ABSTRACT
BACKGROUND: Various theories have been proposed concerning the syndrome of Capgras. AIM: To search for a concept that is common to the various theories relating to the aetiology of the syndrome of Capgras. METHODS: We begin by describing a new case of Capgras syndrome that we encountered recently, and thereafter we searched the literature using PubMed and PsycINFO. RESULTS: Various explanatory models converge in that they all assign a central role to a changed affect. A sensation of 'alienation' at a conscious or subconscious level, together with inadequate evaluation of beliefs, seems plausible. All models demonstrate some form of 'splitting' i.e. the separate processing of information in time, anatomy or mental representation. CONCLUSION: Although there is no conclusive evidence to support any one of the hypotheses, the models display striking similarities. They complement each other.