{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,21]],"date-time":"2026-10-21T14:41:50Z","timestamp":1792593710303,"version":"4.5.0"},"reference-count":30,"publisher":"American Medical Association (AMA)","issue":"9","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA Netw Open"],"abstract":"Importance<\/jats:title>Prior research suggests that the legalization of recreational cannabis is associated with increases in cannabis hyperemesis syndrome (CHS), but it is unclear how cannabis commercialization (ie, greater retail store access as well as increased variety and potency of cannabis products) may be associated with these changes.<\/jats:p><\/jats:sec>Objectives<\/jats:title>To examine changes in the number and characteristics of CHS emergency department (ED) visits from before to after legalization of cannabis in Ontario, Canada.<\/jats:p><\/jats:sec>Design, Setting, and Participants<\/jats:title>This repeated cross-sectional study used interrupted time-series analyses to examine immediate and gradual changes in ED visits for CHS in Ontario, Canada, during 3 time periods: prelegalization (January 2014-September 2018), legalization with product and retail store restrictions (October 2018-February 2020), and commercialization with new products and expanded stores, which coincided with the COVID-19 pandemic (March 2020-June 2021). Data were obtained from routinely collected and linked health administrative databases. All individuals aged at least 15 years and who were eligible for Ontario\u2019s Universal Health Coverage were included. Data were analyzed between March and July 2022.<\/jats:p><\/jats:sec>Main Outcomes and Measures<\/jats:title>Monthly counts of ED visits for CHS per capita.<\/jats:p><\/jats:sec>Results<\/jats:title>There were 12\u202f866 ED visits for CHS from 8140 individuals during the study. Overall, the mean (SD) age was 27.4 (10.5) years, with 2834 individuals (34.8%) aged 19 to 24 years, 4163 (51.5%) females, and 1353 individuals (16.6%) with a mental health ED visit or hospitalization in the 2 years before their first CHS ED visit. Nearly 10% of visits (1135 visits [8.8%]) led to hospital admissions. Monthly rates of CHS ED visits increased 13-fold during the 7.5-year study period, from 0.26 visits per 100\u202f000 population in January 2014 to 3.43 visits per 100\u202f000 population in June 2021. Legalization was not associated with an immediate or gradual change in rates of ED visits for CHS; however, commercialization during the COVID-19 pandemic period was associated with an immediate increase in rates of CHS ED visits (incidence rate ratio [IRR], 1.49; 95% CI, 1.31-1.70). During commercialization, rates of CHS ED visits increased more in women (IRR, 1.49; 95% CI, 1.16-1.92) and individuals older than the legal age of cannabis purchase (eg, age 19-24 years: IRR, 1.60; 95% CI, 1.19-2.16) than men (IRR, 1.08; 95% CI, 0.85-1.37) and individuals younger than the legal age of purchase (IRR, 0.78; 95% CI, 0.42-1.45).<\/jats:p><\/jats:sec>Conclusions and Relevance<\/jats:title>This cross-sectional study found large increases in CHS ED visits during the period of time when the market commercialized and the COVID-19 pandemic occurred. Greater awareness of CHS symptoms by ED staff in regions where legal commercialized cannabis markets exist is indicated.