Daily use of high-potency cannabis is associated with more positive symptoms in first-episode psychosis patients: The EU-GEI case-control study

Daniele La Barbera, Giada Tripoli, Caterina La Cascia, Laura Ferraro, Marta Di Forti, Ilaria Tarricone, Tom P. Freeman, Robin M. Murray, Ulrich Reininghaus, Charlotte Gayer-Anderson, Craig Morgan, Evangelos Vassos, Alastair G. Cardno, Julio Sanjuán, James B. Kirkbride, Peter B. Jones, Jose Luis Santos, Harriet Quigley, Eva Velthorst, Jim Van OsMiquel Bernardo, Antonio Lasalvia, Giada Tripoli, Hannah E. Jongsma, Charlotte Gayer-Anderson, Robin M. Murray, Cristina Marta Del Ben, Peter B. Jones, Domenico Berardi, Pak C. Sham, Cristina Marta Del Ben, Michael T. Lynskey, Sarah Tosato, Cathryn M. Lewis, Giusy Gatto, Simona Del Peschio, Andrea Quattrone, Tom P. Freeman, Paulo Rossi Menezes, Andrea Tortelli, Celso Arango, Bart P.F. Rutten, Pierre-Michel Llorca, Michael T. Lynskey, Paulo Rossi Menezes, Lieuwe De Haan, Julio Bobes, Andrei Szöke, Cathryn M. Lewis, Sarah Tosato, Diego Quattrone

Research output: Contribution to journalArticle

Abstract

BackgroundDaily use of high-potency cannabis has been reported to carry a high risk for developing a psychotic disorder. However, the evidence is mixed on whether any pattern of cannabis use is associated with a particular symptomatology in first-episode psychosis (FEP) patients.MethodWe analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We used item response modelling to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use were evaluated using linear mixed-effects models analyses.ResultsIn patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high-potency cannabis having the highest score (B = 0.35; 95% CI 0.14-0.56). Moreover, negative symptoms were more common among patients who never used cannabis compared with those with any pattern of use (B = -0.22; 95% CI -0.37 to -0.07). In controls, psychotic experiences were associated with current use of cannabis but not with the extent of lifetime use. Neither patients nor controls presented differences in depressive dimension related to cannabis use.ConclusionsOur findings provide the first large-scale evidence that FEP patients with a history of daily use of high-potency cannabis present with more positive and less negative symptoms, compared with those who never used cannabis or used low-potency types.
Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalPsychological Medicine
Publication statusPublished - 2020

All Science Journal Classification (ASJC) codes

  • Applied Psychology
  • Psychiatry and Mental health

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    La Barbera, D., Tripoli, G., La Cascia, C., Ferraro, L., Di Forti, M., Tarricone, I., Freeman, T. P., Murray, R. M., Reininghaus, U., Gayer-Anderson, C., Morgan, C., Vassos, E., Cardno, A. G., Sanjuán, J., Kirkbride, J. B., Jones, P. B., Santos, J. L., Quigley, H., Velthorst, E., ... Quattrone, D. (2020). Daily use of high-potency cannabis is associated with more positive symptoms in first-episode psychosis patients: The EU-GEI case-control study. Psychological Medicine, 1-9.