Delusional misidentification syndromes are a group of phenomena in which patients

incorrectly identify people or objects, or parts of the own body, with the delusional belief that these were replaced or changed.

There are different subtypes, however, most authors distinguish them in Capgras Syndrome, Fregoli intermetamorphosis and Double Subjective Syndrome.

Review these syndromes, addressing some of the neuropsychiatric syndromes related, the various etiological theories of these syndromes, as well as recent neuroanatomical/ neurophysiological data.

Literature review on the subject

Delusional misidentification syndromes have been described in association with other psychiatric disorders in about 60-75% of cases; 25-40% of cases identifies an organic etiology.

Neurophysiological and neuroanatomical data support the hypothesis that these syndromes are related to damage or dysfunction of the right hemisphere level.

Neuropsychological theories have emerged over time: changes at the level offacial recognition, neuronal damage interrupting circuits which mediate information among the face recognition areas located in the temporal cortex and amygdala, and more recently, changes on the neuropsychological evaluation of the belief system.

Several etiological theories have been proposed and the evolution of models has followed the functional / organic dichotomy, with particular focus on the Capgras syndrome. Possibly they have been undiagnosed over time. Emphasis should be given to the central importance of neuroanatomical and neuroimaging data to the growing understanding of these syndromes. Despite the current knowledge, they remain real challenges, both from a clinical perspective, whether for research.