The Fregoli Delusion: A Disorder of Person Identification and Tracking

Abstract

Fregoli delusion is the mistaken belief that some person currently present in the deluded person's environment (typically a stranger) is a familiar person in disguise. The stranger is believed to be psychologically identical to this known person (who is not present) even though the deluded person perceives the physical appearance of the stranger as being different from the known person's typical appearance. To gain a deeper understanding of this contradictory error in the normal system for tracking and identifying known persons, we conducted a detailed survey of all the Fregoli cases reported in the literature since the seminal Courbon and Fail (1927) paper. Our preliminary reading of these cases revealed a notable lack of definitional clarity. So, we first formulated a classification scheme of different person misidentification delusions so as to identify those cases that qualified as instances of Fregoli according to the above characterization: the mistaken belief that a known person is present in the environment in a different guise to his or her typical appearance. We identified 38 clear cases of this type and set out to answer a series of questions motivated by current hypotheses about the origin of the Fregoli delusion. We asked whether the patients misidentified particular strangers, made reference to the misidentified known persons using wigs or plastic surgery (or other techniques to disguise their appearance), misidentified many different strangers or only one, showed other symptoms (in particular, other misidentification delusions), and made inferences about the motives of the known persons in disguise. We conclude by discussing the implications of our findings for current hypotheses concerning the origin of the Fregoli delusion.

Psychotic Symptoms in Frontotemporal Dementia

“…BIf they are clearly implausible and not understandable to same-culture peers and do not derive from ordinary life experiences^ [60] Claimed she was a park ranger who saved a girl from a rattle snake by picking it up and kissing it [26] Fregoli's delusion BMistaken belief that some person currently present in the deluded person's environment (typically a stranger) is a familiar person in disguise [ 63] Recognizing strangers as acquaintance, despite lack of any resemblance [59] Hallucinations BPerception-like experiences that occur without an external stimulus…They may occur in any sensory modality^ [60] Visual hallucinations of faces or partial faces talking to patient [11]; Satan voice ordering to harm daughter [8]; pruritus caused by infects and snakes on skin [8] predates knowledge of the C9ORF72 mutation. In our experience, early in the symptom course, patients with DLB may have good insight into the hallucinatory nature of these experiences and do not converse with hallucinatory images of people, or may simply tell them to go away, while some of our patients with FTD have been amused at the visual hallucinations of faces and described carrying on pleasant two-way conversations with the images [11].…”

Tracking a Person Over Time Is Tracking What?

“…The Capgras delusion is the delusion that a person before one, a person whom one knows well and would normally care about, is an impostor. Despite the person before one looking like the familiar person, reacting like the familiar person, expressing full and detailed memories of earlier events in the life of the familiar person—the person is the familiar person, of course—to someone in the throes of the delusion the familiar person is taken to be an impostor (Ellis & Lewis, ; see Langdon, Connaughton, & Colheart, ). (Capgras is usually accompanied by some form of major cognitive impairment such as severe schizophrenia.…”

Explaining Person Identification: An Inquiry Into the Tracking of Human Agents

“…The schematic combines components from Bruce and Young's () model and Langdon et al. 's (; see also Langdon, ) account of the factors determining prosopagnosia (F1), Capgras delusion (F2), and Fregoli delusion (F3) (right‐hand side boxes and gray arrows).…”

“…This difference can account for the fact that participants in laboratory experiments perform face‐recognition tasks better when they have to recognize familiar rather than unfamiliar faces. It also suggests a way to account for some errors in person identification (see also Brook, : Section ; Langdon, Connaughton, & Coltheart, ), such as the difficulty that people experience when they have to recognize unfamiliar faces from images like photographic lineups (Lampinen, Neuschatz, & Cling, ; Young & Bruce, : p. 962).…”