Prevalence and dimensionality of hallucination-like experiences in young adults

BACKGROUND: The study of hallucination-like experiences (HLEs) in non-clinical populations is increasingly used to corroborate etiological models of psychosis. This method capitalizes on the absence of confounding factors that typically affect the study of hallucinations in clinical subjects. AIM: To estimate the prevalence of HLEs in young adults; validate the mutidimensionality and explore the correlates of latent HLEs clusters. METHODS: Cross-sectional survey design. The extended 16-item Launay-Slade Hallucination Scale (LSHS-E) and the 12-item General Health Questionnaire (GHQ-12) were administered to 649 Italian college students (males: 47%). Confirmatory factorial analysis was used to test multidimensionality of the LSHS-E. Hierarchical nested, progressively constrained models were used to assess configural, metric and scalar invariance of the LSHS-E. Latent class analysis was used to test the existence of different profiles of responding across the identified hallucination-proneness dimensions. RESULTS: Factor analysis showed that the four-factor model had the best fit. Factors were invariant across demographic variables and levels of psychological distress. Three latent classes were found: a large class with no HLEs (70% of participants), a multisensory HLEs class (18.8%), and a high hallucination-proneness class (11%). Among those reporting high levels of HLEs, approximately half reported scores indicative of considerable psychological distress. CONCLUSIONS: Although HLEs have a relatively high prevalence in the general population, the majority of those experiences happen in isolation and are not associated to psychological distress. Approximately half of those individuals experiencing high levels of HLEs report significant psychological distress. This may be indicative of general risk for mental health conditions rather than specific risk for psychosis.