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Background/Aims: The COVID‐19 pandemic has significantly impacted face‐to‐face research. This has propelled ideas and plans for more remote styles of research and provided new perspectives on conducting research. This paper aimed to identify challenges specific to conducting remote forms of experimental addiction research, although some of these challenges apply to all types of addiction research. Argument The impact of the COVID‐19 pandemic has led to important lessons for future addiction research. Although remote research has been conducted for decades, little experimental research has been performed remotely. To do so require a new perspective on what research questions we can ask and could also enable preferential capture of those who may be more reluctant to engage in research based in clinical settings. There may, however, be crucial factors that will compromise this process. We illustrate our argument with three real‐world, ongoing case studies centred on gambling behaviour, opioid overdose, and cannabinoid psychopharmacology. We highlight the obstacles to overcome to enable more remote methods of study. Conclusions: The future of experimental research and, more generally, addiction research, will be shaped by the pandemic and may result in advantages, such as reaching different populations and conducting addiction research in more naturalistic settings. [ABSTRACT FROM AUTHOR]

Background and aim: In Uruguay, residents age 18 and older seeking legal cannabis must register with the government and choose one of three supply mechanisms: self‐cultivation, non‐profit cannabis clubs or pharmacies. This is the first paper to measure the association between type of legal cannabis supply mechanism and traffic crashes involving injuries. Design Ecological study using ordinary least squares regression to examine how department‐level variation in registrations (overall and by type) is associated with traffic crashes involving injuries. Setting: Uruguay. Cases 532 department‐quarters. Measurements Quarterly cannabis registration counts at the department level and incident‐level traffic crash data were obtained from government agencies. The analyses controlled for department‐level economic and demographic characteristics and, as a robustness check, we included traffic violations involving alcohol for departments reporting this information. Department‐level data on crashes, registrations and alcohol violations were denominated by the number of residents ages 18 and older. Findings From 2013 to 2019, the average number of registrations at the department‐quarter level per 10 000 residents age 18 and older for self‐cultivation, club membership and pharmacy purchasing were 17.7 (SD = 16.8), 3.6 (SD = 8.6), and 25.1 (SD = 50.4), respectively. In our multivariate regression analyses, we did not find a statistically significant association between the total number of registrations and traffic crashes with injuries (β = −0.007; P = 0.398; 95% CI = −0.023, 0.01). Analyses focused on the specific supply mechanisms found a consistent, positive and statistically significant association between the number of individuals registered as self‐cultivators and the number of traffic crashes with injuries (β = 0.194; P = 0.008; 95% CI = 0.058, 0.329). Associations for other supply mechanisms were inconsistent across the various model specifications. Conclusions: In Uruguay, the number of people allowed to self‐cultivate cannabis is positively associated with traffic crashes involving injuries. Individual‐level analyses are needed to assess better the factors underlying this association. [ABSTRACT FROM AUTHOR]

Background and aim: New Zealand has recently legalized medicinal cannabis and has explored the possibility of legalizing large‐scale recreational cannabis supply. In the process, concerns have emerged regarding whether corporations involved in the large‐scale production and sale of legalized cannabis will invest in tactics of influence with policymakers and the public. This paper aimed to examine the various ways a legalized cannabis industry could seek to influence governments and the public in the New Zealand reform context. Method: Based on the study of industry tactics with alcohol, tobacco and gambling, we applied a three‐chain model of industry influence that breaks tactics into the 'public good', 'knowledge' and 'political' chains. Results: Exploratory analysis of the nascent cannabis industry's activity in New Zealand provided signs of industry influence strategies related to all three chains. The medicinal cannabis industry has associated the establishment of a legal cannabis sector with regional economic development and employment, supported lobbying for recreational law reform, funded NGOs involved in lobbying for law reform, established research partnerships with universities, invited ex‐politicians on advisory boards, and participated in government public sector partnerships. Conclusion: There is emerging evidence that the legal cannabis industry is using strategies to influence the regulatory environment in New Zealand. [ABSTRACT FROM AUTHOR]

Background: Nationally representative data of cannabis–tobacco co‐use have shown that these substances are closely entwined and have significant adverse health consequences, although population‐level harms of co‐use are largely unknown. Current epidemiological research does not assess co‐use in a manner that has yielded the necessary data to draw conclusions regarding health effects. This has given rise to a hidden population of co‐users who go under‐served. Therefore, this paper has two aims: (1) to review new challenges in the collection of co‐use data due to rapidly changing regulations of cannabis and nicotine products and (2) to provide recommendations for the terminology and assessment of co‐use. Argument We argue that: (1) the prevalence of co‐use is not being assessed accurately at a population level and (2) changes in legalization have created novel challenges, but without proper monitoring the impact on co‐use will go undetected. We propose a three‐level tiered set of recommendations for co‐use assessments, which includes assessments of cannabis, tobacco and co‐use metrics ranging from least burdensome (self‐report of co‐administered products) to most burdensome (assays, event‐level data). Conclusions: We propose that clinical studies begin to incorporate cannabis–tobacco co‐use assessments to justify better their inclusion in clinical trials and national surveillance surveys. Integration of co‐use assessments will aid in understanding the true impact on co‐use of the changing cannabis and tobacco/nicotine regulatory environments. Co‐use is prevalent and problematic, and the ability to make conclusions about its health outcomes is hindered by lack of nuance in data collection. If you do not measure it, you cannot manage it. [ABSTRACT FROM AUTHOR]

Abstract: During the early 1970s Denise Kandel and her colleagues documented an ‘invariant sequence’ in initiation of drug use: starting with alcohol and tobacco, progressing to cannabis and then to other illicit, or ‘harder’ drugs. This observation, which became known as the ‘gateway sequence’ of drug use, has been influential in policy debates but remains highly contentious, with the area of greatest controversy focusing upon whether cannabis use increases risk causally for initiation of other illicit drugs. While numerous studies have replicated Kandel's initial findings (sequence of onset) and reported that associations between cannabis use and the use of other illicit drugs remain after controlling for potentially confounding factors, the mechanisms underlying these observed associations remain hotly debated. In particular, it is possible that the observed associations are non‐causal but reflect the influence of confounding factors which influence both early‐onset drug use and subsequent progressions. However, research employing a range of techniques to address this issue has been unable to discount the possibility that associations between earlier and subsequent drug use reflect causal processes. This paper reviews Kandel's ongoing contributions to this field, which span 45 years, and discusses both the influence of her work and the controversy that it has aroused. [ABSTRACT FROM AUTHOR]

Abstract: A major impediment to any nation abandoning the policy of drug prohibition has been the fact that international drug treaties to which the majority of United Nations (UN) member states are signatory prohibit the non‐medical use of amphetamines, cannabis, cocaine and heroin. The future of these treaties is now uncertain because of decisions by Uruguay, eight US states and Canada to legalize cannabis use. This paper: (1) provides a brief account of the international drug control treaties; (2) outlines the major criticisms of the treaties; (3) analyses critically proposals for treaty reform; and (4) provides a personal view on policies that nation states could adopt to minimize the harms from the use of cannabis, party drugs and hallucinogens, opioids, stimulants and new psychoactive substances. It is argued that: a major risk of cannabis legalization in the United States is promotion of heavy use and increased harm by a weakly regulated industry; some cautious national experiments with the regulation of party drugs and hallucinogens would be informative; a strong case remains for prohibiting the nonmedical use of opioids while mitigating the adverse effects that this policy has on opioid‐dependent people; stimulant legalization will probably increase problem use but prohibition is difficult to enforce, highlighting the urgency of finding better ways to reduce demand for these drugs and respond to problem users; and that it is unclear what the best approach is to reducing possible harms that may arise from the use of new psychoactive substances. [ABSTRACT FROM AUTHOR]

The article discusses comments on a paper by S. Allaf and colleagues about the comparison of legal cannabis markets from various countries. Topics mentioned include the impact of the increase in acute cannabis poisoning in pediatric patients on the decision to legalize and decriminalize cannabis products, the ban of cannabis products with high content of tetrahydrocannabinol, and the advantages of regulations to minimize harm caused by cannabis products.

