Capgras Delusion

The Capgras delusion is a delusional misidentification syndrome in which a person becomes convinced that a close friend, spouse, parent, other family member, or even a pet has been secretly replaced by an identical impostor, a belief that can occur in acute, transient or chronic form. The French psychiatrists Joseph Capgras and Jean Reboul-Lachaux first described the condition in 1923, originally naming it l'illusion des sosies, or the illusion of doubles, after studying a woman who believed her own husband had been replaced by a double. Leading explanations for the delusion propose that it results from a genuine disconnection within the brain's face-processing system: one influential account holds that a person's ordinary automatic emotional response to a familiar face becomes damaged while conscious visual recognition of that face remains intact, so a patient consciously recognizes a loved one's face but feels none of the expected emotional familiarity, and resolves that unsettling mismatch by concluding the person must be an impostor; other proposed accounts point to a damaged internal representation of the person's full identity, including personality and emotional significance, or to a disrupted link between episodic memories and their normal emotional weight. The delusion occurs across a range of underlying conditions, most commonly schizophrenia and other psychotic disorders, and also appears with brain injury, dementia with Lewy bodies, and a range of other neurological and metabolic conditions, occurring somewhat more often in women than in men.