The paper reviewed here is 'The Delusional Misidentification Syndromes: Strange, Fascinating and Instructive' by Christodolou and colleagues. This is a brief overview of the Delusional Misidentification Syndromes (DMS), a collection of syndromes in which the person holds delusional beliefs about the identify of another person, people or object(s). George Christodoulou has significant experience in this area having authored an article on this as far back as 1978 in which he first described and named the syndrome of subjective doubles. The collective familiarity of the authors with the DMS's is demonstrated by their extensive references to the occurrence of the
dms in mythology and literature.
The four DMS's are described as Capgras Syndrome (in which familiar people are believed to have been replaced by doubles), Fregoli Syndrome (in which a stranger is recognised instead as a familiar person), Intermetamorphosis Syndrome (in which the familiar person and the other person have the same psychological and physical identity and can swap places) and the Syndrome of Subjective Doubles (in which the person believes that other people physically transform into themselves). The authors then cover a number of explanatory models for the DMS's including agnosia of identification secondary to mismatching of sensory input and memories, defence mechanisms (e.g. projection and splitting), 'regression to archaic modes of thought', dysfunction in the right cerebral hemisphere (as well as a similarity to the reduplicative phenomenon), Bruce and Young's adaptation to a face-processing model, Young's interactionist model and Coltheart's two-stage model.
