Premorbid Adjustment and IQ in Patients With First-Episode Psychosis: A Multisite Case-Control Study of Their Relationship With Cannabis Use

WP2 EU-GEI GROUP, Silvia Amoretti, Grégoire Baudin, Stephanie Beards, Domenico Berardi, Chiara Bonetto, Bibiana Cabrera, Angel Carracedo, Thomas Charpeaud, Javier Costas, Doriana Cristofalo, Pedro Cuadrado, Aziz Ferchiou, Nathalie Franke, Flora Frijda, Enrique García Bernardo, Paz Garcia-Portilla, Javier González Peñas, Emiliano González, Kathryn HubbardStéphane Jamain, Estela Jiménez-López, Antonio Lasalvia, Marion Leboyer, Gonzalo López Montoya, Esther Lorente-Rovira, Covadonga M Díaz-Caneja, Camila Marcelino Loureiro, Giovanna Marrazzo, Covadonga Martínez, Mario Matteis, Elles Messchaart, Ma Dolores Moltó, Carmen Moreno, Nacher Juan, Ma Soledad Olmeda, Mara Parellada, Baptiste Pignon, Marta Rapado, Jean Romain Richard, José Juan Rodríguez Solano, Paulo Rossi Menezes, Mirella Ruggeri, Pilar A. Sáiz, Teresa Sánchez-Gutierrez, Emilio Sánchez, Crocettarachele Sartorio, Franck Schürhoff, Fabio Seminerio, Rosana Shuhama, Simona A. Stilo, Fabian Termorshuizen, Sarah Tosato, Anne Marie Tronche, Daniella Van Dam, Elsje Van Der Ven

Research output: Contribution to journalArticleAcademicpeer-review


Psychotic patients with a lifetime history of cannabis use generally show better cognitive functioning than other psychotic patients. Some authors suggest that cannabis-using patients may have been less cognitively impaired and less socially withdrawn in their premorbid life. Using a dataset comprising 948 patients with first-episode psychosis (FEP) and 1313 population controls across 6 countries, we examined the extent to which IQ and both early academic (Academic Factor [AF]) and social adjustment (Social Factor [SF]) are related to the lifetime frequency of cannabis use in both patients and controls. We expected a higher IQ and a better premorbid social adjustment in psychotic patients who had ever used cannabis compared to patients without any history of use. We did not expect such differences in controls. In both patients and controls, IQ was 3 points higher among occasional-users than in never-users (mean difference [Mdiff] = 2.9, 95% CI = [1.2, 4.7]). Both cases and control daily-users had lower AF compared to occasional (Mdiff = -0.3, 95% CI = [-0.5; -0.2]) and never-users (Mdiff = -0.4, 95% CI = [-0.6; -0.2]). Finally, patient occasional (Mdiff = 0.3, 95% CI = [0.1; 0.5]) and daily-users (Mdiff = 0.4, 95% CI = [0.2; 0.6]) had better SF than their never-using counterparts. This difference was not present in controls (Fgroup*frequency(2, 2205) = 4.995, P = .007). Our findings suggest that the better premorbid social functioning of FEP with a history of cannabis use may have contributed to their likelihood to begin using cannabis, exposing them to its reported risk-increasing effects for Psychotic Disorders.

Original languageEnglish
Pages (from-to)517-529
Number of pages13
JournalSchizophrenia Bulletin
Issue number3
Publication statusPublished - 10 Apr 2020


  • cognition
  • education
  • marijuana
  • preillness
  • schizophrenia
  • sociability

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