Search

Objective: Increasing number of studies show an association between adult ADHD (a-ADHD) and posttraumatic stress disorder (PTSD). We explored this association in alcohol use disorder (AUD) inpatients. Method: In total, 551 inpatients cross-sectionally completed self-administered questionnaires regarding sociodemographics, lifetime trauma exposure, PTSD Checklist for DSM-5, Adult ADHD Self-Report Scale (ASRS), and Wender Utah Rating Scale (WURS). We considered self-reported a-ADHD when ASRS and WURS had significant scores. Results: Prevalence for a-ADHD was 20%. PTSD prevalence was higher in a-ADHD patients (84% vs. 40%; p < .001). They also were younger ( p < .001) and women ( p = .015). Adult ADHD was associated with more traumatic events, and symptoms were correlated with PTSD severity. After adjusting for age, gender and marital status, PTSD severity was associated with a-ADHD. Conclusion: Our study confirms that a-ADHD is associated with PTSD in AUD inpatients, and thus, may represent a specific subpopulation. Future studies should explore implication of this dual diagnosis on AUD and treatment outcome.

The influence of psychosocial stressors on psychosis risk has usually been studied in isolation and after the onset of the disorder, potentially ignoring important confounding relationships or the fact that some stressors that may be the consequence of the disorder rather than preexisting. The study of subclinical psychosis could help to address some of these issues. In this study, we investigated whether there was (i) an association between dimensions of subclinical psychosis and several psychosocial stressors including: childhood trauma, self-reported discrimination experiences, low social capital, and stressful life experiences, and (ii) any evidence of environment-environment (ExE) interactions between these factors. Data were drawn from the EUGEI study, in which healthy controls (N = 1497) and siblings of subjects with a psychotic disorder (N = 265) were included in six countries. The association between psychosocial stressors and subclinical psychosis dimensions (positive, negative and depressive dimension as measured by the Community Assessment of Psychic Experiences (CAPE) scale) and possible ExE interactions were assessed using linear regression models. After adjusting for sex, age, ethnicity, country, and control/sibling status, childhood trauma (beta for positive dimension: 0.13, negative: 0.49, depressive: 0.26) and stressful life events (positive: 0.08, negative: 0.16, depressive: 0.17) were associated with the three dimensions. Lower social capital was associated with the negative and depression dimensions (negative: 0.26, depressive: 0.13), and self-reported discrimination experiences with the positive dimension (0.06). Our findings are in favor of independent, cumulative and non-specific influences of social adversities in subclinical psychosis in non-clinical populations, without arguments for E * E interactions. © The Author(s) 2021. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The study of subclinical psychotic manifestations (quantitative schizotypy) represents clinical and public health issues. These manifestations are more common than schizophrenia or depression, but rarely identified while it impacts the quality of life. Screening schizotypy in the general population would make it possible to propose prevention strategies. The objectives of the present research is to better understand the determinants and mechanisms of schizotypy in order to identify population...

Objective To explore the sociodemographic characteristics that might explain the increased incidence of psychosis among immigrants and their descendants in France. Methods Data were collected for all subjects with first contact for psychosis aged between 18 and 64 years, in two catchment areas in the Paris region. Incidence rates (IR) and incidence rate ratios (IRR) were adjusted for gender and age. Results During 805,396 persons‐year at risk, we identified 321 cases of first‐episode psychosis, of which 129 were immigrants and 78 descendants of immigrants. We found that the geographic origin was associated with the risk of psychosis although generation has little impact. Sub‐Saharan African immigrants and their descendants showed the highest risk (IRR = 3.1 and IRR = 2.9, respectively). We observed that living in deprived areas increased the incidence of psychosis (IRR = 1.3, 95CI%: 1.0–1.6), particularly among immigrants (IRR = 1.6; 95% CI: 1.1–2.5). Finally, our study showed that subjects having unstable housing (a proxy for “hard to count population”) could inflate the incidence rates among immigrants. Conclusion The current study shows that the increased risk of psychosis in groups with an immigration background in France is associated with their origin and highlights the importance of socioeconomic factors in modulating this risk., The aim of the present study is to explore the characteristics that might explain this increase: geographic origin, generation (immigrants or their descendants), social environment, and living conditions. We observed that living in deprived areas increased the incidence of psychosis, particularly among immigrants. Geographic origin was associated with the risk of psychosis although generation has little impact and Sub‐Saharan African immigrants and their descendants showed the highest risk.

