Evaluation of Brain Opioid Receptor Activity in Anorexia Nervosa : a PET [11C]Diprenorphine Study

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