Very early hallucinatory experiences: a school-based study.

BACKGROUND: The prevalence and clinical significance of hallucinatory experiences among children below 7 years of age remain unknown. We aimed to determine the independent influences of sensory deficits, the presence of an imaginary companion and metacognition on hallucinatory experiences. We assumed that hallucinatory experiences were associated with (a) sensory deficits, (b) the presence of an imaginary companion (IC) and (c) metacognition defaults (i.e. first- and second-order theory of mind default).

METHODS: All children in the third year of preschool from a region of Northern France underwent medical screening. We compared the prevalence rates of visual, auditory and audio-visual hallucinatory experiences based on (a) the presence of visual or auditory deficits, (b) the actual presence of an IC and (c) metacognition. The analyses were adjusted for age.

RESULTS: A total of 1,087 children aged between 5 and 7 years were included. The prevalence rates of auditory, visual and audio-visual hallucinatory experiences were 15.8%, 12.5% and 5.8%, respectively. The prevalences of different types of hallucinatory experiences were not significantly different according to sensory deficit. The prevalences of all types of hallucinatory experiences were significantly higher among children with an IC and among children with metacognition defaults.

CONCLUSIONS: The association between hallucinatory experiences and sensory deficits might concern only long-lasting deficits. The association with the presence of an IC confirms experimental findings of the likelihood of perceiving words among meaningless auditory stimuli. Relations between hallucinatory experiences and theory of mind need to be addressed in longitudinal studies.