Anorexia nervosa (AN) has been linked with pre-morbid disorders, comorbidity, and specific personality traits in between-family case-control studies. However, these findings have not been replicated in within-family studies, and it is not known whether these factors are linked specifically with AN or are shared familial factors. We aimed to compare pre-morbid disorders, comorbidity, and specific personality traits between sister-pairs discordant for AN. Forty-five families with two sisters discordant for AN were retrospectively assessed by interview and questionnaires. The proband with AN had mood disorders and personality disorders (PDs) more frequently than their sister and had lower scores of novelty seeking, self-directedness and cooperativeness, and higher scores of harm avoidance, persistence, self-transcendence and of all EDI-2 scales. In conclusion, major depression, cluster C PDs, persistence, harm avoidance, and self-transcendence appear to be specifically linked to AN and to be European Eating Disorders Review