The delusional misidentification syndromes are characterized by a belief in duplicates and replacements. They can be classified as forms of reduplication expressed in the modalities of person, place, time and event, objects, parts of the body and the self. Common features are selectivity, coexistence of forms, intact recognition and faulty identification, depersonalization, and symbolic representation of the patient's feelings, experiences and problems. A neural substrate of altered connectivity of multimodal cortical association areas and paralimbic and limbic structures resulting in a cognitive-perceptual-affective dissonance is suggested.