The relationship between cannabis and psychosis and schizophrenia has tested the field of addiction for decades, and in some ways serves as measure of our ability to provide a credible contribution to public health. As cannabis is used widely, many people are interested in the risks the drug poses to mental health. This paper focuses upon a seminal study examining this, the trajectory of subsequent research findings and what this has meant for understanding and communicating risk factor information. These studies provided evidence of a dose-response relationship between cannabis and psychosis, and that for those individuals with schizophrenia cannabis exacerbated their symptoms. The findings fit with a multi-causal model in which vulnerability interacts with a precipitating agent to produce a disease outcome. Even though this is a common model in epidemiology, it has proved difficult to communicate it in this case. This may be because at a population level the increased risk is weak and the vulnerabilities relatively rare. It may also be because people bring strongly held preconceptions to interpreting a complex multi-causal phenomenon. [ABSTRACT FROM AUTHOR]

Background and aims Prohibitions on producing, distributing and selling cannabis are loosening in various jurisdictions around the world. This paper describes the diversification of cannabis supply laws and discusses the challenges to and opportunities for learning from these changes. Methods We document changes in cannabis supply laws that de jure legalized cannabis production for medical and/or non-medical purposes (excluding industrial hemp) in Australasia, Europe, North America and South America. We also highlight challenges to evaluating these legal changes based on our experiences studying cannabis laws and policies in the United States. Findings As of August 2016, two countries have passed laws to legalize large-scale cannabis production for non-medical purposes at the national (Uruguay) or subnational level (four US states). At least nine other countries legally allow (or will soon allow) cannabis to be supplied for medicinal purposes. Most of the changes in cannabis supply laws have occurred since 2010. The data available in most countries are inadequate for rigorously evaluating the changes in cannabis supply laws. Conclusion The evidence base for assessing changes in cannabis supply laws remains weak. Efforts should focus upon collecting information about quantities consumed and market transactions as well as validating self-report surveys. [ABSTRACT FROM AUTHOR]

Background and Aims In 2014 the legislature of Vermont, USA passed a law requiring the Secretary of Administration to report on the consequences of legalizing marijuana. The RAND Corporation was commissioned to write that report. This paper summarizes insights from that analysis that are germane to other jurisdictions. Method Translation of key findings from the RAND Corporation report to the broader policy debate. Results Marijuana legalization encompasses a wide range of possible regimes, distinguished along at least four dimensions: which organizations are allowed to produce and supply the drug, the regulations under which they operate, the nature of the products that can be distributed and taxes and prices. Vermont's decriminalization had already cut its costs of enforcing marijuana prohibition against adults to about $1 per resident per year. That is probably less than the cost of regulating a legal market. Revenues from taxing residents' purchases after legalization could be many times that amount, so the main fiscal cost of prohibition after decriminalization relative to outright legalization may be foregone tax revenues, not enforcement costs. Approximately 40 times as many users live within 200 miles of Vermont's borders as live within the state; drug tourism and associated tax revenues will be important considerations, as will be the response of other states. Indeed, if another state legalized with lower taxes, that could undermine the ability to collect taxes on even Vermont residents' purchases. Conclusions Analysis of possible outcomes if Vermont, USA, legalized marijuana reveal that choices about how, and not just whether, to legalize a drug can have profound consequences for the effects on health and social wellbeing, and the choices of one jurisdiction can affect the options and incentives available to other jurisdictions. [ABSTRACT FROM AUTHOR]

A correction to the article by O. Rogeburg et al. which appeared in the August 2016 issue is presented.

Aims Drug policy strategies and discussions often use prevalence of drug use as a primary performance indicator. However, three other indicators are at least as relevant: the number of heavy users, total expenditures and total amount consumed. This paper stems from our efforts to develop annual estimates of these three measures for cocaine (including crack), heroin, marijuana and methamphetamine in the United States. Methods The estimates exploit complementary strengths of a general population survey ( National Survey on Drug Use and Health) and both survey and urinalysis test result data for arrestees ( Arrestee Drug Abuse Monitoring Program), supplemented by many other data sources. Results Throughout the 2000s US drug users spent in the order of $100 billion annually on these drugs, although the spending distribution and use patterns changed dramatically. From 2006 to 2010, the amount of marijuana consumed in the United States probably increased by more than 30%, while the amount of cocaine consumed in the United States fell by approximately 50%. These figures are consistent with supply-side indicators, such as seizures and production estimates. For all the drugs, total consumption and expenditures are driven by the minority of users who consume on 21 or more days each month. Conclusions Even for established drugs, consumption can change rapidly. The halving of the cocaine market in five years and the parallel (but independent) large rise in daily/near-daily marijuana use are major events that were not anticipated by the expert community and raise important theoretical, research, and policy issues. [ABSTRACT FROM AUTHOR]

Background and Aims: The prevalence of cannabis use based on self‐reports is likely to be underestimated in population surveys, especially in contexts where its use is a criminal offence. Indirect survey methods ask sensitive questions ensuring that answers cannot be identified with an individual respondent, therefore potentially resulting in more reliable estimates. We aimed to measure whether the indirect survey method 'randomized response technique' (RRT) increased response rate and/or increased disclosure of cannabis use among young adults compared with a traditional survey. Design: We conducted two parallel nation‐wide surveys during the spring and the summer of 2021. The first survey was a traditional questionnaire‐based one (focusing on substance use and gambling). The second survey applied an indirect survey method known as 'the cross‐wise model' to questions related to cannabis use. The two surveys employed identical procedures (e.g. invitations, reminders and wording of the questions) Setting and Participants: The participants were young adults (aged 18–29 years) living in Sweden. The traditional survey had 1200 respondents (56.9% women) and the indirect survey had 2951 respondents (53.6% women). Measurements In both surveys, cannabis use was assessed according to three time‐frames: life‐time use; use during the past year; and use during the past 30 days. Findings The estimated prevalence of cannabis use was two‐ to threefold higher on all measures when estimated using the indirect survey method compared with the traditional survey: use during life‐time (43.2 versus 27.3%); during the past year (19.2 versus 10.4%); and during the past 30 days (13.2 versus 3.7%). The discrepancy was larger among males and individuals with an education shorter than 10 years, who were unemployed, and who were born in non‐European countries. Conclusions: Indirect survey methods may provide more accurate estimates than traditional surveys on prevalence of self‐reported cannabis use. [ABSTRACT FROM AUTHOR]

An increased use of high‐potency cannabis products since cannabis legalization in the United States, Canada and elsewhere may increase cannabis‐related harm. Policymakers have good reasons for regulating more potent cannabis in ways that minimize harm, using approaches similar to those used to regulate alcohol; namely, banning the sale of high‐potency cannabis, setting a cap on tetrahydrocannabinol (THC) content and imposing higher rates of taxes on more potent cannabis products. Given the difficulty that US policymakers have had in regulating cannabis extracts and edibles, governments that are planning to legalize cannabis need to put policies on extracts into enabling legislation and evaluate the impact of these policies on cannabis use and cannabis‐related harms. [ABSTRACT FROM AUTHOR]

