The Capgras and Cotard delusions.

We explore the relation between the Capgras delusion (the belief that your relatives have been replaced by impostors) and the Cotard delusion (the delusional belief that you have died). At first sight, these delusions would seem to have little to do with each other, except that they both involve bizarre claims about existence (for self or others). On closer examination, however, there are other parallels. Here, we summarise similarities in associated impairments of face perception, and argue that both delusions reflect an interaction of impairments at two levels. One set of contributory factors involves perceptual impairment, or anomalous perceptual experience. The other factors lead to an incorrect interpretation of this, for which we offer an explanation in terms of attribution theory. Although the Capgras and Cotard delusions are phenomenally distinct, they may therefore represent attempts to make sense of fundamentally similar experiences.