Post-traumatic stress disorder (PTSD) is highly prevalent among patients hospitalized for an alcohol use disorder (AUD). Hospitalization can improve PTSD and AUD outcomes in some but not all patients, but we lack data on the baseline predictors of PTSD non-remission. This study aimed to determine the baseline risk factors for non-remitted PTSD in patients hospitalized for an AUD. Of 298 AUD inpatients recruited in a rehabilitation center (Le Courbat, France), we included 91 AUD inpatients with a co-occurring PTSD and a longitudinal assessment at baseline (T1) and before discharge (T2: 8 weeks later). Patients were assessed for PTSD diagnosis/severity (PCL-5=PTSD Checklist for DSM-5), different types of trauma including childhood trauma (LEC-5=Life Events Checklist for DSM-5/CTQ-SF=Childhood Trauma Questionnaire, Short-Form), and AUD diagnosis/severity (clinical interview/AUDIT=Alcohol Use Disorders Identification Test). Rate of PTSD remission between T1 and T2 was 74.1%. Non-remitted PTSD at T2 was associated with a history of childhood trauma (physical, emotional or sexual abuse, physical negligence), but not with other types of trauma experienced, nor baseline PTSD or AUD severity. Among patients hospitalized for an AUD with co-occurring PTSD, PTSD remission was more strongly related to the existence of childhood trauma than to AUD or PTSD severity at admission. These patients should be systematically screened for childhood trauma in order to tailor evidence-based interventions.

International audience; Objectives: We assessed the effect of invalid responding on factor structure and on scores of schizotypy through the factor analysis of the Schizotypal Personality Questionnaire-Brief (SPQ-B) in a sample of 580 Romanian students using 3 validity items and 5 social desirability items.Methods: We examined the factor structure of the SPQ-B, we compared the mean SPQ-B scores between reliable and unreliable responders and between high vs. low social desirability responders, and we re-run the factor analysis restricting the sample to the reliable or low social desirability responders.Results: Factor analysis resulted in a 3-factor solution: Cognitive-perceptual, Interpersonal and Disorganized dimensions. Unreliable responders had lower scores of positive, negative and total schizotypy. Subjects with high social desirability scores had lower scores of disorganized schizotypy. Factor analyses in the samples of "good" responders showed minor differences in reliable responders, whereas, after taking into account the effect of social desirability, 2 items correctly loaded on expected dimensions.Conclusions: Random responding and social desirability could influence scores of schizotypy and factor structure. Simple methods could be used to identify invalid responses. The effect of social desirability could be linked to the phrasing of items.