Background and aims: The Marijuana Purchase Task (MPT) is increasingly used to measure cannabis reinforcing value and has potential use for cannabis etiological and regulatory research. This meta‐analysis sought to evaluate for the first time the MPT's concurrent validity in relation to cannabis involvement. Methods: Electronic databases and pre‐print repositories were searched for MPT studies that examined the cross‐sectional relationship between frequency and quantity of cannabis use, problems, dependence, and five MPT indicators: intensity (i.e. unrestricted consumption), Omax (i.e. maximum consumption), Pmax (i.e. price at which demand becomes elastic), breakpoint (i.e. first price at which consumption ceases), and elasticity (i.e. sensitivity to rising costs). Random effects meta‐analyses of cross‐sectional effect sizes were conducted, with Q tests for examining differences by cannabis variables, meta‐regression to test quantitative moderators, and publication bias assessment. Moderators included sex, number of MPT prices, variable transformations, and year of publication. Populations included community and clinical samples. Results: The searches yielded 14 studies (n = 4077, median % females: 44.8%: weighted average age = 29.08 [SD = 6.82]), published between 2015 and 2022. Intensity, Omax, and elasticity showed the most robust concurrent validity (|r's| = 0.147–325, ps < 0.014) with the largest significant effect sizes for quantity (|r| intensity = 0.325) and cannabis dependence (|r| Omax = 0.320, |r| intensity = 0.305, |r| elasticity = 0.303). Higher proportion of males was associated with increased estimates for elasticity‐quantity and Pmax‐problems. Higher number of MPT prices significantly altered magnitude of effects sizes for Pmax and problems, suggesting biased estimations if excessively low prices are considered. Methodological quality was generally good, and minimal evidence of publication bias was observed. Conclusions: The marijuana purchase task presents adequate concurrent validity to measure cannabis demand, most robustly for intensity, Omax, and elasticity. Moderating effects by sex suggest potentially meaningful sex differences in the reinforcing value of cannabis. [ABSTRACT FROM AUTHOR]

Background and aims: Mixed results have been reported on the association between prenatal cannabis exposure and preterm birth. This study aimed to examine the magnitude and consistency of associations reported between prenatal cannabis exposure and preterm birth. Methods: This review was guided by the Preferred Reporting Items for Systematic Review and Meta‐Analysis (PRISMA) guidelines. We performed a comprehensive search of the literature on the following electronic databases: PubMed, EMBASE, SCOPUS, Psych‐INFO and Web of Science. The revised version of the Newcastle–Ottawa Scale (NOS) was used to appraise the methodological quality of the studies included in this review. Inverse variance weighted random‐effects cumulative meta‐analysis was undertaken to pool adjusted odds ratios (aOR) after sequential inclusion of each newly published study over time. The OR and 95% confidence interval (CI) limits required (stability threshold) for a new study to move the cumulative odds ratio to the null were also computed. Results: A total of 27 observational studies published between 1986 and 2022 were included in the final cumulative meta‐analysis. The sample size of the studies ranged from 304 to 4.83 million births. Prenatal cannabis exposure was associated with an increased risk of preterm birth (pooled aOR = 1.35, 95% CI = 1.24–1.48). The stability threshold was 0.74 (95% CI limit = 0.81) by the end of 2022. Conclusions: Offspring exposed to maternal prenatal cannabis use was associated with higher risk of preterm birth, which warrants public health messages to avoid such exposure, particularly during pregnancy. [ABSTRACT FROM AUTHOR]

Aims: To measure longitudinal trajectories of marijuana use in four tobacco/nicotine products (hand‐rolled cigarettes/spliffs, cigars/blunts, hookah, and e‐cigarettes) among young adult Texas college students from 2015 to 2019. Design: This study used six consecutive waves of data from the marketing and promotions across colleges in Texas project (Project M‐PACT), a longitudinal study of the tobacco behaviors of young adult college students. The first four waves were collected every 6 months (fall 2015‐spring 2017), and the final two waves were conducted yearly (spring 2018 and 2019). Growth curve models measured trajectories of marijuana use in tobacco products across the 3.5‐year period. Setting and Participants: A total of 4857 young adults from 24 colleges in the largest metropolitan areas of Texas, United States (Austin, Dallas, Houston, and San Antonio): mean age = 21.0, SD = 2.3; 64.2% assigned female; 36.1% non‐Hispanic white, 31.0% Hispanic, and 33.0% other or combination race/ethnicity. Measurements Participants completed online surveys assessing their past 6‐month use of marijuana in four tobacco products of interest (spliffs, blunts, hookah, and e‐cigarettes) and socio‐demographic variables (sex, race/ethnicity, age, 2‐year/4‐year college attendance, and sexual and gender minority identity). Findings Observed vaping marijuana in e‐cigarettes approximately doubled between the spring of 2015 and the spring of 2019, from 11.8% to 23.9% following a quadratic time trend (linear OR = 0.84, 95% CI = 0.73–0.97, quadratic OR = 1.18, CI = 1.13–1.22). This same time period saw a quadratic decline in using marijuana in hookah (P < 0.001) and no changes in using hand‐rolled cigarettes/spliffs or cigars/blunts for marijuana delivery. Conclusions: The popularity of nicotine e‐cigarettes appears to be expanding the avenues for marijuana delivery among young adults in Texas, United States. [ABSTRACT FROM AUTHOR]

Aims: There is a growing body of literature exploring the types of substance‐related content and their portrayals on various social media platforms. We aimed to summarize how content related to substances is portrayed on various social media platforms. Methods: This systematic review was pre‐registered on PROSPERO (ref: CRD42021291853). A comprehensive search was conducted in the databases of PubMed, Scopus, PsycINFO and Web of Science in April 2021. Original qualitative studies published post‐2004 that included thematic and sentiment analyses of social media content on tobacco, alcohol, psychostimulant, e‐cigarette, cannabis, opiate, stimulant/amphetamine, inhalant and novel psychoactive substance were included. Social media platforms were defined as online web‐ or application‐based platforms that allowed users to generate content and interact via 'liking', comment or messaging features. Only studies that included summative and/or thematic content analyses of substance‐related social media content were included. Results: A total of 73 studies, which covered 15 905 182 substance‐related posts on Twitter, YouTube, Instagram, Pinterest, TikTok and Weibo, were identified. A total of 76.3% of all substance‐related content was positive in its depiction of substance use, with 20.2% of content depicting use negatively. Sentiment regarding opiate use however was commonly negative (55.5%). Most studies identified themes relating to Health, Safety and Harms (65.0%) of substance use. Themes relating to Promotions/Advertisements (63.3%), Informative content (55.0%) and Use behaviours (43.3%) were also frequently identified. Conclusions: Substance‐related content that promotes engagement with substance use or actively depicts use appears to be widely available on social media. The large public presence of this content may have concerning influences on attitudes, behaviours and risk perceptions relating to substance use, particularly among the most vulnerable and heaviest users of social media—adolescents and young adults. [ABSTRACT FROM AUTHOR]

The author comments on the use of double evidential standards in assessing the adverse and beneficial effects of cannabis. Topics discussed include argument of some critics of publicly funded research on cannabis use, a popular argument for legalization, and characteristics of people with cannabis use disorders (CUDs.)

