Abstract

Objective: Patients with Capgras syndrome, a form of reduplicative paramnesia, suffer from the delusional belief that certain persons well known to them have been replaced by seemingly identical impostors, despite contrary evidence. Capgras delusions have been observed in both psychiatric and neurologic patients; however, neuroimaging studies most often reveal diffuse cerebral atrophy and/or bifrontal and right cerebral hemisphere pathology. The purpose of this case study is to expand on the literature of this infrequently occurring disorder presenting in conjunction with a probable dementia vs. late-onset psychosis. Method: This is the case of a 75-year-old married female who presented to her primary care physician with impaired memory along with the unshakable belief that her husband was plotting against her and that her siblings and children were deceased and replaced by exact physical doubles. These symptoms had been present for approximately 6 years with a progressive pattern and a marked decline over the last year. Her physician initially diagnosed a thought disorder and referred her for a neuropsychological assessment to assist in the differential diagnosis of psychosis versus dementia. Results: Neuropsychological testing indicated functional impairment on measures associated with executive, visual spatial, and memory abilities. Findings supported a diagnosis of probable dementia with Capgras delusions, rather than a late-onset psychosis. The diagnosis was subsequently confirmed by combined neuroimaging, neurological, and psychiatric evaluations Conclusion(s): The clinical and neuroradiographic aspects of Capgras delusions are discussed, as is the role of neuropsychological evaluation in differential diagnosis of patients with delusional misidentification.