Capgras delusion in the elderly: The evidence for a possible organic origin

We report the case of a 77‐year‐old right‐handed woman with early dementia of the Alzheimer type who developed the paranoid delusion that her husband had been replaced by an imposter (Capgras phenomenon). Her CT scan showed mild generalized cortical atrophy of the parieto‐occipital cortex. We reviewed the cases of 45 patients over 60 years who showed a Capgras delusion. Twenty‐five suffered from dementia or other chronic organic mental disorders, 20 were paranoid, 14 were at least moderatley depressed and 12 disorientated. CT scans (reported in 17 cases) showed global cerebral atrophy in 12 patients. Right hemisphere infarcts have been described in two elderly patients with Capgras delusions. Focal brain atrophy in Alzheimer type dementia has hitherto not been reported in association with this delusional symptom. We conclude from these observations that marked cerebral lesions and specific neuropsychological deficits are not required for the development of the Capgras phenomenon, which can occur in various functional or organic psychosis of old age.