Aim: Scientific literature is limited on problems related to the psychotherapy of twins, especially eating disorders. This paper discusses the therapeutic difficulties encountered with two anorexic and one bulimic sets of twins.
Method and results: The three case reports show that the symbiotic tendency of twins is a frequent phenomenon, which may be a special resistance against change, and can serve as a factor maintaining the pathological state. In many cases, the parental behaviour strengthens the symbiosis of the twins, instead of helping the individuation.
Conclusion: The integration of individual and family therapeutic interventions is proposed. The separation-individuation process of the twins can be stimulated by individual sessions with each of the twins, or separate sessions during family therapy (i.e., sessions with the parents and with one of the twins). In this case, the best strategy would be to have the individual and family therapies conducted by the same therapist.