“Tandem anorexia” in dizygotic twin sisters Masha and Dasha

The article describes a unique combination of anorexia nervosa in 15-year-old dizygotic twin sisters, Masha and Dasha, which developed synchronously and proceeded with a similar clinical picture. Within six months from the time they jointly made the decision to change their eating habits and follow a special diet, each of the sisters lost more than 25% of her body weight. However, they each still had an obsessive fear of gaining weight, preoccupation with appearance, dissatisfaction with their figures and volumes of various body parts, and also periodically disrupted their menstrual cycles. The mechanism of the development of eating disorders in each of them was analyzed and it was concluded that the principle of fierce competition between them turned out to be fundamental. The twin sisters constantly compared the results of weight loss, making sure that the other did not achieve better results. This was accompanied by emotional reactions such as resentment, irritation, complacency or gloating. It is concluded that the clinical case of “tandem anorexia” in dizygotic twin sisters Masha and Dasha allows us to confirm the fact that the formation of “pair psychopathology” (in this case, eating disorder) may be associated not so much with genetic factors, but with psychological mechanisms and should be taken into account when choosing a treatment strategy.