title: Prevalence and dimensionality of hallucination-like experiences in young adults.
abstract: 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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Center of Liaison Psychiatry and Psychosomatics, University Hospital, University of Cagliari, Italy; Section on Clinical Psychology, Department of Education, Psychology, Philosophy, University of Cagliari, Italy; Genneruxi Medical Center, Cagliari, Italy. Electronic address: apreti@tin.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Preti
authors.affiliation: Department of Biomolecular Sciences, Service of Biostatistics, University of Urbino, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Sisti
authors.affiliation: Department of Biomolecular Sciences, Service of Biostatistics, University of Urbino, Italy.
authors.forename: Marco Bruno Luigi
authors.initials: MB
authors.lastname: Rocchi
authors.affiliation: Section on Clinical Psychology, Department of Education, Psychology, Philosophy, University of Cagliari, Italy; Unit of Research and development, Parc Sanitari Sant Joan de Déu, Barcelona, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Siddi
authors.affiliation: Department of Psychology, Institute of Psychiatry, King's College London, De Crespigny Park, SE5 8AF, London, UK.
authors.forename: Matteo
authors.initials: M
authors.lastname: Cella
authors.affiliation: Section on Clinical Psychology, Department of Education, Psychology, Philosophy, University of Cagliari, Italy.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Masala
authors.affiliation: Section on Clinical Psychology, Department of Education, Psychology, Philosophy, University of Cagliari, Italy.
authors.forename: Donatella Rita
authors.initials: DR
authors.lastname: Petretto
authors.affiliation: Center of Liaison Psychiatry and Psychosomatics, University Hospital, University of Cagliari, Italy.
authors.forename: Mauro Giovanni
authors.initials: MG
authors.lastname: Carta
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006212:Hallucinations / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011594:Psychometrics; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D013223:Statistics as Topic; D013334:Students / Q000523:psychology / Q000706:statistics & numerical data; D055815:Young Adult