A hundred and fifty years since first described, Anorexia Nervosa continues to problematize scientists regarding its etiology and diagnosis but -primary- its treatment or prevention. The cases of patients characterized as having an "Atypical" Eating Disorder are raised and the present diagnostic criteria are faced with skepticism by many psychiatrists. The etiology of Anorexia Nervosa is considered to be so multifactorial that none of the existing theories (biological, cognitive, systemic and psychodynamic) can satisfactorily explain totally the clinical manifestations of the disorder. Social component seems to play -among others- an important role. Nevertheless, recently there is in process a remarkable effort in order to standardize a clear therapeutic plan totally adjusted in the severity of the clinical features in the course of the disorder. Some treatments seem to be more efficacious than others but generally the results in treating Anorexia Nervosa are not satisfactory.