title: Association between cannabis use and schizotypal dimensions--a meta-analysis of cross-sectional studies.
abstract: Cannabis consumption can cause abuse and dependence and increase risk of developing psychiatric and somatic disorders. Several literature reviews explored the link between cannabis consumption and schizophrenia but none summarized the rich literature on cannabis and psychometric schizotypy. The aim of our review is to synthesize data from studies that explored the association between cannabis consumption and schizoptypal dimensions. A systematic review of the literature and, when needed, contact with the authors, allowed us to gather data from 29 cross-sectional studies. We compared schizotypy scores between subjects that never used cannabis and subjects that used it at least once ("never vs. ever") and between current users and subjects that do not use cannabis currently ("current vs. other"). We conducted separate analyses for total schizotypy score and each of the three classical schizotypal dimensions (positive, negative, disorganized). For all eight comparisons, the cannabis group ("ever" or "current") had higher schizotypy scores. Differences were in the small or medium range and, with the exception of the negative score in the current vs. other comparison, statistically significant. Cannabis consumption is associated with increased schizotypal traits. More research, using different approaches (e.g. longitudinal studies) is needed to explore the cause of this association.
authors.affiliation: AP-HP, Groupe Hospitalier "Mondor", Pôle de Psychiatrie, Créteil 94000, France; INSERM, U955, Equipe 15, Créteil 94000, France; Université Paris-Est, Faculté de médecine, Créteil 94000, France; Fondation Fondamental, Créteil 94000, France. Electronic address: andrei.szoke@inserm.fr.
authors.forename: Andrei
authors.initials: A
authors.lastname: Szoke
authors.affiliation: AP-HP, Groupe Hospitalier "Mondor", Pôle de Psychiatrie, Créteil 94000, France; INSERM, U955, Equipe 15, Créteil 94000, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Galliot
authors.affiliation: INSERM, U955, Equipe 15, Créteil 94000, France; Fondation Fondamental, Créteil 94000, France.
authors.forename: Jean-Romain
authors.initials: JR
authors.lastname: Richard
authors.affiliation: AP-HP, Groupe Hospitalier "Mondor", Pôle de Psychiatrie, Créteil 94000, France; INSERM, U955, Equipe 15, Créteil 94000, France.
authors.forename: Aziz
authors.initials: A
authors.lastname: Ferchiou
authors.affiliation: AP-HP, Groupe Hospitalier "Mondor", Pôle de Psychiatrie, Créteil 94000, France; INSERM, U955, Equipe 15, Créteil 94000, France.
authors.forename: Grégoire
authors.initials: G
authors.lastname: Baudin
authors.affiliation: AP-HP, Groupe Hospitalier "Mondor", Pôle de Psychiatrie, Créteil 94000, France; INSERM, U955, Equipe 15, Créteil 94000, France; Université Paris-Est, Faculté de médecine, Créteil 94000, France; Fondation Fondamental, Créteil 94000, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Leboyer
authors.affiliation: AP-HP, Groupe Hospitalier "Mondor", Pôle de Psychiatrie, Créteil 94000, France; INSERM, U955, Equipe 15, Créteil 94000, France; Université Paris-Est, Faculté de médecine, Créteil 94000, France; Fondation Fondamental, Créteil 94000, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Schürhoff
mesh_terms: D002188:Cannabis / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D002189:Marijuana Abuse / Q000150:complications / Q000523:psychology*; D008385:Marijuana Smoking / Q000009:adverse effects* / Q000523:psychology; D011594:Psychometrics; D012569:Schizotypal Personality Disorder / Q000150:complications / Q000523:psychology*
keywords: Psychosis; Review; Schizotypy; Substance-related disorders