"); } } if(responsiveDesign==1){ //Page is responsive design, check if it is an article page if($("[data-widget-def='UX3articleContent']").length!=0){ //Its an article page, disable the sticky sidebar disableStickySidebar = 1; } } if(disableStickySidebar==0){ //Check for disableStickySidebar in Querystring disableStickySidebar = gpt_GetQuerystring('disableStickySidebar',0); } if(disableStickySidebar!=0){ //Disable the sticky leaderbard //Check for page flag, if it does not exist, create it. if($('#disableStickySidebar').length==0){ $("body").append("
'); } googletag.cmd.push(function() { var gptAdSlots = []; //*********************************************** //Start Define Size mapping based on client Viewport //*********************************************** var gptLeaderboardSizeMapping = googletag.sizeMapping(). addSize([768, 0], [[728, 90]]). // Leaderboard addSize([0, 0], [[320, 50], [300, 50]]). // Mobile Leaderboard build(); var gptSideBarSizeMapping = googletag.sizeMapping(). addSize([1140, 800], [[160, 600], [300, 250]]). // SkyScraper - Desktop (Require min 800 vertical), Fall back to Boombox addSize([1140, 450], [[300, 250]]). // BoomBox - Desktop (Require min 450 vertical) addSize([0, 0], []). // Phone-Tablet build(); var gptSideBarNotResponsiveSizeMapping = googletag.sizeMapping(). addSize([1140, 800], [[160, 600]]). // SkyScraper - Desktop (Require min 800 vertical) addSize([0, 0], []). // Phone-Tablet build(); var gptSideBarNotStickySizeMapping = googletag.sizeMapping(). addSize([1140, 800], [[160, 600], [300, 250]]). // SkyScraper Not Sticky (Require min 800 vertical), Fall back to Boombox addSize([1140, 450], [[300, 250]]). // BoomBox Not Sticky (Require min 450 vertical) addSize([0, 0], []). // Phone-Tablet build(); //*********************************************** //End Define Size mapping based on client Viewport //*********************************************** //*********************************************** //Start detection for ad slots on page //*********************************************** $(".gpt-ad").each(function( index ) { var gptSite = GPT_CheckForNULL($('#gptSite').val()); var gptPage = ''; var adSizeMapping=''; var adId; var gptPOS; var gptMasterPage = GPT_CheckForNULL($('#gptPage').val()); if (gptSite == null) { gptSite = GPT_CheckForNULL($('#gptAltSite').val()); if (gptSite == null) { gptSite = GPT_CheckForNULL($(this).data('site')); } } if (gptSite == null) { gptSite = GPT_CheckForNULL($('#gptDefaultSite').val()); } if(gptSite!=null){ adId = 'gpt-ad-' + index + 1; gptPOS = parseInt($(this).data('pos')) || -1; if(gptPOS == -1){ gptPOS = index + 1; } if (gptMasterPage != null) { gptPage = '/' + gptMasterPage; } else { gptPage = GPT_CheckForNULL($(this).data('page')); if (gptPage != null) { gptPage = '/' + gptPage; } else { gptPage = ''; } } //Determine sizemapping based on data-adsize switch($(this).data('adsize')) { case 'cell-leaderboard': adSizeMapping = gptLeaderboardSizeMapping; if(gptPOS==1){ $(this).addClass('GPT-Leaderboard-Cell'); } break; case 'leaderboard': adSizeMapping = gptLeaderboardSizeMapping; $(this).addClass('GPT-Leaderboard'); break; case 'boombox': adSizeMapping = gptBoomBoxSizeMapping; break; case 'skyscraper': if($(this).hasClass("disableStickySidebar")){ adSizeMapping = gptSideBarNotStickySizeMapping; } else{ $(this).addClass('GPT-StickySideBar'); adSizeMapping = gptSideBarSizeMapping; } break; case 'skyscrapernotresponsive': adSizeMapping = gptSideBarNotResponsiveSizeMapping; break; } } //Ignore any invalid adsizes that could be on the page if(adSizeMapping!