The masks of identities: who's who? Delusional misidentification syndromes

Delusional misidentification syndromes (DMSs) are complex psychotic phenomena that may be present in a variety of ways within the context of several neurological and psychiatric disorders. Since the first case of Capgras syndrome was described in 1923, various other syndromes have been identified, including Fregoli syndrome, intermetamorphosis, subjective doubles, reduplicative paramnesia, mirrored self, delusional companions, and clonal pluralization of the self. In this article, we review each of the different syndromes in definition and presentation, as well as the field's attempts at classifying them. We then describe their role in forensic psychiatry, particularly in regard to their potential as a marker of a particular subpopulation or of illness severity and their consideration in risk assessments of violence. A review of the literature was conducted for this purpose, and, although it was extended to include publications from over four decades, it revealed a paucity of research on DMSs.