Variation of subclinical psychosis across 16 sites in Europe and Brazil: findings from the multi-national EU-GEI study

Giuseppe D'Andrea, Diego Quattrone, Kathryn Malone, Giada Tripoli, Giulia Trotta, Edoardo Spinazzola, Charlotte Gayer-Anderson, Hannah E Jongsma, Lucia Sideli, Simona A Stilo, Caterina La Cascia, Laura Ferraro, Antonio Lasalvia, Sarah Tosato, Andrea Tortelli, Eva Velthorst, Lieuwe de Haan, Pierre-Michel Llorca, Paulo Rossi Menezes, Jose Luis SantosManuel Arrojo, Julio Bobes, Julio Sanjuán, Miguel Bernardo, Celso Arango, James B Kirkbride, Peter B Jones, Bart P Rutten, Jim Van Os, Jean-Paul Selten, Evangelos Vassos, Franck Schürhoff, Andrei Szöke, Baptiste Pignon, Michael O'Donovan, Alexander Richards, Craig Morgan, Marta Di Forti, Ilaria Tarricone*, Robin M Murray

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

BACKGROUND: Incidence of first-episode psychosis (FEP) varies substantially across geographic regions. Phenotypes of subclinical psychosis (SP), such as psychotic-like experiences (PLEs) and schizotypy, present several similarities with psychosis. We aimed to examine whether SP measures varied across different sites and whether this variation was comparable with FEP incidence within the same areas. We further examined contribution of environmental and genetic factors to SP. METHODS: We used data from 1497 controls recruited in 16 different sites across 6 countries. Factor scores for several psychopathological dimensions of schizotypy and PLEs were obtained using multidimensional item response theory models. Variation of these scores was assessed using multi-level regression analysis to estimate individual and between-sites variance adjusting for age, sex, education, migrant, employment and relational status, childhood adversity, and cannabis use. In the final model we added local FEP incidence as a second-level variable. Association with genetic liability was examined separately. RESULTS: Schizotypy showed a large between-sites variation with up to 15% of variance attributable to site-level characteristics. Adding local FEP incidence to the model considerably reduced the between-sites unexplained schizotypy variance. PLEs did not show as much variation. Overall, SP was associated with younger age, migrant, unmarried, unemployed and less educated individuals, cannabis use, and childhood adversity. Both phenotypes were associated with genetic liability to schizophrenia. CONCLUSIONS: Schizotypy showed substantial between-sites variation, being more represented in areas where FEP incidence is higher. This supports the hypothesis that shared contextual factors shape the between-sites variation of psychosis across the spectrum.
Original languageEnglish
Pages (from-to)1810-1823
Number of pages14
JournalPsychological Medicine
Volume54
Issue number8
Early online date30 Jan 2024
DOIs
Publication statusPublished - Jun 2024

Keywords

  • incidence of psychosis
  • psychosis epidemiology
  • psychosis prevention
  • psychosis spectrum
  • psychotic experiences
  • schizotypy
  • subclinical psychosis

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