The nosological significance of Folie à Deux: a review of the literature

BACKGROUND: Folie à Deux is a rare syndrome that has attracted much clinical attention. There is increasing doubt over the essence of the condition and the validity of the original description, such that it remains an elusive entity difficult to define. METHOD: We conducted a systematic review of the literature of all cases reporting the phenomenon of Folie à Deux, from the years 1993–2005. RESULTS: 64 cases were identified of which 42 met the inclusion criteria. The diagnoses in the primary and secondary were more heterogeneous than current diagnostic criteria suggest. There exists a high degree of similarity between the primary and secondary in terms of susceptibility to psychiatric illness, family and past psychiatric history, than previously thought. CONCLUSION: Folie à Deux can occur in many situations outside the confines of the current classification systems and is not as rare as believed, and should alert the clinician to unrecognized psychiatric problems in the secondary

Delírio de infestação parasitária e folie à deux: relato de caso Delusional parasitic and folie à deux: case report

Quadros de transtorno psiquiátrico induzido (folie à deux) são raros. Porém, sua prevalência pode ser de 5-25% nos casos de delírio de infestação parasitária. Relatamos o caso de uma paciente de 62 anos de idade com sintomas psicóticos que, há cerca de 15 anos, está vivendo com sua irmã mais nova. Como a paciente não estava mais apresentando sintomas, sua irmã decidiu não administrar-lhe mais antipsicótico. A paciente voltou a apresentar quadro psicótico marcado por delírio de infestação parasitária, acompanhado por alucinações visuais. Sua irmã, que não tinha história de qualquer transtorno psiquiátrico prévio, passou a acreditar que realmente a paciente estava infestada e que ela mesma fora contaminada. Esse relato de caso objetiva discutir a associação existente entre folie à deux e delírio de infestação parasitária.<br>Shared psychiatric disorder (folie à deux) is a rare condition. But its prevalence can be 5-25% in patients with delusional parasitic infestation. We report the a case of a 62 years-old female with psychotic symptoms. For 15 years, she has lived with her younger sister. Since the patient was well-controled, her sister interrupted her antipsychotic drug administration. So, the patient initiated delusional parasitic infestation accompanied by visual hallucinations. Her sister, who did not have psychiatric history, initiated to believe that the patient was really infested. Moreover, she started to believe that was infested by the patient. This case report aims to discuss the relation between folie à deux and delusional parasitic infestation