Visual perception during mirror gazing at one’s own face in schizophrenia

Background: In normal observers gazing at one’s own face in the mirror for some minutes, at a low illumination level, triggers the perception of strange faces, a new perceptual illusion that has been named 'strange-face in the mirror'. Subjects see distortions of their own faces, but often they see monsters, archetypical faces, faces of dead relatives, and of animals. Methods: We designed this study to primarily compare strange-face apparitions in response to mirror gazing in patients with schizophrenia and healthy controls. The study included 16 patients with schizophrenia and 21 healthy controls. In this paper we administered a 7 minute mirror gazing test (MGT). Before the mirror gazing session, all subjects underwent assessment with the Cardiff Anomalous Perception Scale (CAPS). When the 7 minutes MGT ended, the experimenter assessed patients and controls with a specifically designed questionnaire and interviewed them, asking them to describe strange-face perceptions. Results: Apparitions of strange-faces in the mirror were significantly more intense in schizophrenic patients than in controls. All the following variables were higher in patients than in healthy controls: frequency (p < .005) and cumulative duration of apparitions (p < .009), number and types of strange-faces (p < .002), self-evaluation scores on Likert-type scales of apparition strength (p < .03) and of reality of apparitions (p < .001). In schizophrenic patients, these Likert-type scales showed correlations (p < .05) with CAPS total scores. Conclusions: These results suggest that the increase of strange-face apparitions in schizophrenia can be produced by ego dysfunction, by body dysmorphic disorder and by misattribution of self-agency. MGT may help in completing the standard assessment of patients with schizophrenia, independently of hallucinatory psychopathology.