Aims: To estimate the prevalence of family members affected by addictive disorders (FMA) with regard to various types of addictive disorders, and self‐rated health and depression in the general population. Design: Cross‐sectional general population survey. Setting: The German Health Update study (GEDA) 2014/2015, a nationally representative panel of German residents aged 15 years or older. Participants: A total of 24 824 residents aged 15 years or older. Measurements Participants were asked if they had a family member with current or past addictive disorder, the type of addiction and the relationship status. In addition, self‐rated health and depression were assessed using standardized questionnaires. Findings Of the respondents, 9.5% [95% confidence interval (CI) = 9.0–10.0] reported being affected by a current addictive disorder of a relative (cFMA), with a further 4.5% (95% CI = 4.2–4.9) reported having been affected by the addictive disorders of a relative in the past but not within the last 12 months (pFMA). Most FMAs reported having been affected by disorders due to alcohol, followed by cannabis and other drugs. Compared with life‐time non‐FMAs, FMAs reported significantly (P < 0.001) higher odds ratios for depression (cFM = 2.437; 95% CI = 2.082–2.853; pFMA = 1.850; 95% CI = 1.519–2.253) and ill‐health (cFMA = 1.574; 95% CI = 1.374–1.805; pFMA = 1.297; 95% CI = 1.082–1.555). Conclusions: In Germany, family members affected by addictive disorder are a substantial group within the general population. This group is characterized by ill‐health and has not yet been adequately addressed by the addiction treatment system. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the commentary "Risk for Involvement in Road Traffic Crash During Acute Cannabis Intoxication" by H. Gjerde and J. Morland in volume 111 of the periodical.

The authors comment on an article by W. Hall and colleagues on regulating delta-9-tetrahydrocannabinol (THC) content in cannabis products. Topics include policy options discussed by W. Hall and colleagues with a view to reduce cannabis-related harm, the introduction by Quebec and Uruguay of caps on THC levels for the products supplied through the legal market, and possible impact of accommodating different THC concentrations among different legal supply options.

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. [ABSTRACT FROM AUTHOR]

Background and aims: Cannabis and alcohol are frequently detected in fatal and injury motor vehicle crashes. While epidemiological meta‐analyses of cannabis and alcohol have found associations with an increase in crash risk, convergent evidence from driving performance measures is insufficiently quantitatively characterized. Our objectives were to quantify the magnitude of the effect of cannabis and alcohol—alone and in combination—on driving performance and behaviour. Methods: Systematic review and meta‐analysis. We systematically searched Academic Search Complete, CINAHL, Embase, Scopus, Google Scholar, MEDLINE, PsycINFO, SPORTDiscus and TRID. Of the 616 studies that underwent full‐text review, this meta‐analysis represents 57 studies and 1725 participants. We extracted data for hazard response time, lateral position variability, lane deviations or excursions, time out of lane, driving speed, driving speed variability, speed violations, time speeding, headway, headway variability and crashes from experimental driving studies (i.e. driving simulator, closed‐course, on‐road) involving cannabis and/or alcohol administration. We reported meta‐analyses of effect sizes using Hedges' g and r. Results: Cannabis alone was associated with impaired lateral control [e.g. g = 0.331, 95% confidence interval (CI) = 0.212–0.451 for lateral position variability; g = 0.198, 95% CI = 0.001–0.395 for lane excursions) and decreased driving speed (g = –0.176, 95% CI = –0.298 to –0.053]. The combination of cannabis and alcohol was associated with greater driving performance decrements than either drug in isolation [e.g. g = 0.480, 95% CI = 0.096–0.865 for lateral position variability (combination versus alcohol); g = 0.525, 95% CI = 0.049–1.002 for time out of lane (versus alcohol); g = 0.336, 95% CI = 0.036–0.636 for lateral position variability (combination versus cannabis; g = 0.475, 95% CI = 0.002–0.949 for time out of lane (combination versus cannabis)]. Subgroup analyses indicated that the effects of cannabis on driving performance measures were similar to low blood alcohol concentrations. A scarcity of data and study heterogeneity limited the interpretation of some measures. Conclusions: This meta‐analysis indicates that cannabis, like alcohol, impairs driving, and the combination of the two drugs is more detrimental to driving performance than either in isolation. [ABSTRACT FROM AUTHOR]

Background: The lack of an agreed international minimum approach to measuring cannabis use hinders the integration of multidisciplinary evidence on the psychosocial, neurocognitive, clinical and public health consequences of cannabis use. Methods: A group of 25 international expert cannabis researchers convened to discuss a multidisciplinary framework for minimum standards to measure cannabis use globally in diverse settings. Results: The expert‐based consensus agreed upon a three‐layered hierarchical framework. Each layer—universal measures, detailed self‐report and biological measures—reflected different research priorities and minimum standards, costs and ease of implementation. Additional work is needed to develop valid and precise assessments. Conclusions: Consistent use of the proposed framework across research, public health, clinical practice and medical settings would facilitate harmonisation of international evidence on cannabis consumption, related harms and approaches to their mitigation. [ABSTRACT FROM AUTHOR]

Background/aims: Research linking orbitofrontal cortex (OFC) structure and substance use disorders (SUDs) is largely correlational and often implies a causal effect of addiction/substance exposure on the brain, but familial risk factors (e.g. genetic liability) may confound these associations. We tested whether associations between alcohol, cannabis and tobacco use disorders and OFC thickness reflected the potential causal effects of familial risk or SUDs‐related consequences (e.g. substance exposure). Design A co‐twin control/discordant twin design separated familial risk confounding from SUD‐related consequences. Setting/participants: A population‐based sample of 436 24‐year‐old twins (62% monozygotic) from the Minnesota Twin Family Study, USA. Measurements Alcohol, cannabis and tobacco use disorders were assessed using the Composite International Diagnostic Interview—Substance Abuse Module. Cortical thickness of the medial and lateral OFC (mOFC and lOFC, respectively) was assessed using magnetic resonance imaging (MRI). Findings Lower mOFC (P‐values ≤ 0.006) but not lOFC (P‐values ≥ 0.190) thickness was observed in diagnosed individuals (n = 185) relative to non‐SUD controls (n = 251). Co‐twin control analyses offered evidence that mOFC associations were consistent with familial risk across SUDs (between‐pair effect: P‐values ≤ 0.047) and the independent consequences of having an alcohol or cannabis use disorder (within‐pair effect: P‐values ≤ 0.024). That is, within alcohol/cannabis discordant twin pairs, affected twins had significantly lower mOFC thickness compared with their unaffected co‐twins. Conclusions: A confounder‐adjusted analysis of the Minnesota Twin Family Study appeared to indicate that, beyond a substance use disorders general familial risk effect, the experience of an alcohol or cannabis use disorder in emerging adulthood reduces the thickness of the medial orbitofrontal cortex, a region associated with value‐guided decision‐making. [ABSTRACT FROM AUTHOR]

Background and Aims: There has been an increase in the potency of cannabis during the last two decades and adoption of a novel method of administration—vaping. YouTube, a social media platform, has become a popular source to access cannabis‐related information. This study aimed to identify cannabis vaping YouTube videos from 2016 to 2020 and examine the themes and metrics. Design Cross‐sectional sample of 200 YouTube videos. Setting: YouTube, an on‐line video sharing platform. Measurements Videos related to cannabis vaping were identified using the search terms: 'vaping cannabis', 'vaping weed', 'vaping marijuana' and 'vaping THC' [tetrahydrocannabinol]. Videos were independently coded by two researchers. The number of views, likes, dislikes and comments were also collected. Robust regression was used to analyse the relationship between identified video themes and video metrics. Findings Six themes were identified: 'advertisement', 'product review', 'celebratory', 'reflective', 'how‐to' and 'warning'. The 'how‐to' and 'celebratory' videos received the highest number of views and likes. The most popular video was viewed more than 4 000 000 times. Many videos portrayed risky behaviour (e.g. vaping a whole THC cartridge in a single setting). Fifty‐two percent of these videos had no age access restrictions. The robust regression model also found that engagement metric was positively associated with 'reflective' videos and negatively associated with 'advertisement' videos. Conclusions: A large number of videos on cannabis vaping are available on‐line without age‐restriction. Videos that portrayed risky behaviour appear to be prevalent. [ABSTRACT FROM AUTHOR]

