The Capgras syndrome in paranoid schizophrenia.

Capgras syndrome is characterized by a delusion of impostors who are thought to be physically similar but psychologically distinct from the misidentified person. This syndrome is generally thought to be relatively rare. Most of our knowledge about Capgras syndrome derives from single case studies and small series of cases usually from diagnostically heterogeneous groups. In this article, a series of 31 patients suffering from both paranoid schizophrenia and Capgras syndrome is described. Issues pertaining to the phenomenology of Capgras syndrome, the possible relation between Capgras syndrome and other delusional misidentification syndromes, and a neurobiological hypothesis aimed at explaining Capgras syndrome are discussed.