Capgras syndrome is a disorder of personal identification characterized by the delusional belief that one or more persons close to the subject have been replaced by physically identical doubles.

To deepen our knowledge of the Capgras syndrome

A case report about a Capgras syndrome.

We report the case of a 46-year-old female patient who was admitted in February 2021 for incoherent speech and behavior disorder against her family members. Three years ago, she started to have hypochondriacal concerns. A week before her admission, she threatened her husband with a knife and she was convinced that her daughters were dead and that they had been replaced by clowns. She had a Capgras delusion with a hallucinatory and interpretative mechanism against her daughters, she reported olfactory and cenesthetic hallucinations. Biological explorations and brain CT were normal. The PANNS scale showed a positive scale of 36, a negative scale of 39, the general psychopathology scale of 53. She had a total score of 30/40 on The Penn emotion recognition test. The patient had difficulty in recognizing low intensity emotions (0 or 1) and 50% of the false responses were for the neutral emotion with responses tending towards anger first and then sadness.

Capgras syndrome remains poorly described in the literature and the hypotheses concerning its origin often oscillate between neuropsychological and psychodynamic. With the recent advances in neuroscience, it would be interesting to deepen its physiopathology in order to place it in a more modern nosological framework.

No significant relationships.

Impairments in social cognition contribute significantly to disability in schizophrenia patients (SzP). Perception of facial expressions is critical for social cognition. Intact perception requires an individual to visually scan a complex dynamic social scene for transiently moving facial expressions that may be relevant for understanding the scene. The relationship of visual scanning for these facial expressions and social cognition remains unknown.

In 39 SzP and 27 healthy controls (HC), we used eye-tracking to examine the relationship between performance on The Awareness of Social Inference Test (TASIT), which tests social cognition using naturalistic video clips of social situations, and visual scanning, measuring each individual's relative to the mean of HC. We then examined the relationship of visual scanning to the specific visual features (motion, contrast, luminance, faces) within the video clips.

TASIT performance was significantly impaired in SzP for trials involving sarcasm (p < 10−5). Visual scanning was significantly more variable in SzP than HC (p < 10−6), and predicted TASIT performance in HC (p = 0.02) but not SzP (p = 0.91), differing significantly between groups (p = 0.04). During the visual scanning, SzP were less likely to be viewing faces (p = 0.0001) and less likely to saccade to facial motion in peripheral vision (p = 0.008).

SzP show highly significant deficits in the use of visual scanning of naturalistic social scenes to inform social cognition. Alterations in visual scanning patterns may originate from impaired processing of facial motion within peripheral vision. Overall, these results highlight the utility of naturalistic stimuli in the study of social cognition deficits in schizophrenia.