[Les demoiselles de Rochefort, or a clinical illustration of madness in pairs]. / Les demoiselles de Rochefort, ou une illustration clinique de folie à deux.

Although folie à deux is a confidential entity that has disappeared from psychiatric textbooks and is disguised in current international classifications of mental disorders, which tend to obscure the fundamental notion of the dyad, recent case reports highlight the topicality of the disorder. The richness of the clinical encounter with twin sisters, presenting a common delusion of parasitic infestation, may prompt us to question the disorder differently, guided in particular by ancient writings and the analytic compass.

Coexistence of folie communiquée and folie simultanée.

Objective. The authors report a case during which they observed serious subtypes of induced delusional psychosis (folie communiquée and folie simultanée) without any common genetic background or premorbid psychosis in the case of the secondary patient. Method. The clinical phenomenology of the case is described. Results. Mild intellectual disability and environmental-psychological factors (social isolation and the symbiotic-like interpersonal relatedness) play an essential aetiological role in the case of the secondary recipient patient. Conclusion. The authors emphasize the importance of subclassification of induced delusional psychosis for further aetiological and clinical research.