<\/jats:p><\/jats:sec>","DOI":"10.1001\/jamanetworkopen.2022.31937","type":"journal-article","created":{"date-parts":[[2022,9,16]],"date-time":"2022-09-16T15:31:55Z","timestamp":1663342315000},"page":"e2231937","source":"Crossref","is-referenced-by-count":57,"title":["Changes in Emergency Department Visits for Cannabis Hyperemesis Syndrome Following Recreational Cannabis Legalization and Subsequent Commercialization in Ontario, Canada"],"prefix":"10.1001","volume":"5","author":[{"given":"Daniel Thomas","family":"Myran","sequence":"first","affiliation":[{"name":"Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada"},{"name":"Department of Family Medicine, University of Ottawa, Ottawa, Ontario, Canada"},{"name":"ICES Ottawa, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rhiannon","family":"Roberts","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Pugliese","sequence":"additional","affiliation":[{"name":"ICES Ottawa, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monica","family":"Taljaard","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada"},{"name":"School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter","family":"Tanuseputro","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada"},{"name":"ICES Ottawa, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada"},{"name":"Bruy\u00e8re Research Institute, Ottawa, Ontario, Canada"},{"name":"Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rosalie Liccardo","family":"Pacula","sequence":"additional","affiliation":[{"name":"Sol Price School of Public Policy, Schaeffer Center for Health Policy & Economics, University of Southern California, Los Angeles"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"10","published-online":{"date-parts":[[2022,9,16]]},"reference":[{"issue":"8","key":"zoi220912r3","doi-asserted-by":"publisher","first-page":"777","DOI":"10.1001\/jamapsychiatry.2020.0339","article-title":"Will legalization and commercialization of cannabis use increase the incidence and prevalence of psychosis?","volume":"77","author":"Murray","year":"2020","journal-title":"JAMA Psychiatry"},{"key":"zoi220912r4","doi-asserted-by":"publisher","first-page":"833","DOI":"10.3389\/fpsyg.2020.00833","article-title":"Unraveling the intoxicating and therapeutic effects of cannabis ingredients on psychosis and cognition.","volume":"11","author":"Colizzi","year":"2020","journal-title":"Front Psychol"},{"issue":"10208","key":"zoi220912r5","doi-asserted-by":"publisher","first-page":"1580","DOI":"10.1016\/S0140-6736(19)31789-1","article-title":"Public health implications of legalising the production and sale of cannabis for medicinal and recreational use.","volume":"394","author":"Hall","year":"2019","journal-title":"Lancet"},{"issue":"23","key":"zoi220912r6","doi-asserted-by":"publisher","first-page":"2219","DOI":"10.1056\/NEJMra1402309","article-title":"Adverse health effects of marijuana use.","volume":"370","author":"Volkow","year":"2014","journal-title":"N Engl J Med"},{"issue":"6","key":"zoi220912r7","doi-asserted-by":"publisher","first-page":"1380","DOI":"10.1053\/j.gastro.2016.02.011","article-title":"Gastroduodenal disorders.","volume":"150","author":"Stanghellini","year":"2016","journal-title":"Gastroenterology"},{"issue":"9","key":"zoi220912r8","doi-asserted-by":"publisher","DOI":"10.1001\/jamanetworkopen.2021.25275","article-title":"Growth in recreational cannabis markets and burden on emergency departments.","volume":"4","author":"Mycyk","year":"2021","journal-title":"JAMA Netw Open"},{"issue":"9","key":"zoi220912r9","doi-asserted-by":"publisher","DOI":"10.1001\/jamanetworkopen.2021.25063","article-title":"Changes in emergency department encounters for vomiting after cannabis legalization in Colorado.","volume":"4","author":"Wang","year":"2021","journal-title":"JAMA Netw Open"},{"issue":"6","key":"zoi220912r10","doi-asserted-by":"publisher","first-page":"776","DOI":"10.1017\/cem.2020.384","article-title":"Clearing the air: a study of cannabis-related presentations to urban Alberta emergency departments following