While there is broad knowledge on the disruption of appetite regulation, neurocognitive deficits in AN patients, the impact of cortisol on neurocognitive performances in patients with AN and the effects of estrogen on neurocognitive features in healthy subjects, up to now, no study has implemented estrogen replacement in AN patients, in order to examine ist effects upon AN-associated psychopathology, neurocognition and peptides regulating appetite. Thus, this is the first study of its kind.