Background and aims: In Great Britain, cannabis and tobacco are commonly used substances, both independently and together. Use of either substance is associated with mental health problems, but prevalence of co‐use within these populations is unknown. We aimed to (1) estimate prevalence of cannabis use, frequency of use and routes of administration (ROA) among tobacco smokers and non‐smokers and (2) investigate mental health problems among non‐users, tobacco‐only, cannabis‐only and co‐users of both substances. Design Cross‐sectional national on‐line survey (Action on Smoking and Health) fielded in February–March 2020. Setting: Great Britain. Participants: Adults in Great Britain aged ≥ 18 years (n = 12 809) Measurements Tobacco use status [smoker (daily or non‐daily) or non‐smoker (never or ex‐smoker)], cannabis use frequency (never to daily), detailed ROAs of cannabis, self‐reported treatment for mental health disorders (depression, anxiety and any). Statistically weighted prevalence estimates were computed to ensure representativeness. Correlates were assessed using χ2 tests and logistic regression. Findings In Great Britain in 2020, 7.1% of the sample had used cannabis in the past year. Tobacco smokers had greater odds of using cannabis in the past year (21.9%) and using cannabis daily (8.7%) than non‐smokers [past‐year: 4.7%; adjusted odds ratio (aOR) = 10.07, 95% confidence interval (CI) = 8.4–12.0; daily: 0.7%; aOR = 24.6, 95% CI = 18.0–33.6)]. Co‐administration with tobacco was common (46.2% of non‐smokers, 80.8% of tobacco smokers). Co‐users reported the highest prevalence of any treatment for mental health problems (54.2%) in comparison to cannabis‐only (45.8%), tobacco‐only (33.2%) and non‐users (22.7%; all P ≤ 0.05). Conclusion: Approximately one in 13 adults in Great Britain reports having used cannabis in the past year, approximately four times as many among cigarette smokers as non‐smokers. Co‐administration of cannabis and tobacco, via smoking, appears to be common, including among self‐identified non‐smokers. Mental health problems appear to be particularly common among dual users. [ABSTRACT FROM AUTHOR]

Background and aims: Opening up access to scheduled drugs such as cannabis in the United Kingdom rarely happens, yet on 1 November 2018 the United Kingdom changed the law to allow cannabis‐derived products to be prescribed for medicinal purposes, albeit in tightly controlled circumstances. This followed substantial media interest in the cases of two children with epilepsy. This article focuses upon the role of scandal in bringing about legislative change. Methods: We used political science and social policy theories (punctuated equilibrium theory and scandal theory) to guide a qualitative content analysis of media articles published in 2018 in UK national newspapers. We focused in particular on the 6‐month period prior to the policy change. Results: The concentrated attention by the media given to the suffering of children with epilepsy appears to have prompted the rapid change in policy by the UK government. A variety of strategies were used to develop a highly emotive response to garner support for reform. Media stories emphasized the injustice of two extremely sick children being unable to access the medicine they apparently needed to enable them to have a 'normal' childhood. Three groups of 'claim‐makers' were identified as important in influencing public opinion: families, high‐profile individuals and campaigning groups. Conclusions: The case of medicinal cannabis in the United Kingdom suggests that policy reform can occur when a scandal is successfully manufactured. We must be cautious, however, about over‐emphasizing the role of scandal as a driver of policy change in this context: only a limited set of circumstances will permit a prescription for cannabis‐based medicine to be issued in the United Kingdom. [ABSTRACT FROM AUTHOR]

Background and aims: Existing evidence for a link between alcohol use and memory impairments in adolescents and young adults is largely correlational. We aimed to determine whether associations between drinking and episodic memory were consistent with a causal effect of drinking or accounted for by familial factors confounding such associations. Because cannabis use is associated with a similar pattern of performance on episodic memory measures, we assessed whether any associations might be attributable to concurrent cannabis use. Design, setting and participants: Observational study of individuals aged approximately 20–29 years, comprising two independent population‐based cohorts of twins. A co‐twin–control design permitted an estimate of alcohol exposure effects free of shared genetic and environmental confounding influences. Significant associations were followed‐up with twin‐difference analyses. Propensity scores derived from measures collected at age 11 were used to adjust for unshared confounders. Participants in both cohorts were assessed from the age of 11 (n = 1251) under the auspices of the Minnesota Center for Twin and Family Research. Measurements Regression analyses with cumulative alcohol use as the predictor of interest. Multiple measures of attention, learning and memory from a widely used episodic memory task constituted dependent variables. Findings Drinking was associated with poorer attention (P ≤ 0.003) and learning (P ≤ 0.008). Results were similar across the two cohorts. The within‐pair effect in twin‐difference analyses was significant only for measures of learning (P‐values ≤ 0.004). Results were not due to measured unshared confounders or cannabis use. Drinking in adolescence (to age 20) and early adulthood (between 20 and 29) exerted independent effects on learning. Conclusions: There appears to be a robust and specific association between drinking and learning that can be reproduced across cohorts, is not easily accounted for by confounding factors or concurrent cannabis use and is consistent with a causal influence of drinking. [ABSTRACT FROM AUTHOR]

Background and Aims: Changes in cannabis legalization and availability in Australia necessitate monitoring use and attitudes. We estimated age–period–cohort effects of past‐year cannabis use and attitudes toward criminalization and legalization. Design Analysis of six waves of the Australian National Drug Strategy Household Survey (NDSHS) every 3 years (2001–2016). Setting and participants: The study was nationally representative of Australian households using multistage random sampling, totaling 145 168 respondents 18–79 years old. Data were collected using telephone, face‐to‐face, and drop‐and‐collect. Sample sizes per analysis varied based on data availability (~107 000–127 000 per model). Measurements Six waves of data for past‐year cannabis use (by sex and education), attitudes toward criminalization and legalization. Findings Past‐year cannabis use decreased in young adults ages 18–35 from 2001–2016 (25.1%–18.6%) and increased in middle adults ages 36–55 (8.6%–10.1%) and older adults ages 56–79 (0.6%–3.0%). We observed a positive period effect and negative cohort effect for recent cohorts for past‐year use (e.g. 1955 cohort had 1.41 (95% CI: [1.11, 1.70]) increased log odds vs. 1998 cohort had −2.86 (95% CI: [−3.17, −2.55]) increased log odds) compared with the mean across years. Results were consistent by sex and varied by education. We observed a negative period effect for criminalization favorability (0.14 (95% CI: [0.003, 0.28]) increased log odds in 2001 vs. ‐0.31 (95% CI: [−0.45, −0.17]) increased log odds in 2016) and positive cohort effect for recent cohorts. Last, we observed a positive period effect for legalization support (−0.03 (95% CI: [−0.20, 0.14]) increased log odds in 2001 vs. 0.38 (95% CI: [0.22, 0.55]) increased log odds in 2016) and negative cohort effect for recent cohorts. Conclusion: Cannabis use appears to be increasing in Australia among adults over 35, while decreasing among adolescents and young adults. Legalization support also appears to have been increasing since 2007, signaling discordance between use and attitudes among adolescents and young adults, and potentially predicting increases in use over time. [ABSTRACT FROM AUTHOR]

