Definition Of DMS

The four DMS's are described as Capgras Syndrome (in which familiar people are believed to have been replaced by doubles), Fregoli Syndrome (in which a stranger is recognised instead as a familiar person), Intermetamorphosis Syndrome (in which the familiar person and the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 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.

The article is succinct and the authors expertly navigate through this esoteric field which spans nearly 100 years. Perhaps a neat unifying theory may not be forthcoming given the considerable variation in phenemonology, comorbidity and sequalae and the field may settle with a number of successful explanatory models with identifiers for their use. Christodoulou and colleagues have written a concise and useful overview of the field which includes some of the most recent models for those interested in the Delusional Misidentification Syndromes.