Cet article aborde les déterminants des troubles psychotiques à travers l’étude des manifestations psychotiques « atténuées » (ou schizotypie quantitative) ; manifestations plus fréquentes que les troubles constitués (telle que la schizophrénie) mais rarement identifiés et pris en charge alors qu’ils impactent la qualité de vie. Si les déterminants individuels de ces troubles « atténués » sont plutôt bien connus, l’impact des déterminants contextuels (caractéristiques sociales, urbanistiques) des lieux de vie sur leur présence ou leur intensité n’a, par contre, pas encore été étudié. Les relations entre contexte de résidence et schizophrénie ont, en revanche, fait l’objet de recherches spécifiques. A partir de données recueillies auprès de 255 adultes résidant dans trois quartiers de la commune de Créteil, cette étude s’intéresse aux relations entre les représentations (dont l’étendue) du quartier de résidence, les caractéristiques (socio-démographiques et urbanistiques) du quartier et les scores de schizotypie. The study of subclinical psychotic manifestations (quantitative schizotypy) represents clinical and public health issues. These manifestations are more common than schizophrenia or depression, but rarely identified while it impacts the quality of life. Screening schizotypy in the general population would make it possible to propose prevention strategies. The objectives of the present research is to better understand the determinants and mechanisms of schizotypy in order to identify population at risk and hopefully be able to improve prevention and care. The hypothesis is that schizotypy is influenced both by individual and contextual characteristics (social, built). Based on data collected during a survey in the city of Créteil, the aims of this article were to explore the relationships between representations (including size), socioeconomic and urban planning characteristics of the neighborhood of residence and schizotypy scores. In addition, a methodological contribution of this article is to measure and characterize self-defined neighborhoods.

International audience

Resume Introduction Des les premieres descriptions nosographiques de la schizophrenie, des hypotheses sur des liens entre processus dissociatifs et symptomes psychotiques ont ete emises. Quoique ne beneficiant pas d’un large retentissement aupres des chercheurs et des cliniciens, ces hypotheses commencent a etre etayees par une litterature croissante. Cependant, elles manquent d’un cadre theorique qui permettrait de rassembler les donnees existantes en un ensemble coherent. Objectif Dans cet article, nous nous proposons, d’une part, de presenter les travaux faisant des liens entre experiences traumatiques infantiles, processus dissociatifs et symptomes psychotiques et, d’autre part, de presenter des modeles qui permettront d’integrer ces travaux au sein d’un cadre theorique coherent. Methodes Nous avons mene une revue de la litterature concernant, d’une part, les modeles etiopathogeniques des troubles psychotiques et, d’autre part, les liens entre processus dissociatifs et troubles psychotiques. Resultats La litterature indique une forte prevalence d’exposition a des experiences traumatiques parmi les personnes qui souffrent de troubles psychotiques et, chez certaines d’entre elles, la presence de processus dissociatifs intenses. Un des modeles theoriques presentes, la theorie de la dissociation structurelle de la personnalite, issue des travaux de Pierre Janet, repond particulierement a notre deuxieme objectif d’integrer les donnees de la litterature. Conclusion Nous presentons des arguments en faveur d’une psychologie janetienne des psychoses et developpons des perspectives theoriques, therapeutiques et de recherche qu’une telle modelisation des troubles psychotiques offre.

Resume Introduction Les representations sociales concernant les auteurs de violences sexuelles (AVS) sont habituellement pejoratives. L’objectif de cette etude est l’elaboration d’une echelle d’evaluation de ces representations, la comparaison des attitudes des professionnels a la population generale, la prise en compte des antecedents de violences sexuelles subies, des traits de personnalite et de la detresse emotionnelle eventuelle des repondants. Methode L’echantillon comptait 405 personnes (âge moyen : 25,51 ; ecart-type : 9,70), dont 58 % de femmes. Parmi eux, 36 % travaillaient dans le soin, dont 7 % dans un CRIAVS ou une unite de prise en charge des AVS. Le materiel comportait : un questionnaire de 27 items sur les representations sociales negatives concernant les AVS ; l’echelle d’Attitudes Towards Sex offenders (ATS 21), le Big Five Inventory (BFI-10 items) et le General Health Questionnaire (GHQ-12 items). Resultats L’analyse factorielle a partir des reponses aux items de representations sociales negatives des AVS a mis en evidence deux facteurs qui expliquaient plus de 45 % de variance : Rejet des auteurs de violences sexuelles et Personnes malades, avec des coefficients alpha de Cronbach de 0,94 et 0,67. Il existait aussi de fortes correlations avec l’ATS. Les resultats ont montre des representations plus pejoratives chez les plus jeunes et ceux qui ont le niveau d’etudes le plus bas, chez les hommes par rapport aux femmes, les personnes vivant en milieu rural par rapport au milieu urbain ou peri-urbain. Les personnes travaillant dans le soin et surtout dans un CRIAVS avaient des representations plus favorables. Il existait un lien entre ces attitudes negatives et le Nevrosisme, ainsi qu’avec la morbidite psychique. Discussion Il s’agit d’une premiere etape d’elaboration d’une echelle des representations sociales negatives concernant les auteurs de violences sexuelles.

