Anger and aggressive behaviours, especially those self-directed, are frequent in subjects suffering from anorexia nervosa and bulimia nervosa. They increase the complexity of the clinical features, change the prognosis and cause a more difficult management of these disorders. In order to elucidate the complex relationships between eating disorders, anger and aggressiveness, the history of traumatic experiences, the prevalence of dissociative, obsessive, impulsive and compulsive symptoms, as well as the role of severe personality disorders in subjects suffering from anorexia nervosa, bulimia nervosa and self-injurious behaviours are considered. In the final section of this paper, a model exploring such a relationship in the light of the undefined sense of self is described.