[Folie á deux between two unrelated individuals]

Folie à deux is a rare condition characterized by transmission of delusions from a primary patient to another individual, usually a blood relative or spouse, while living in relative isolation. We report a case of folie à deux, which resembled folie communiquée, in a 37-year-old man that acquired it from an older woman (primary patient). Although not related by blood, the patient was emotionally very close to the woman and they shared common features, including grandiose delusions about the supernatural powers of the primary patient and persecutory delusions concerning office colleagues, as the woman had, and then neighbors, fellow villagers, and even family members. Behavioral changes were observed in the secondary patient as he started wearing strange clothing and peculiar ornaments, and neglected his personal hygiene. He also started following the same rituals and routines as the primary patient, and changed his religious practices, which he had followed devoutly since adolescence. He began seeking her opinion concerning almost all decisions he had to make, including personal and professional matters. Yet, unlike the usual clinical picture, they did not live in social isolation; rather, they lived in an apartment in a well-known residential area of the city and he regularly worked at his office until the late stage of illness. Premorbidly, there were no features suggestive of dependency or low intelligence in the secondary case. After separation from the primary case, improvement was observed about 7 weeks after beginning risperidone treatment (6 mg/day).