A 60-year-old woman with moderate Alzheimer dementia becomes convinced that her daughter living with her is an impostor who looks identical to her real daughter. She treats the impostor politely but keeps searching for her actual daughter. The delusion is stable and she functions normally otherwise. Which phenomenon best describes this presentation?
- A Fregoli delusion
- B Cotard delusion
- C Capgras delusion ✓
- D De Clerambault syndrome
Correct answer: C. Capgras delusion
Explanation
Capgras delusion is the fixed belief that a familiar person, usually a close relative, has been replaced by an identical-looking impostor. It reflects disconnection between facial recognition and the autonomic emotional response to familiar faces. Fregoli is the opposite error, a stranger believed to be a familiar person in disguise. Cotard involves nihilistic beliefs about being dead, and De Clerambault is erotomania, the delusion of being loved by another.
Reference: Kaplan and Sadock's Synopsis of Psychiatry, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.