Altered neurotransmission (dopamine, serotonin) and neuroendocrine release (leptin, ghrelin, cortisol), aberrant neural structure activation (hyperactivation of the amygdala and hypoactivation of the insula-ventral striatum circuit) and cognitive and behavioural traits shared by anxiety and anorexia nervosa (rigidity, compulsiveness) contribute to these modifications. This evidence concerns the gene LEP and anorexia nervosa.