Background and aims: Cannabis products with high delta‐9‐tetrahydrocannabinol (THC) concentrations carry an increased risk of addiction and mental health disorders, while it has been suggested that cannabidiol (CBD) may moderate the effects of THC. This study aimed to systematically review and meta‐analyse changes in THC and CBD concentrations in cannabis over time (PROSPERO registration: CRD42019130055). Design Embase, MEDLINE® and Epub Ahead of Print, In‐Process and Other Non‐Indexed Citations and Daily, Global Health, PsycINFO and Scopus were searched from inception to 27/03/2019 for observational studies reporting changes in mean THC and/or CBD concentration in cannabis over at least three annual time points. Searches and extraction were conducted by two independent reviewers. Random effects meta‐regression models estimated annual changes in THC and CBD for each product within each study; these estimates were pooled across studies in random effects models. Results: We identified 12 eligible studies from the USA, UK, Netherlands, France, Denmark, Italy and New Zealand. For all herbal cannabis, THC concentrations increased by 0.29% each year (95% CI: 0.11, 0.47), P < 0.001 based on 66 747 cannabis samples from eight studies, 1970–2017. For cannabis resin, THC concentrations increased by 0.57% each year (95% CI: 0.10, 1.03), P = 0.017 based on 17 371 samples from eight studies, 1975–2017. There was no evidence for changes in CBD in herbal cannabis [−0.01% (95% CI: −0.02, 0.01), P = 0.280; 49 434 samples from five studies, 1995–2017] or cannabis resin [0.03% (95% CI: −0.11, 0.18), P = 0.651; 11 382 samples from six studies, 1992–2017]. Risk of bias was low apart from non‐random sampling in most studies. There was evidence of moderate to substantial heterogeneity. Conclusions: Concentrations of delta‐9‐tetrahydrocannabinol (THC) in international cannabis markets increased from 1970 to 2017 while cannabidiol (CBD) remained stable. Increases in THC were greater in cannabis resin than herbal cannabis. Rising THC in herbal cannabis was attributable to an increased market share of high‐THC sinsemilla relative to low‐THC traditional herbal cannabis. [ABSTRACT FROM AUTHOR]

Aims: To assess the effectiveness of Take it personal!, a prevention programme for individuals with mild intellectual disabilities and borderline intellectual functioning (MID‐BIF) and substance use (SU). The prevention programme aims to reduce SU (alcohol, cannabis and illicit drugs) among experimental to problematic substance users. Design A quasi‐experimental design with two arms and a 3‐month follow‐up. Setting: Adolescents were recruited from 14 treatment centres in the Netherlands specialized in offering intra‐ and extramural care for people with MID‐BIF and behavioural problems. Participants: Data were collected from 66 individuals with MID‐BIF assigned either to the intervention condition (n = 34) or to the control condition (n = 32). Interventions: Take it personal! was designed to target four personality traits: sensation‐seeking, impulsive behaviour, anxiety sensitivity and negative thinking. For each of these profiles, interventions were developed that were structurally the same but contained different personality‐specific materials, games and exercises. The control group received care as usual. Measurements Primary outcomes at 3‐month follow‐up were frequency of SU, severity of SU and binge drinking. Results: Results showed intervention effects for SU frequency (F(1, 50.43) = 9.27, P = 0.004) and binge drinking (F(1, 48.02) = 8.63, P = 0.005), but not for severity of SU (F(1, 42.09) = 2.20, P = 0.145). Conclusions: A prevention programme to reduce substance use among experimental to problematic users with mild intellectual disabilities and borderline intellectual functioning helped participants to decrease substance use frequency and binge drinking. [ABSTRACT FROM AUTHOR]

Aims: To identify prototypical developmental patterns of tobacco product and cannabis use and co‐use initiation during adolescence, and determine risk factors for and consequences of these initiation patterns. Design Prospective repeated‐measures cohort with eight semi‐annual assessments during high school. Multiple‐event process survival mixture modeling identified latent initiation classes with distinct patterns of variation in timing of use initiation of tobacco products and cannabis. We then estimated: (1) associations of baseline risk factors with membership in initiation classes and (2) differences between initiation classes in frequency of cannabis and tobacco product use at the final assessment. Setting: Ten high schools in the Los Angeles, CA, USA metropolitan area, 2013–17. Participants: Students [1031 (45.4%) males; mean (standard deviation) age at baseline = 14.6 (0.39) years] who had never used any tobacco products or cannabis at baseline 9th grade assessment (n = 2272). Measurements: Self‐report measures of electronic cigarette (e‐cigarette), combustible cigarette, hookah, cigar/cigarillos and cannabis use were collected at each assessment. Findings Four distinct tobacco and cannabis use initiation classes were identified: (1) early and high‐risk cannabis and polytobacco initiators (n = 116; 5.1%); (2) early cannabis and polytobacco initiators (n = 172; 7.6%); (3) late cannabis and e‐cigarette initiators (n = 431; 19.0%); and (4) abstainers (n = 1553; 68.4%). At baseline, older age for the early and high‐risk cannabis and polytobacco initiators [odds ratio (OR) = 1.22, 95% confidence interval (CI) = 1.10, 1.35, P < 0.001], peer cannabis use (OR = 1.60, 95% CI = 1.23, 2.08, P < 0.001) and delinquent behavior (OR = 1.30, 95% CI = 1.08, 1.55, P = 0.004) were associated with membership in the three initiation classes (versus abstainers). Membership in the early and high‐risk cannabis and polytobacco initiators class (versus three other classes) was significantly associated with increased past 30‐day frequency and daily intensity of use at the final assessment (P‐values < 0.001). Conclusions: Older age, peer cannabis use and delinquent behavior appear to be risk factors for the initiation of tobacco/cannabis product use among high school students in the Los Angeles metropolitan region. Early and higher‐risk polyproduct use initiation appears to be associated with greater escalation of past 30‐day and daily tobacco and cannabis use at the end of the high school. [ABSTRACT FROM AUTHOR]

Background and aims: The construct of susceptibility to substance use initiation (i.e. cognitive proclivity to future use) is critical for prevention efforts in adolescent populations. This study aimed to provide empirical evidence for the validity of the susceptibility construct for different cannabis products (i.e. combustible, edible or vaporized cannabis), and evaluate whether susceptibility measures are predictive of subsequent initiation. Design Prospective cohort study including baseline data (Spring 2015) and four follow‐up surveys administered every 6 months through Spring 2017. Setting: Ten schools in the Los Angeles, California metropolitan area. Participants: Adolescents [n = 2100; mean age = 16.1; standard deviation (SD) = 0.41; 54% female] who reported never having used any cannabis product at baseline. Measurements We assessed five indices of a susceptibility to use cannabis composite index at baseline, adapted from a validated tobacco use index (intention to use, willingness, curiosity and positive/negative cannabis use outcome expectancies, with four response categories, definitely not [1] to definitely yes [4]), by cannabis product (combustible, edible or vaporized). A composite index was created for each product by averaging responses across the five susceptibility items. Subsequent initiation of use of each cannabis product was assessed at each follow‐up wave. Findings Factorial validity for unidimensionality for each five‐item index (by product) was confirmed. The composite index for susceptibility to cannabis use was greatest for combustible (mean = 1.44; SD = 0.58), moderate for edible (mean = 1.37; SD = 0.53) and lowest for vaporized cannabis (mean = 1.30; SD = 0.44). The associations of each composite susceptibility index with subsequent initiation of that product and each of the other cannabis products over follow‐up (i.e. cross‐product associations) were statistically significant, with hazard ratios ranging from 2.30 to 2.80 across 24 months of follow‐up (all Ps < 0.05). Conclusions: A five‐item susceptibility to cannabis use composite index (by product) appears to be useful for characterizing and predicting youth at risk for cannabis use initiation across a spectrum of cannabis products. [ABSTRACT FROM AUTHOR]

