THE LOSS OF FAMILIARITY: A CASE STUDY OF THE COMORBIDITIES OF CAPGRAS AND FREGOLI

This case study describes the coexistence of Capgras and Fregoli-type delusions in a 51-year-old woman. The patient reported that her children were kidnapped and replaced with doubles. She claims that several customers at her shop are her real children. Neuropsychological assessment revealed severe defects in social cognition and an increased number of perseveration responses in the self-directed signaling task. We propose that the latter finding is a measure of the familiarity phenomenon and may be associated with hypofunction in the left retrosplenial region. SPECT-CT confirmed a pattern of hypoperfusion in the retrosplenial, posterior cingulate, and prefrontal cortex.