Neuropsychiatric characteristics of capgras syndrome in Alzheimer's disease in the CATIE-AD

Introduction: Capgras syndrome (CS) is a recurrent and transient delusional misidentification disorder in which an individual is firmly convinced that a familiar person has been replaced by an identical impostor. The aim of the study was to evaluate neuropsychiatric characteristics of CS in a cohort of patients with Alzheimer’s disease (AD). Methods: 150 participants [84 (56.0%) women, mean age 77.4 ± 7.5 years)] were collected within the Clinical Antipsychotic Trials of Intervention Effectiveness-Alzheimer disease (CATIE-AD). According to the Neuropsychiatric Inventory, patients were classified into Capgras+ and Capgras−. Results: Fifty-five (36.7%) AD patients were Capgras+. CS was strongly associated with other misidentification syndromes including phantom boarder (p < 0.001) and misidentification of places (p < 0.001). Moreover, Capgras+ were presented more frequently with agitation (p = 0.036), depressive (p = 0.018) and anxious (p = 0.004) symptoms, and aberrant motor behaviours (p = 0.020). Conclusions: According to our findings, CS was not an ‘isolated’ phenomenon but rather a complex neuropsychiatric syndrome frequently associated with other misidentification syndromes and specific behavioural disturbances.