Background and aims: While cannabis use has been found to impair motor vehicle driving, the association between cannabis legalization and motor vehicle fatalities is unclear. In Uruguay in December 2013, cannabis for recreational purposes was legalized. This study assessed the association between implementation of this law and changes in traffic fatality rates. Design Interrupted time–series analysis of traffic fatality rates of light motor vehicle drivers and motorcyclists in urban and rural settings. Changes are reported as step and trend effects against modeled trends in the absence of legalization. Setting: Uruguay, Montevideo and four rural provinces (Colonia, Florida, Río Negro and San José) from 1 January 2012 to 31 December 2017. Cases and measurement Weekly traffic fatalities of light motor vehicle drivers and motorcyclists per type of vehicle. Data were gathered from the National Road Safety Agency of Uruguay and the Ministry of Transport and Public Works, respectively. Results: Cannabis legalization was associated with a 52.4% immediate increase [95% confidence interval (CI) = 11.6, 93.3, P = 0.012] in the light motor vehicle driver's fatality rate. However, no significant change in the motorcyclists' fatality rate was observed. In Montevideo the legislation was associated with an absolute increase in its light motor vehicle driver's fatality rate by 0.06 (95% CI = 0.01, 0.11, P = 0.025), but no significant associations were observed in rural settings. Conclusions: In Uruguay, the 2013 legislation legalizing recreational cannabis consumption may have been associated with an increase in fatal motor vehicle crashes, particularly in light motor‐vehicle drivers and urban settings. [ABSTRACT FROM AUTHOR]

Background and Aims: Eleven US states and the District of Columbia have legalized the non‐medical use of marijuana. Public marijuana smoking is generally prohibited, although some states have considered exemptions. This study assessed attitudes about public marijuana smoking, perceptions of harm from marijuana second‐hand smoke (SHS) and self‐reported marijuana SHS exposure. Design Internet panel survey fielded in June–July 2018. Setting: United States. Participants: US adults aged ≥ 18 years (n = 4088). Measurements Current (past‐30 day) tobacco product use, current marijuana use, opinions about public indoor marijuana smoking, perceptions of harm from marijuana SHS and self‐reported past‐7 day exposure to marijuana SHS in public indoor or outdoor areas were assessed. Weighted prevalence estimates were computed and correlates were assessed using logistic and multinomial regression. Findings Overall, 27.4% [95% confidence interval (CI) = 25.7, 29.1] of adults reported past‐week marijuana SHS exposure in indoor and/or outdoor public areas; younger adults, blacks, Hispanics, those in the Northeast or West, and current marijuana and/or tobacco users were more commonly exposed (Ps < 0.0001). More than half of adults (52.4%; 95% CI = 50.7, 54.2) regarded marijuana SHS as harmful, and most (81.0%; 95% CI = 79.5, 82.4) opposed public marijuana smoking. Correlates of favoring public marijuana smoking included being male, younger (Ps < 0.01), black or Hispanic, past‐month tobacco and/or marijuana users and perceiving no/low harm from marijuana SHS (Ps < 0.0001). Conclusion: While one in four US adults report recent marijuana second‐hand smoke exposure, a majority believe marijuana second‐hand smoke is harmful and most oppose public marijuana smoking. [ABSTRACT FROM AUTHOR]

Background and Aims: Cannabis products are becoming increasingly diverse, and vary considerably in concentrations of ∆9‐tetrahydrocannabinol (THC) and cannabidiol (CBD). Higher doses of THC can increase the risk of harm from cannabis, while CBD may partially offset some of these effects. Lower Risk Cannabis Use Guidelines currently lack recommendations based on quantity of use, and could be improved by implementing standard units. However, there is currently no consensus on how units should be measured or standardized among different cannabis products or methods of administration. Argument Existing proposals for standard cannabis units have been based on specific methods of administration (e.g. joints) and these may not capture other methods, including pipes, bongs, blunts, dabbing, vaporizers, vape pens, edibles and liquids. Other proposals (e.g. grams of cannabis) cannot account for heterogeneity in THC concentrations among different cannabis products. Similar to alcohol units, we argue that standard cannabis units should reflect the quantity of primary active pharmacological constituents (dose of THC). On the basis of experimental and ecological data, public health considerations and existing policy, we propose that a 'standard THC unit' should be fixed at 5 mg THC for all cannabis products and methods of administration. If supported by sufficient evidence in future, consumption of standard CBD units might offer an additional strategy for harm reduction. Conclusions: Standard ∆9‐tetrahydrocannabinol (THC) units can potentially be applied among all cannabis products and methods of administration to guide consumers and promote safer patterns of use. [ABSTRACT FROM AUTHOR]

Background and aims: Young adult college students in the United States are likely to be affected by marijuana liberalization trends. However, changes in students' marijuana use following recreational marijuana legalization (RML) have not been examined in more than one RML state at a time, or beyond 1–2 years post‐legalization. Design Cross‐sectional National College Health Assessment survey administered twice yearly from 2008 to 2018. Setting: A total of 587 4‐year colleges and universities in 48 US states. Participants: Undergraduates aged 18–26 years attending college in US states that did (n = 234 669 in seven states) or did not (n = 599 605 in 41 states) enact RML between 2008 and 2018. Measurements Self‐reported marijuana use (past 30 days) and individual and contextual covariates, institution‐provided institutional and community covariates and publicly available dates when states enacted RML. Findings Adjusting for covariates, state differences and state‐specific linear time trends (accounting for pre‐RML trends), prevalence of 30‐day marijuana use increased more among students exposed to RML [odds ratio (OR) = 1.23, 95% confidence interval (CI) = 1.19–1.28, P < 0.001] than among non‐RML state students throughout the same time‐period; the results were similar for frequent use (≥ 20 days) (OR = 1.18, 95% CI = 1.10–1.27, P < 0.001). Interaction models supported stronger RML effects among students who were female, residing off‐campus and aged 21 years and older; sexual orientation did not moderate RML effects. In the earliest states to enact RML (2012) there were increases in use prevalence in the second through the sixth year post‐RML compared to pre‐RML. In the second legalization group (2015) there were increases in the first and second year post‐RML, and greater increases in the third year. In the later states (2016–17), increases were observed in both years after RML. Conclusions: In US states that enacted recreational marijuana legislation from 2012 to 2017 there was evidence for a general trend towards greater increases in marijuana use by college students and differential impact by gender, legal using age and campus residence. [ABSTRACT FROM AUTHOR]

Background andAims: The commodity purchase task is a simulated demand procedure that is easy and quick to complete (< 5 minutes) as well as adaptable for remote delivery and use with varied study populations. The purpose of this meta‐analysis was to synthesize research using the commodity purchase task with illicit substances to evaluate the magnitude of omnibus effects sizes and moderators of the correlation of demand indices with quantity–frequency (QF) and severity measures. Design Random‐effects meta‐analyses and meta‐regressions involving studies with cross‐sectional correlational designs. Setting and Participants: Eleven studies, 10 outcomes and 2146 participants from two countries (USA and UK) published up to 1 October 2018. Measurements Omnibus effect sizes (correlation coefficients) of five demand indices from the commodity purchase task [intensity (unconstrained consumption), elasticity (price sensitivity), Omax (maximum expenditure), Pmax (price at maximum expenditure) and breakpoint (first price of zero consumption)] with QF and severity measures. Meta‐regression models tested moderators of effect sizes (i.e. sample age and sex composition, commodity type and number of prices used in the commodity purchase task). Findings Significant omnibus effect sizes were observed with QF and severity measures for intensity (r = 0.32/0.28, QF/severity, respectively), elasticity (r = −0.14/−0.18), Omax (r = 0.30/0.29) and breakpoint (r = 0.17/0.22) values. Pmax was only significantly associated with severity measures (r = 0.15). The percentage of female participants and number of prices used in the purchase task significantly moderated Pmax and breakpoint effect‐size estimates in that stronger associations were observed in samples with a greater percentage of women and in studies using tasks with more price points. Commodity type (cannabis versus cocaine) did not significantly moderate associations involving any demand index. Conclusions: Behavioral economic demand as measured by the commodity purchase task is consistently correlated with measures of illicit substance use quantity–frequency and severity. [ABSTRACT FROM AUTHOR]

