Uncovering Capgras delusion using a large-scale medical records database

Abstract

© The Royal College of Psychiatrists 2017 This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) licence. Background Capgras delusion is scientifically important but most commonly reported as single case studies. Studies analysing large clinical records databases focus on common disorders but none have investigated rare syndromes. Aims Identify cases of Capgras delusion and associated psychopathology, demographics, cognitive function and neuropathology in light of existing models. Method Combined computational data extraction and qualitative classification using 250 000 case records from South London and Maudsley Clinical Record Interactive Search (CRIS) database. Results We identified 84 individuals and extracted diagnosis-matched comparison groups. Capgras was not 'monothematic' in the majority of cases. Most cases involved misidentified family members or close partners but others were misidentified in 25% of cases, contrary to dual-route face recognition models. Neuroimaging provided no evidence for predominantly right hemisphere damage. Individuals were ethnically diverse with a range of psychosis spectrum diagnoses. Conclusions Capgras is more diverse than current models assume. Identification of rare syndromes complements existing 'big data' approaches in psychiatry.