Premorbid Adjustment and IQ in Patients With First-Episode Psychosis: A Multisite Case-Control Study of Their Relationship With Cannabis Use
Laura Ferraro, Caterina la Cascia, Diego Quattrone, Lucia Sideli, Domenica Matranga, Veronica Capuccio, Giada Tripoli, Charlotte Gayer‐Anderson, Craig Morgan, Musa Basseer Sami, Pak Chung Sham, Lieuwe de Haan, Eva Velthorst, Hannah E. Jongsma, James Bowes Kirkbride, Bart P. F. Rutten, Alexander L. Richards, Laura Castro Roldán, Celso Arango, Miquel Bernardo, Julio Bobes, Julio Sanjuán, José Luis Santos, Manuel Arrojo, Ilaria Tarricone, Andrea Tortelli, Andreı̈ Szöke, Cristina Marta Del‐Ben, Jean-Paul Selten, Michael T. Lynskey, Peter Brian Jones, Jim van Os, Daniele la Barbera, Wp2 Eu-Gei Group, Sílvia 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 Hubbard, Stéphane 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‐Gutiérrez, Emilio Sánchez, Crocettarachele Sartorio, Franck Schürhoff, Fabio Seminerio, Rosana Shuhama, Simona A. Stilo, Fabian Termorshuizen, Sarah Tosato, Anne-Marie Tronche, Daniëlla S. van Dam, Elsje van der Ven, Robin Murray, Marta Di Forti
Schizophrenia Bulletin July 2, 2019 DOI: 10.1093/schbul/sbz077 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Sample size | 2,261 |
| Population | 948 patients with first-episode psychosis and 1313 population controls across 6 countries |
| Measures | IQ, Academic Factor (AF), Social Factor (SF) |
| Topics | Cannabis |
| Citations | 25 |
| Key findings | IQ was about 3 points higher among occasional cannabis users than never-users in both patients and controls, while daily users had lower early academic adjustment. Patient occasional and daily users had better premorbid social adjustment than never-users, a difference absent in controls. The authors propose that better premorbid social functioning may have increased patients' likelihood of starting cannabis use, exposing them to its reported risk-increasing effects for psychotic disorders. |
Abstract
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.
Comparable studies
Other observational and cohort studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population | 2009 | Case-control study | n = 454 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people | 2000 | Observational | |
| Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline | 2011 | Observational cohort | n = 1,923 |
| Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... | 2005 | Observational cohort | n = 535 |