Resume L’objectif de notre etude etait d’analyser la structure factorielle de la version breve du Questionnaire de Personnalite Schizotypique (SPQ-B) dans un format Likert. Une analyse en composante principale de la version francaise de l’echelle a ete realisee dans un echantillon representatif de la population generale ( n = 233). La consistance interne et l’influence de l’âge et du sexe sur le score total et les sous-scores dimensionnels ont egalement ete etudiees. L’echantillon etait constitue de 131 femmes et de 102 hommes avec un âge moyen de 52,7 ± 18,1 ans et un score moyen du SPQ-B de 43,6 ± 13. L’analyse factorielle a montre une solution a 3 facteurs expliquant 47,7 % de la variance, avec un facteur « desorganisation » incluant les items du « comportement bizarre », du « discours bizarre » et de « l’anxiete sociale », un facteur « interpersonnel » incluant les items de la dimension negative et de la « mefiance », et un facteur « cognitif-perceptif » incluant les principaux items de la dimension positive. La consistance interne (coefficient α de Cronbach) pour les 3 sous-echelles et pour le score total etait respectivement de 0,81, 0,81, 0,77 et 0,88. Nous n’avons pas retrouve d’influence de l’âge et du sexe sur les differents scores de schizotypie. Notre etude confirme la structure tridimensionnelle de la schizotypie et montre que la version francaise du SPQ-B format Likert presente de bonnes qualites psychometriques. Cet outil apparait comme un instrument fiable et facile d’utilisation pour mesurer l’intensite des traits schizotypiques en population non malade.

Importance: Psychotic disorders contribute significantly to the global disease burden, yet the latest international incidence study of psychotic disorders was conducted in the 1980s. Objectives: To estimate the incidence of psychotic disorders using comparable methods across 17 catchment areas in 6 countries and to examine the variance between catchment areas by putative environmental risk factors. Design, Setting, and Participants: An international multisite incidence study (the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions) was conducted from May 1, 2010, to April 1, 2015, among 2774 individuals from England (2 catchment areas), France (3 catchment areas), Italy (3 catchment areas), the Netherlands (2 catchment areas), Spain (6 catchment areas), and Brazil (1 catchment area) with a first episode of nonorganic psychotic disorders (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] codes F20-F33) confirmed by the Operational Criteria Checklist. Denominator populations were estimated using official national statistics. Exposures: Age, sex, and racial/ethnic minority status were treated as a priori confounders. Latitude, population density, percentage unemployment, owner-occupied housing, and single-person households were treated as catchment area-level exposures. Main Outcomes and Measures: Incidence of nonorganic psychotic disorders (ICD-10 codes F20-F33), nonaffective psychoses (ICD-10 codes F20-F29), and affective psychoses (ICD-10 codes F30-F33) confirmed by the Operational Criteria Checklist. Results: A total of 2774 patients (1196 women and 1578 men; median age, 30.5 years [interquartile range, 23.0-41.0 years]) with incident cases of psychotic disorders were identified during 12.9 million person-years at risk (crude incidence, 21.4 per 100 000 person-years; 95% CI, 19.4-23.4 per 100 000 person-years). A total of 2183 patients (78.7%) had nonaffective psychotic disorders. After direct standardization for age, sex, and racial/ethnic minority status, an 8-fold variation was seen in the incidence of all psychotic disorders, from 6.0 (95% CI, 3.5-8.6) per 100 000 person-years in Santiago, Spain, to 46.1 (95% CI, 37.3-55.0) per 100 000 person-years in Paris, France. Rates were elevated in racial/ethnic minority groups (incidence rate ratio, 1.6; 95% CI, 1.5-1.7), were highest for men 18 to 24 years of age, and were lower in catchment areas with more owner-occupied homes (incidence rate ratio, 0.8; 95% CI, 0.7-0.8). Similar patterns were observed for nonaffective psychoses; a lower incidence of affective psychoses was associated with higher area-level unemployment (incidence rate ratio, 0.3; 95% CI, 0.2-0.5). Conclusions and Relevance: This study confirmed marked heterogeneity in risk for psychotic disorders by person and place, including higher rates in younger men, racial/ethnic minorities, and areas characterized by a lower percentage of owner-occupied houses., The European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) Project is funded by grant agreement HEALTH-F2-2010-241909 (Project EU-GEI) from the European Community’s Seventh Framework Programme. The Brazilian study was funded by grant 2012/0417-0 from the São Paulo Research Foundation. Dr Kirkbride is funded by the Wellcome Trust and grant 101272/Z/13/Z from the Royal Society. Ms Jongsma and Dr Jones are funded by the National Institute of Health Research Collaboration of Leadership in Applied Health Research and Care East of England.

