Folie à plusieurs: forensic cases from nineteenth-century Ireland

Abstract

Folie à plusieurs is a syndrome in which two or more individuals share symptoms (e.g., delusions). This paper uses archival material to present and discuss forensic psychiatric cases of folie à plusieurs from nineteenth-century Ireland. The cases of three brothers who all `became insane at the same time' and killed another brother illustrate: the role of organic factors in folie à plusieurs; the use of `moral management' strategies; and the problem of tuberculosis in asylums. The case of one woman whose family `all became insane at once' and killed one of her sons illustrates: the importance of identifying the `primary' patient; the difficulties experienced by `secondary' cases; and the limited therapeutic progress achieved in nineteenth-century asylums. While further historical study is required to explain the emergence of the concept of folie à plusieurs in the late nineteenth century, it is clear that, over one hundred years since the term came to prominence, `communicated insanity' still presents substantive diagnostic, clinical and ethical challenges to mental health and judicial services.