The association between physical availability of cannabis retail outlets and frequent cannabis use and related health harms: a systematic review.

An increasing number of regions have or are considering legalising the sale of cannabis for adult use. Experience from tobacco and alcohol regulation has found that greater access to physical retail stores is positively associated with increased substance use and harm. Whether this association exists for cannabis is unclear. We completed a systematic review examining the association between cannabis retail store access and adverse health outcomes. We identified articles up until July 20, 2023 by searching four databases. We included studies examining the association between measures of cannabis store access and adverse outcomes: frequent or problematic cannabis use, healthcare encounters due to cannabis use (e.g., cannabis-induced psychosis), and healthcare encounters potentially related to cannabis (e.g., self-harm episodes). Results were compared by study design type, retail access measure, and by subgroups including: children, adolescents, young adults, adults, and pregnant individuals. This review was registered with PROSPERO (CRD42021281788). The search generated 5750 citations of which we included 32 studies containing 44 unique primary analyses (unique retail measure and outcome pairs). Studies come from 4 countries (United States, Canada, Netherlands and Uruguay). Among the included analyses, there were consistent positive associations between greater cannabis retail access and 1) increased healthcare service use or poison control calls directly due to cannabis (10/12 analyses; 83%) (2) increased cannabis use and cannabis-related hospitalization during pregnancy (4/4; 100%) and 3) frequent cannabis use in adults and young adults (7/11; 64%). There was no consistent positive association between greater cannabis retail and increased frequent cannabis use in adolescents (1/4; 25%), healthcare service use potentially related to cannabis (2/6; 33%) or increased adverse neonatal birth outcomes (2/7; 26.8%). There is a positive association between greater cannabis store access and increases in cannabis harm. In countries with legal cannabis, retail restrictions may reduce use and harm. Funding: Canadian Centre on Substance Use and Addiction (CCSA).

The association between recreational cannabis legalization, commercialization and cannabis-attributable emergency department visits in Ontario, Canada: an interrupted time-series analysis.

BACKGROUND AND AIMS: Recreational cannabis was legalized in Canada in October 2018. Initially, the Government of Ontario (Canada's largest province) placed strict limits on the number of cannabis retail stores before later removing these limits. This study measured changes in cannabis-attributable emergency department (ED) visits over time, corresponding to different regulatory periods. DESIGN: Interrupted time-series design using population-level data. Two policy periods were considered; recreational cannabis legalization with strict store restrictions (RCL, 17 months) and legalization with no store restrictions [recreational cannabis commercialization (RCC), 15 months] which coincided with the COVID-19 pandemic. Segmented Poisson regression models were used to examine immediate and gradual effects in each policy period. SETTING: Ontario, Canada. PARTICIPANTS: All individuals aged 15-105 years (n = 13.8 million) between January 2016 and May 2021. MEASUREMENTS: Monthly counts of cannabis-attributable ED visits per capita and per all-cause ED visits in individuals aged 15+ (adults) and 15-24 (young adults) years. FINDINGS: We observed a significant trend of increasing cannabis-attributable ED visits pre-legalization. RCL was associated with a significant immediate increase of 12% [incident rate ratio (IRR) = 1.12, 95% confidence interval (CI) = 1.02-1.23] in rates of cannabis-attributable ED visits followed by significant attenuation of the pre-legalization slope (monthly slope change IRR = 0.98, 95% CI = 0.97-0.99). RCC and COVID-19 were associated with immediate significant increases of 22% (IRR = 1.22, 95% CI = 1.09-1.37) and 17% (IRR = 1.17, 95% CI = 1.00-1.37) in rates of cannabis-attributable visits and the proportion of all-cause ED visits attributable to cannabis, respectively, with insignificant increases in monthly slopes. Similar patterns were observed in young adults. CONCLUSIONS: In Ontario, Canada, cannabis-attributable emergency department visits stopped increasing over time following recreational cannabis legalization with strict retail controls but then increased during a period coinciding with cannabis commercialization and the COVID-19 pandemic.

Correlates of driving after cannabis use in high school students.

Driving under the influence of cannabis is a growing public health concern among young people. This study assessed the prevalence of cannabis-impaired driving and its related sociodemographic, psychological, and knowledge-based correlates among Canadian adolescents. The sample for this study were drawn from the 2017 Ontario Student Health and Drug Use Survey (OSDUHS), consisting of high school students with valid driver's licenses (mean age = 16.8, SD = 0.71) who were asked about their driving behaviors, drug use, and attitudes regarding cannabis use (N = 1161). A multivariable logistic regression model was performed to determine the strongest correlates of driving after cannabis use. The prevalence of past-year driving within an hour of cannabis use was 10.3% (95% CI: 7.8,13.5). In the final multivariable model, probable cannabis dependence (OR = 12.7, 95%CI: 3.4,47.7), low perceived risk of cannabis use (OR = 5.3, 95%CI: 2.5,11.1), pro-legalization attitudes, (OR = 4.3, 95%CI: 2.0,9.1) and male gender (OR = 2.6, 95%CI: 1.5,4.5) were significantly associated with driving under the influence of cannabis. Other correlates of driving after cannabis user were risky driving behaviors, including past-year texting and driving and driving after alcohol use. There are various correlates of driving under the influence of cannabis, including attitudes related to cannabis which may be amenable to intervention. Future efforts should continue to monitor the prevalence of cannabis-impaired driving in this population and determine whether changes in students' attitudes surrounding cannabis are linked to behavioural changes.