International audience

Objectives Incidence-prevalence-mortality (IPM) models have been developped to estimate incidence or prevalence when one of these two measures is unavailable. We aimed to test the consistency of an IPM model of psychotic disorders on a recent incidence-prevalence couple dataset and to identify potential causes of inconsistency by applying the model to (a) the whole population, (b) female and male subgroups, (c) migrant subgroups, and (d) psychotic disorders with age at onset (AAO) between 18 and 24 (18-24 AAO). Methods We modelled prevalence (MP) using incidence data and the expected mortality and remission values. We then compared the MP to the observed prevalence (OP). Results In the whole population, the model significantly underestimated the prevalence (MP = 3.30, 95% CI [2.97, 3.66]; OP = 4.98, 95% CI [4.58, 5.41]). The results were similar for the two genders. In the migrants group, results were in the opposite direction, the model significantly overestimating the prevalence. Finally, in the 18-24 AAO subgroup, the model performed well, with OP and MP not significantly different. Conclusion These results suggest that standard IPM models do not perform well for psychotic disorders and more complex models taking into account the heterogeneity of the sample (in terms of remission, mortality, population movements, etc.) need to be developed.

Childhood traumas have been extensively associated with the development of psychotic disorders. However, our understanding of processes underlying this relationship remains poor. In order to address this issue, we examined which specific aspects of childhood trauma are significantly associated with a first episode of psychosis. 109 patients with first episode of psychosis and 145 controls representative from general population were recruited in three centers in France. Child experiences of care and abuses allowed obtaining information about types of childhood trauma, age at first exposure, identity of perpetrator, and social support. Odds ratio were calculated for each of these aspects, adjusted for age, sex, and education. Sexual and physical abuses (OR=2.26 (1.19-4.32)), and separation from one or both parents (OR ranging from 1.94 to 3.17; all significant) are significantly associated with an increased risk to present a first episode of psychosis. Furthermore, separation from mother occurring before age of 4 (OR=5.96 (1.24-28.77)), and sexual and physical abuses perpetrated by someone other than parents (OR=4.61 (1.66-12.80)) were also associated with an increased risk of first episode of psychosis. Finally, social support was significantly associated with a decreased risk to develop psychotic disorders (OR ranging from 0.33 to 0.42; all significant). Together, these findings suggest that some but not all aspects of childhood trauma are related to a significant risk to develop a first episode of psychosis.

