Shared delusions of doubles.

This is the first report of two partners in a folie à deux situation manifesting identical Capgras delusions. It is postulated that the Capgras syndrome developed as a result of interaction between a dominant patient with primarily paranoid psychopathology and a submissive one with primarily organic dysfunction. The submissive "neuro-organic" partner experienced a non-delusional misidentification that acquired a delusional component and developed into the Capgras syndrome as a result of elaboration by the dominant paranoid partner, who subsequently "imposed" the Capgras delusion on the submissive partner. The submissive patient, and, to a lesser extent the dominant patient, had evidence of organic cerebral dysfunction.