='') { $(this).addClass('gpt-ad-defined'); $(this).attr('id',adId); gptAdSlots[index] = googletag.defineSlot('/6053/els.' + gptSite + gptPage, [], adId).defineSizeMapping(adSizeMapping).addService(googletag.pubads()).setTargeting("pos", gptPOS); } else { $(this).remove(); } }); //*********************************************** //End detection for ad slots on page //*********************************************** //*********************************************** //Start page level targeting //*********************************************** gpt_Target("LoggedIn"); gpt_Target("PII"); //Check for DFP Test gpt_GetDFPTestId(); //Check for Additional Targeting gpt_GetAdditionalTargeting() //*********************************************** //End page level targeting //*********************************************** //Enable google dfp services googletag.pubads().enableSingleRequest(); googletag.pubads().collapseEmptyDivs(); googletag.enableServices(); //Add Listener for Leaderboard googletag.pubads().addEventListener('slotRenderEnded', function(event) { if (!event.isEmpty) { $('#' + event.slot.getSlotElementId()).closest(".GPT-ad-placeholder").css("display", "block"); //Sticky LeaderBoard JBS if ($('#' + event.slot.getSlotElementId()).hasClass("GPT-Leaderboard")) { if($('#disableStickyLeaderboard').length==0){ $('body').addClass("hasLeaderboard"); // INJECT SOME CSS FOR STICKY LEADERBOARD // THIS INCLUDES CHANGING THE TOP OF THE STICKY HEADER #jbs-fixed-hdr $("body").append("
"); setTimeout(handleStickyLeaderboard, 8000); } } //Sticky LeaderBoard Cell if ($('#' + event.slot.getSlotElementId()).hasClass("GPT-Leaderboard-Cell")) { if($('#disableStickyLeaderboard').length==0){ $("body").append('
'); $("div.cell-top-head").attr("style","display:block !important;"); $("body").append(""); var tmp; tmp = $(".article.enhanced .tab-nav").attr("style"); tmp = "top:110px;" + tmp; $(".article.enhanced .tab-nav").removeAttr("style"); $(".article.enhanced .tab-nav").attr("style",tmp); tmp = $(".article.enhanced #fixedPane").attr("style"); tmp = "top:148px;" + tmp; $(".article.enhanced #fixedPane").removeAttr("style"); $(".article.enhanced #fixedPane").attr("style",tmp); setTimeout(handleStickyLeaderboard_CELL, 8000); } // THE FOLLOWING MAKES SURE THAT THE FIGURES PANE POPULATES // (there might be a bug on the live site) $("li.showFullText a").click(); } //Sticky SideBar if ($('#' + event.slot.getSlotElementId()).hasClass("GPT-StickySideBar")){ if($('#disableStickySidebar').length==0){ enableStickySideBar(); } } } }); //Populate Defined Ad Slots $(".gpt-ad-defined").each(function( index ) { var adId = $(this).attr('id'); googletag.cmd.push(function() {googletag.display(adId);}); }); }); }
Nathan A Gillespie
AffiliationsGenetic Epidemiology, Statistical Genetics, and Translational Neurogenomics Laboratories, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
Department of Psychiatry, Virginia Institute for Psychiatric and Behavior Genetics, Virginia Commonwealth University, Richmond, VA, USA
Search for articles by this authorJorien L Treur
AffiliationsDepartment of Psychiatry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands
Search for articles by this authorKarin J H Verweij
AffiliationsDepartment of Psychiatry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands
Search for articles by this authorMarta Di Forti and colleagues
1The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study.
claim that the frequency of cannabis use and cannabis potency are responsible for substantial variation in the incidence of psychotic disorders. The authors assume that cannabis causes psychosis or psychotic symptoms without acknowledging compelling, alternative hypotheses.