Previous analyses of neighbourhood variations of non-affective psychotic disorders (NAPD) have focused mainly on incidence. However, prevalence studies provide important insights on factors associated with disease evolution as well as for healthcare resource allocation. This study aimed to investigate the distribution of prevalent NAPD cases in an urban area in France. The number of cases in each neighbourhood was modelled as a function of potential confounders and ecological variables, namely: migrant density, economic deprivation and social fragmentation. This was modelled using statistical models of increasing complexity: frequentist models (using Poisson and negative binomial regressions), and several Bayesian models. For each model, assumptions validity were checked and compared as to how this fitted to the data, in order to test for possible spatial variation in prevalence. Data showed significant overdispersion (invalidating the Poisson regression model) and residual autocorrelation (suggesting the need to use Bayesian models). The best Bayesian model was Leroux’s model (i.e. a model with both strong correlation between neighbouring areas and weaker correlation between areas further apart), with economic deprivation as an explanatory variable (OR = 1.13, 95% CI [1.02–1.25]). In comparison with frequentist methods, the Bayesian model showed a better fit. The number of cases showed non-random spatial distribution and was linked to economic deprivation.

We sought to determine whether significant variation in the incidence of clinically relevant psychoses existed at an ecological level in an urban French setting, and to examine possible factors associated with this variation. We aimed to advance the literature by testing this hypothesis in a novel population setting and by comparing a variety of spatial models.We sought to identify all first episode cases of non-affective and affective psychotic disorders presenting in a defined urban catchment area over a 4 years period, over more than half a million person-years at-risk. Because data from geographic close neighbourhoods usually show spatial autocorrelation, we used for our analyses Bayesian modelling. We included small area neighbourhood measures of deprivation, migrants' density and social fragmentation as putative explanatory variables in the models.Incidence of broad psychotic disorders shows spatial patterning with the best fit for models that included both strong autocorrelation between neighbouring areas and weak autocorrelation between areas further apart. Affective psychotic disorders showed similar spatial patterning and were associated with the proportion of migrants/foreigners in the area (inverse correlation). In contrast, non-affective psychoses did not show spatial patterning.At ecological level, the variation in the number of cases and the factors that influence this variation are different for non-affective and affective psychotic disorders. Important differences in results-compared with previous studies in different settings-point to the importance of the context and the necessity of further studies to understand these differences.