legalization.","volume":"22","author":"Yeung","year":"2020","journal-title":"CJEM"},{"issue":"6","key":"zoi220912r11","doi-asserted-by":"publisher","first-page":"694","DOI":"10.1111\/acem.12655","article-title":"Cyclic vomiting presentations following marijuana liberalization in Colorado.","volume":"22","author":"Kim","year":"2015","journal-title":"Acad Emerg Med"},{"issue":"4","key":"zoi220912r12","doi-asserted-by":"publisher","DOI":"10.1542\/peds.2020-045922","article-title":"Emergency department pediatric visits in Alberta for cannabis after legalization.","volume":"148","author":"Yeung","year":"2021","journal-title":"Pediatrics"},{"issue":"3","key":"zoi220912r14","doi-asserted-by":"publisher","first-page":"E454","DOI":"10.9778\/cmajo.20190012","article-title":"Access to cannabis retail stores across Canada 6 months following legalization: a descriptive study.","volume":"7","author":"Myran","year":"2019","journal-title":"CMAJ Open"},{"issue":"2","key":"zoi220912r15","doi-asserted-by":"publisher","first-page":"377","DOI":"10.1111\/dar.v41.2","article-title":"How has access to legal cannabis changed over time: an analysis of the cannabis retail market in Canada 2 years following the legalisation of recreational cannabis.","volume":"41","author":"Myran","year":"2022","journal-title":"Drug Alcohol Rev"},{"issue":"7","key":"zoi220912r16","doi-asserted-by":"publisher","first-page":"1952","DOI":"10.1111\/add.v117.7","article-title":"The association between recreational cannabis legalization, commercialization and cannabis-attributable emergency department visits in Ontario, Canada: an interrupted time-series analysis.","volume":"117","author":"Myran","year":"2022","journal-title":"Addiction"},{"issue":"10312","key":"zoi220912r17","doi-asserted-by":"publisher","first-page":"1700","DOI":"10.1016\/S0140-6736(21)02143-7","article-title":"Global prevalence and burden of depressive and anxiety disorders in 204 countries and territories in 2020 due to the COVID-19 pandemic.","volume":"398","author":"Santomauro","year":"2021","journal-title":"Lancet"},{"issue":"4","key":"zoi220912r19","doi-asserted-by":"publisher","first-page":"550","DOI":"10.1017\/cem.2017.381","article-title":"Cannabinoid hyperemesis syndrome presentation to the emergency department: a two-year multicentre retrospective chart review in a major urban area.","volume":"20","author":"Hernandez","year":"2018","journal-title":"CJEM"},{"key":"zoi220912r20","doi-asserted-by":"publisher","first-page":"l4336","DOI":"10.1136\/bmj.l4336","article-title":"Cannabinoid hyperemesis syndrome.","volume":"366","author":"Chocron","year":"2019","journal-title":"BMJ"},{"issue":"S2","key":"zoi220912r22","doi-asserted-by":"publisher","first-page":"S18","DOI":"10.1017\/cem.2017.365","article-title":"Revisions to the Canadian Emergency Department Triage and Acuity Scale (CTAS) guidelines 2016.","volume":"19","author":"Bullard","year":"2017","journal-title":"CJEM"},{"issue":"2","key":"zoi220912r24","doi-asserted-by":"publisher","first-page":"143","DOI":"10.1016\/j.jclinepi.2008.08.007","article-title":"Methods for estimating confidence intervals in interrupted time series analyses of health interventions.","volume":"62","author":"Zhang","year":"2009","journal-title":"J Clin Epidemiol"},{"issue":"4","key":"zoi220912r25","doi-asserted-by":"publisher","first-page":"E988","DOI":"10.9778\/cmajo.20210100","article-title":"Acute mental health service use following onset of the COVID-19 pandemic in Ontario, Canada: a trend analysis.","volume":"9","author":"Saunders","year":"2021","journal-title":"CMAJ Open"},{"issue":"5","key":"zoi220912r28","doi-asserted-by":"publisher","first-page":"1131","DOI":"10.1111\/dar.v41.5","article-title":"Interrupted time series analysis of Canadian legal cannabis sales during the COVID-19 pandemic.","volume":"41","author":"Armstrong","year":"2022","journal-title":"Drug Alcohol Rev"},{"key":"zoi220912r1","unstructured":"Substance Abuse and Mental Health Services Administration. 