Differences in Patterns of Stimulant Use and Their Impact on First-Episode Psychosis Incidence: An Analysis of the EUGEI Study
Authors: Rodríguez-Toscano Elisa , Alloza Clara , Fraguas David , Durán-Cutilla Manuel , Roldán Laura , Sánchez-Gutiérrez Teresa , López-Montoya Gonzalo , Parellada Mara , Moreno Carmen , Gayer-Anderson Charlotte , Jongsma Hannah E , Di Forti Marta , Quattrone Diego , Velthorst Eva , de Haan Lieuwe , Selten Jean-Paul , Szöke Andrei , Llorca Pierre-Michel , Tortelli Andrea , Bobes Julio , Bernardo Miguel , Sanjuán Julio , Luis Santos José , Arrojo Manuel , Tarricone Ilaria , Berardi Domenico , Ruggeri Mirella , Lasalvia Antonio , Ferraro Laura , La Cascia Caterina , La Barbera Daniele , Menezes Paulo Rossi , Del-Ben Cristina Marta ,   EU-GEI WP2 Group, Amoretti Silvia , Andreu-Bernabeu Alvaro , Baudin Grégoire , Beards Stephanie , Bonora Elena , Bonetto Chiara , Cabrera Bibiana , Carracedo Angel , Charpeaud Thomas , Costas Javier , Cristofalo Doriana , Cuadrado Pedro , D’Andrea Giuseppe , Ferchiou Aziz , Franke Nathalie , Frijda Flora , Garcia-Portilla Paz , González Emiliano , Hubbard Kathryn , Jamain Stéphane , Jiménez-López Estela , Leboyer Marion , Lorente-Rovira Esther , Marcelino Loureiro Camila , Marrazzo Giovanna , Matteis Mario , Messchaart Elles , Mezquida Gisela , Pignon Baptiste , Rapado Marta , Richard Jean-Romain , Rodríguez Solano José Juan , Ruggeri Mirella , Sánchez Emilio , Sartorio Crocettarachele , Schürhoff Franck , Seminerio Fabio , Seri Marco , Shuhama Rosana , Sideli Lucia , Stilo Simona A , Termorshuizen Fabian , Tripoli Giada , Tronche Anne-Marie , van Dam Daniella , van der Ven Elsje , Stilo Simona , Rutten Bart P , van Os Jim , Jones Peter B , Murray Robin M , Kirkbride James B , Morgan Craig , Díaz-Caneja Covadonga M , Arango Celso 
Published: July 2023

Abstract

Background
Use of illegal stimulants is associated with an increased risk of psychotic disorder. However, the impact of stimulant use on odds of first-episode psychosis (FEP) remains unclear. Here, we aimed to describe the patterns of stimulant use and examine their impact on odds of FEP.

Methods
We included patients with FEP aged 18–64 years who attended psychiatric services at 17 sites across 5 European countries and Brazil, and recruited controls representative of each local population (FEP = 1130; controls = 1497). Patterns of stimulant use were described. We computed fully adjusted logistic regression models (controlling for age, sex, ethnicity, cannabis use, and education level) to estimate their association with odds of FEP. Assuming causality, we calculated the population-attributable fractions for stimulant use associated with the odds for FEP.

Findings
Prevalence of lifetime and recent stimulant use in the FEP sample were 14.50% and 7.88% and in controls 10.80% and 3.8%, respectively. Recent and lifetime stimulant use was associated with increased odds of FEP compared with abstainers [fully adjusted odds ratio 1.74,95% confidence interval (CI) 1.20–2.54, P = .004 and 1.62, 95% CI 1.25–2.09, P &lt; .001, respectively]. According to PAFs, a substantial number of FEP cases (3.35% [95% CI 1.31–4.78] for recent use and 7.61% [95% CI 3.68–10.54] for lifetime use) could have been prevented if stimulants were no longer available and the odds of FEP and PAFs for lifetime and recent stimulant use varied across countries.

Interpretation
Illegal stimulant use has a significant and clinically relevant influence on FEP incidence, with varying impacts across countries.