European Community Recent years have seen considerable progress in epidemiological and molecular genetic research into environmental and genetic factors in schizophrenia, but methodological uncertainties remain with regard to validating environmental exposures, and the population risk conferred by individual molecular genetic variants is small. There are now also a limited number of studies that have investigated molecular genetic candidate gene-environment interactions (G x E), however, so far, thorough replication of findings is rare and G x E research still faces several conceptual and methodological challenges. in this article, we aim to review these recent developments and illustrate how integrated, large-scale investigations may overcome contemporary challenges in G x E research, drawing on the example of a large, international, multi-center study into the identification and translational application of G x E in schizophrenia. While such investigations are now well underway, new challenges emerge for G x E research from late-breaking evidence that genetic variation and environmental exposures are, to a significant degree, shared across a range of psychiatric disorders, with potential overlap in phenotype. Maastricht Univ, Med Ctr, Dept Psychiat & Neuropsychol, Sch Mental Hlth & Neurosci,South Limburg Mental H, NL-6200 MD Maastricht, Netherlands Kings Coll London, Inst Psychiat, Dept Psychosis Studies, London WC2R 2LS, England Mondriaan Mental Hlth Trust, Maastricht, Heerlen, Netherlands Univ Groningen, Univ Med Ctr Groningen, Rob Giel Clin Res, Univ Ctr Psychiat, Groningen, Netherlands Kings Coll London, Inst Psychiat, Dept Hlth Serv & Populat Res, London WC2R 2LS, England Kings Coll London, Inst Psychiat, Dept Psychol, London WC2R 2LS, England Cardiff Univ, MRC, Ctr Neuropsychiat Genet, Cardiff CF10 3AX, S Glam, Wales Cent Inst Mental Hlth, Dept Psychiat & Psychotherapy, Mannheim, Germany Dokuz Eylul Univ, Sch Med, Dept Psychiat, Konak, Turkey Istanbul Univ, Istanbul Fac Med, Dept Psychiat, Psychot Disorders Res Unit, Istanbul, Turkey Ankara Univ, Sch Med, Dept Psychiat, Cebeci Hosp, TR-06100 Ankara, Turkey Ankara Univ, Brain Res Ctr, TR-06100 Ankara, Turkey Yale Univ, Sch Med, Dept Psychiat, New Haven, CT USA Middle E Tech Univ, Dept Psychol, TR-06531 Ankara, Turkey Diskapi YB Res & Training Hosp, Ankara, Turkey Turkish Federat Schizophrenia Assoc, Ankara, Turkey Ataturk Training & Res Hosp, Psychiat Clin, Ankara, Turkey Manisa Mental Hlth Hosp, Manisa, Turkey Istanbul Univ, Expt Med Res Inst, Dept Adv Neurol Sci, Istanbul Fac Med, Istanbul, Turkey Univ Complutense, IiSGM CIBERSAM, Dept Child & Adolescent Psychiat, Hosp Gen Univ Gregorio Maranon,Sch Med, E-28040 Madrid, Spain Univ Barcelona, Dept Psychiat, Hosp Clin, IDIBAPS,Ctr Invest Biomed Red Salud Mental CIBERS, Barcelona, Spain Univ Valencia, Sch Med, Dept Psychiat, Ctr Invest Biomed Red Salud Mental CIBERSAM, Valencia, Spain Univ Oviedo, Sch Med, Dept Med,Psychiat Area, Ctr Invest Biomed Red Salud Mental CIBERSAM, Oviedo, Spain Univ Santiago de Compostela, Dept Mental Hlth & Drug Addit Assistance, Hlth Serv Galicia,Psychiat Genet Grp IDIS, Hosp Clin,Ctr Invest Biomedica Red Salud Mental C, Santiago de Compostela 15706, Spain Hosp Virgen de la Luz, Serv Psiquiat, Dept Psychiat, Cuenca, Spain Hosp Univ Infanta Leonor Hosp Virgen Torre, Villa de Vallecas Mental Hlth Ctr, Villa de Vallecas Mental Hlth Dept, Madrid, Spain Hosp Univ Infanta Leonor Hosp Virgen Torre, Puente de Vallecas Mental Hlth Dept, Ctr Salud Mental Puente Vallecas, Madrid, Spain Hosp Clin Univ, Fdn Publ Galega Med Xenomica, Santiago de Compostela, Spain Univ Complutense, Sch Med, Hosp Gen Univ Gregorio Maranon, Dept Psychiat, E-28040 Madrid, Spain Hosp Psiquiatr