2020 National Survey on Drug Use and Health: Table 1.1A: types of illicit drug use in lifetime, past year, and past month: among people aged 12 or older; numbers in thousands, 2019 and 2020. Accessed March 17, 2022. https:\/\/www.samhsa.gov\/data\/sites\/default\/files\/reports\/rpt35323\/NSDUHDetailedTabs2020\/NSDUHDetailedTabs2020\/NSDUHDetTabsSect1pe2020.htm"},{"key":"zoi220912r2","unstructured":"Health Canada. Statistic\u2019s Canada. Canadian Alcohol and Drugs Survey (CADS): Summary of Results for 2019.; 2021. Accessed March 17, 2022. https:\/\/www.canada.ca\/en\/health-canada\/services\/canadian-alcohol-drugs-survey\/2019-summary.html#a4"},{"key":"zoi220912r13","unstructured":"Parliament of Canada. Cannabis Act (SC 2018, c. 16). Accessed March 17, 2022. https:\/\/laws-lois.justice.gc.ca\/eng\/acts\/c-24.5\/"},{"key":"zoi220912r18","unstructured":"ICES. Mental health and addictions dashboard: Ontario mental health systems reporting\u2014overview of monthly mental health and addictions trends in Ontario, January 2017\u2013June 2021. Accessed April 7, 2022. https:\/\/www.ices.on.ca\/Research\/Research-programs\/Mental-Health-and-Addictions\/MHA-Dashboard"},{"key":"zoi220912r21","unstructured":"MHASEF Research Team. Mental health and addictions system performance in Ontario: a baseline scorecard. Accessed March 21, 2022. https:\/\/www.ices.on.ca\/Publications\/Atlases-and-Reports\/2018\/MHASEF"},{"key":"zoi220912r23","unstructured":"Statistics Canada. Population centre and rural area classification 2016. Accessed March 21, 2022. https:\/\/www.statcan.gc.ca\/en\/subjects\/standard\/pcrac\/2016\/introduction"},{"key":"zoi220912r26","unstructured":"Canadian Institute for Substance Use Research. Regulated cannabis sales in BC: 2018-2020. Accessed March 21, 2022. https:\/\/www.uvic.ca\/research\/centres\/cisur\/stats\/cannabis\/"},{"key":"zoi220912r27","unstructured":"Ontario Cannabis Store. A quarterly review: July 1\u2013September 30, 2021. Accessed March 21, 2022. https:\/\/cdn.shopify.com\/s\/files\/1\/2636\/1928\/files\/OCS-InsightsReport_Q2-2021_149b7580-b083-4cc0-8c92-bf2b3b59cb7f.pdf?v=1639588082"},{"key":"zoi220912r29","unstructured":"Hango? D, Larochelle-C\u00f4t\u00e9? S. Association between the frequency of cannabis use and selected social indicators. Accessed March 21, 2022. https:\/\/publications.gc.ca\/site\/eng\/9.856099\/publication.html"},{"key":"zoi220912r30","unstructured":"Health Quality Ontario. Under pressure: emergency department performance in Ontario. Accessed April 24, 2022. http:\/\/www.hqontario.ca\/Portals\/0\/documents\/system-performance\/under-pressure-report-en.pdf"}],"container-title":["JAMA Network Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/jamanetwork.com\/journals\/jamanetworkopen\/articlepdf\/2796355\/myran_2022_oi_220912_1662670428.75113.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,9,16]],"date-time":"2022-09-16T15:32:00Z","timestamp":1663342320000},"score":1,"resource":{"primary":{"URL":"https:\/\/jamanetwork.com\/journals\/jamanetworkopen\/fullarticle\/2796355"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,16]]},"references-count":30,"journal-issue":{"issue":"9","published-print":{"date-parts":[[2022,9,1]]}},"URL":"https:\/\/doi.org\/10.1001\/jamanetworkopen.2022.31937","relation":{},"ISSN":["2574-3805"],"issn-type":[{"value":"2574-3805","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,9,16]]}}}