2An overview of systematic reviews on cannabis and psychosis: discussing apparently conflicting results.
Most reports examining associations between cannabis and psychosis have been unable to adjust for confounding that arises from correlated genetic and environmental individual differences. This oversight includes the common omission of appropriate methods for resolving causality (eg, random assignment to case and control conditions, discordant twin pairs, propensity score matching, or recently advanced genome-based restricted maximum likelihood methods). Findings of our own and others illustrate that cannabis use might be higher among individuals with a genetic liability that predisposes such individuals to cannabis use and the development of psychosis or psychotic disorders. Giordano and colleagues'
3The association between cannabis abuse and subsequent schizophrenia: a Swedish national co-relative control study.
co-relative case-control design, which extrapolated data for monozygotic twin pairs, reported that a large portion of the association between cannabis abuse and schizophrenia was not causal, but instead confounded by shared familial factors. Despite increases in the prevalence of cannabis use over a 30-year period in Australia, Degenhardt and colleagues
4Testing hypotheses about the relationship between cannabis use and psychosis.
found no evidence of any notable increase in schizophrenia. Based on our recent meta-analysis of the largest genome-wide association study of lifetime cannabis use to date (n=184 765), we estimated a genome-wide genetic correlation of 0·25 (SE 0·03, p<0·0001) with schizophrenia risk, indicating that genetic risk factors for cannabis use and schizophrenia are positively correlated.
5GWAS of lifetime cannabis use reveals new risk loci, genetic overlap with psychiatric traits, and a causal influence of schizophrenia.
This correlation could be explained by pleiotropic, causal, or reverse causal mechanisms. Mendelian randomisation is an approach that uses genetic variants associated with a modifiable exposure to estimate the causal relationship between variables. In our meta-analysis, we applied bidirectional mendelian randomisation and found a consistent pattern of evidence supporting a causal effect of schizophrenia risk on lifetime cannabis use.
5GWAS of lifetime cannabis use reveals new risk loci, genetic overlap with psychiatric traits, and a causal influence of schizophrenia.
By contrast, we found little evidence for any causal effect of cannabis use on schizophrenia risk. We acknowledged the lower power of the instrumental variable for lifetime cannabis use,
5GWAS of lifetime cannabis use reveals new risk loci, genetic overlap with psychiatric traits, and a causal influence of schizophrenia.
and our analyses were not based on cannabis use frequency or potency. Nevertheless, our findings strongly suggested that associations between measures of cannabis use and psychosis or psychotic disorders are far more nuanced than Di Forti and colleagues assume. In addition to correlated genetic liabilities, indirect and bidirectional processes are likely to affect the associations between cannabis use, misuse, and psychotic disorders. By not acknowledging the alternative, compelling and plausible mechanisms,
3The association between cannabis abuse and subsequent schizophrenia: a Swedish national co-relative control study.
Di Forti and colleagues' conclusion regarding the harmful effect of high-potency cannabis use on mental health is likely to be overestimated.
This online publication has been corrected. The corrected version first appeared at thelancet.com/psychiatry on June 7, 2019
We declare no competing interests.
The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study.
Lancet Psychiatry. 2019;
6 : 427-436An overview of systematic reviews on cannabis and psychosis: discussing apparently conflicting results.
Drug Alcohol Rev. 2010;
29 : 304-317The association between cannabis abuse and subsequent schizophrenia: a Swedish national co-relative control study.
Psychol Med. 2015;
45 : 407-414Testing hypotheses about the relationship between cannabis use and psychosis.
Drug Alcohol Depend. 2003;
71 : 37GWAS of lifetime cannabis use reveals new risk loci, genetic overlap with psychiatric traits, and a causal influence of schizophrenia.
Nat Neurosci. 2018;
21 : 1161-1170DOI: https://doi.org/10.1016/S2215-0366(19)30174-9
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