. However, no data have been reported on opioid cerebral activity. Diprenorphine is a ligand with non-selective binding to opiate receptors µ, κ and δ capable to assess the interaction between endogenous opioids and their receptors.

Inclusion Criteria:

• AN patients DSM IV criteria including amenorrhea BMI < 17.5 kg/m² and abnormal nutritional markers Group 1 (N=15) : long period of / recurrent weight loss (> 2 yrs) Group 2 (N=15) : recent weight loss (6 to 12 months)
• Recovered AN patients History of AN Weight recovery and BMI > 18.5 kg/m², stable for at least 12 months Normal nutritional markers Group 1 (N=15) : menses recovery after bodyweight stabilization Group 2 (N=15) : long persistence of amenorrhea (> 12 months) despite weight recovery
• Healthy volunteers (N=15) BMI between 18.5 and 25 kg/m², normal nutritional markers, absence of psychiatric or organic pathology
• For all subjects Women 18-35 yrs Written and sign consent Affiliation to health insurance

Exclusion Criteria:

• History of heart failure
• Psychotropic treatment , antiepileptics
• Ongoing or suspected pregnancy, positive beta HCG test before brain imaging
• Intense physical activity
• Constrains for MRI (ferromagnetic implants or claustrophobia)
• Refusal to be informed in case of incidentaloma revealed by brain imaging
• Refusal for written consent