Conxo, Santiago de Compostela, Spain Univ Amsterdam, Acad Med Ctr, Early Psychosis Sect, Dept Psychiat, NL-1105 AZ Amsterdam, Netherlands Vrije Univ Amsterdam, Dept Clin Psychol, Amsterdam, Netherlands EMGO Inst Hlth & Care Res, Amsterdam, Netherlands Parnassia Psychiat Inst, Dept Psychosis Res, the Hague, Netherlands Rivierduinen Psychiat Inst, Leiden, Netherlands Grp Hosp Mondor, AP HP, Creteil, France Hop Henri Mondor, INSERM, U955, Equipe 15, F-94010 Creteil, France Univ Paris Est, Fac Med, Creteil, France Fdn Fondamental, Creteil, France CMP B CHU, F-63003 Clermont Ferrand 1, France Univ Auvergne, EA 7280, Clermont Ferrand, France EPS Maison Blanche, Paris, France UPC KU Leuven, Dept Neurosci, UPC, Kortenberg, Belgium UPC, Dept Neurosci, Res Grp Psychiat, Leuven, Belgium Katholieke Univ Leuven, Univ Hosp Gasthuisberg, Dept Human Genet, Leuven, Belgium Assoc Sci Res Multiple Births, Ghent, Belgium Univ Ghent, Dept Neurol, Ghent Univ Hosp, B-9000 Ghent, Belgium Univ Athens, Sch Med, Eginit Hosp, Athens 11528, Greece Med Univ Vienna, Dept Psychiat & Psychotherapy, Vienna, Austria Psychiat Univ Clin Basel, Ctr Gender Res & Early Detect, Basel, Switzerland Psychiat Univ Clin Basel, Diagnost & Crisis Intervent Ctr, Basel, Switzerland Univ Cologne, Dept Psychiat & Psychotherapy, D-50931 Cologne, Germany Univ Hong Kong, Li Ka Shing Fac Med, Ctr Genom Sci, State Key Lab Brain & Cognit Sci, Hong Kong, Hong Kong, Peoples R China Univ Hong Kong, Li Ka Shing Fac Med, Dept Psychiat, Hong Kong, Hong Kong, Peoples R China Univ Hong Kong, Queen Mary Hosp, Li Ka Shing Fac Med, State Key Lab Brain & Cognit Sci, Hong Kong, Hong Kong, Peoples R China Univ Hong Kong, Queen Mary Hosp, Li Ka Shing Fac Med, Dept Psychiat, Hong Kong, Hong Kong, Peoples R China Univ Basque Country, Univ Deusto, Interuniv Chair Law & Human Genome Prov Govt Bisk, Bilbao, Bizkaia, Spain Univ Zaragoza, Zaragoza, Spain Univ Cambridge, Dept Psychiat, Cambridge, England UCL, Div Psychiat, London, England Royal Coll Surgeons Ireland, Beaumont Hosp, Educ & Res Ctr, Dept Psychiat, Dublin 9, Ireland Univ Munich, Dept Psychiat, Div Mol & Clin Neurobiol, Munich, Germany Univ Bologna, Alma Mater Studiorium, Psychiat Unit, Dept Med & Surg Sci, Bologna, Italy Univ Bologna, Alma Mater Studiorium, Genet Unit, Dept Med & Surg Sci, Bologna, Italy Local Hlth Trust, Dept Mental Hlth & Pathol Addict, Bologna, Italy Univ Palermo, Sect Psychiat, Dept Expt Biomed & Clin Neurosci, Palermo, Italy P Giaccone Gen Hosp, Unit Psychiat, Palermo, Italy Univ Melbourne, Ctr Youth Mental Hlth, Parkville, Vic 3052, Australia Univ Melbourne, Melbourne Neuropsychiat Ctr, Carlton, Vic, Australia Univ São Paulo, Fac Med, Dept Med Prevent, BR-01246903 São Paulo, Brazil Univ São Paulo, Nucleo Pesquina Saude Mental Populac, São Paulo, Brazil Univ São Paulo, Fac Med Ribeirao Preto, Dept Neurociencias & Ciencias Comportamento, BR-14049 Ribeirao Preto, Brazil Univ Verona, Sect Psychiat, Dept Publ Hlth & Community Med, I-37100 Verona, Italy Copenhagen Univ Hosp, Res Unit, Mental Hlth Ctr Copenhagen, Copenhagen, Denmark Univ Paris 05, Fac Med, Serv Hosp Univ, Hop St Anne, Paris, France Univ Autonoma Barcelona, Dept Psicol Clin & Salut, E-08193 Barcelona, Spain St Pere Claver Fundacio Sanitaria, Dept Salut Mental, Barcelona, Spain Univ N Carolina, Dept Psychol, Greensboro, NC 27412 USA CIBERSAM, Spanish Mental Hlth Res Network, Barcelona, Spain Universidade Federal de São Paulo, Dept Psychiat, PRISMA Early Intervent Program, São Paulo, Brazil Univ Belgrade, Sch Med, Beograd, Serbia Universidade Federal de São Paulo, Dept Psychiat, PRISMA Early Intervent Program, São Paulo, Brazil European Community: HEALTH-F2-2009-241909 Web of Science

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.