Aims: We aimed to investigate whether or not a diagnosis of schizophrenia increases the risk of a substance abuse diagnosis. Design Prospective cohort study using a longitudinal study design. Setting and participants: Individuals born in Denmark from 1955 to 1999 and registered in the Danish registers between 1 January 1968 and 1 July 2013. Measurements: We investigated the associations between schizophrenia and ICD diagnoses of substance abuse, both established through various Danish registers. The Cox regression model was used and adjusted for calendar year, gender, urbanicity, co‐abuse, other psychiatric diagnoses, parents' substance abuse and psychiatric history, parents' immigration and parents' socio‐economic position. Individuals diagnosed with substance abuse less than a year after diagnosis of schizophrenia were classified as not diagnosed with schizophrenia. Findings The cohort consisted of 3 133 968 individuals. During follow‐up (103 212 328 person‐years at risk), a total of 14 007 individuals developed schizophrenia, with 2885 subsequently diagnosed with substance abuse. A diagnosis of schizophrenia was positively associated with the risk of developing substance abuse [hazard ratio (HR) = 3.69, 95% confidence interval (CI) = 3.56–3.83]. Additionally, adjusting for a co‐abuse markedly affected the associations, making schizophrenia primarily associated with an increased risk of abuse of cannabis, alcohol, stimulants and other substances (adjusted HR = 2.48, 95% CI = 2.34–2.64 for cannabis; HR = 1.94, 95% CI = 1.87–2.02 for alcohol; HR = 1.77, 95% CI = 1.61–1.95 for stimulants; HR = 1.36, 95% CI = 1.20–1.54 for other substances). The association was still significant 10–15 years subsequent a diagnosis of schizophrenia (HR = 2.50, 95% CI = 2.26–2.76). Conclusions: In Denmark a diagnosis of schizophrenia is significantly associated with increased risk of subsequent diagnosis of substance abuse. [ABSTRACT FROM AUTHOR]

The article discusses a study by D. T. Myran and colleagues which reported on changes in cannabis related emergency department (ED) attendances in Ontario across a period of major policy change in Canada. Topics include the time periods that were included in the study, factors that may explain the rapidly increasing rate of ED attendances in the two years before legalization, and the most important oversight by the authors regarding the pre-legalization phase.

Commentary to: Understanding and learning from the diversification of cannabis supply laws [ABSTRACT FROM AUTHOR]

To understand the aetiology of cannabis use disorder, risk trajectory classes need to be combined with knowledge of cannabis exposure, contextual factors surrounding cannabis use and consideration of the role of genetics. [ABSTRACT FROM AUTHOR]

Aims: To perform a wastewater‐based analysis to explore the impact of newly legalized retail cannabis sales on its use and to determine if this approach could estimate the size of the legal market place, which began 1 August 2014 in the study area. Design Laboratory study of raw wastewater samples collected and analyzed over the 3‐year period from 2014 to 2016. Setting and Participants: Samples obtained from the two wastewater treatment plants that serviced a municipality of 200 000 people in the state of Washington, USA. Measurements Quantitative analysis of 24‐hour composite influent samples for the metabolite of the active ingredient in cannabis, 11‐nor‐9‐Carboxy‐Δ9‐tetrahydrocannabinol (THC‐COOH) were performed by liquid chromatography coupled to mass spectrometry. Findings Wastewater estimates for THC‐COOH increased by 9% per quarter, suggesting a doubling in cannabis consumption from 1 December 2013 to 31 December 2016. State‐sold THC increased at nearly 70% per quarter, while stores operated from 1 August 2014 to 31 December 2016. Estimating the proportion of the total cannabis market supplied by state‐regulated cannabis from these data is not currently achievable. Conclusion: A wastewater‐based measure of cannabis consumption suggests a significant increase in consumption in Washington, USA following legalization, and that legal sales appear to have displaced a large portion of the illicit market. [ABSTRACT FROM AUTHOR]

The article discusses the Indian Hemp Drugs Commission report from 1894, which recommends the regulation and taxation of cannabis, rather than the prohibition. The report found that excessive ganja use could cause psychosis in rare instances and suggested regulation and taxation to limit excessive use and allow for medical use, preventing the growth of an illicit cannabis market.

Aims: To quantify changes in (i) potency (concentration of Δ9‐tetrahydrocannabinol; %THC), (ii) price (euros/g of cannabis) and (iii) value (mg THC/euro) of cannabis resin and herbal cannabis in Europe. Design Repeated cross‐sectional study. Setting and participants: Data collected from 28 European Union (EU) member states, Norway and Turkey by the European Monitoring Centre for Drugs and Drug Addiction. Measurements Outcome variables were potency, price and value for cannabis resin and herbal cannabis in Europe, 2006–16. Inflation was estimated using the Harmonised Indices of Consumer Prices. Mixed‐effects linear regression models were used to estimate linear and quadratic time trends, with a random intercept and slope fitted to account for variation across countries. Findings Resin potency increased from a mean [95% confidence interval (CI)] of 8.14% THC (6.89, 9.49) in 2006 to 17.22 (15.23, 19.25) in 2016. Resin price increased from 8.21 euros/g (7.54, 8.97) to 12.27 (10.62, 14.16). Resin increased in value, from 11.00 mg THC per euro (8.60, 13.62) to 16.39 (13.68, 19.05). Quadratic time trends for resin potency and value indicated minimal change from 2006 to 2011, followed by marked increases from 2011 to 2016. Herbal cannabis potency increased from 5.00% THC (3.91, 6.23) to 10.22 (9.01, 11.47). Herbal price increased from 7.36 euros/g (6.22, 8.53) to 12.22 (10.59, 14.03). The value of herbal cannabis did not change from 12.65 mg of THC per euro (10.18, 15.34) to 12.72 (10.73, 14.73). All price trends persisted after adjusting for inflation. Conclusions: European cannabis resin and herbal cannabis increased in potency and price from 2006 to 2016. Cannabis resin (but not herbal cannabis) increased in the quantity of Δ9‐tetrahydrocannabinol per euro spent. Marked increases in resin potency and value from 2011 to 2016 are consistent with the emergence of new resin production techniques in European and neighbouring drug markets. [ABSTRACT FROM AUTHOR]

Background and aims: The World Health Organization's (WHO's) proposed International Classification of Diseases, 11th edition (ICD‐11) includes several major revisions to substance use disorder (SUD) diagnoses. It is essential to ensure the consistency of within‐subject diagnostic findings throughout countries, languages and cultures. To date, agreement analyses between different SUD diagnostic systems have largely been based in high‐income countries and clinical samples rather than general population samples. We aimed to evaluate the prevalence of, and concordance between diagnoses using the ICD‐11, The WHO's ICD 10th edition (ICD‐10) and the Diagnostic and Statistical Manual of Mental Disorders, 4th and 5th editions (DSM‐IV, DSM‐5); the prevalence of disaggregated ICD‐10 and ICD‐11 symptoms; and variation in clinical features across diagnostic groups. Design Cross‐sectional household surveys. Setting: Representative surveys of the general population in 10 countries (Argentina, Australia, Brazil, Colombia, Iraq, Northern Ireland, Poland, Portugal, Romania and Spain) of the World Mental Health Survey Initiative. Participants: Questions about SUDs were asked of 12 182 regular alcohol users and 1788 cannabis users. Measurements Each survey used the World Mental Health Survey Initiative version of the WHO Composite International Diagnostic Interview version 3.0 (WMH‐CIDI). Findings Among regular alcohol users, prevalence (95% confidence interval) of life‐time ICD‐11 alcohol harmful use and dependence were 21.6% (20.5–22.6%) and 7.0% (6.4–7.7%), respectively. Among cannabis users, 9.3% (7.4–11.1%) met criteria for ICD‐11 harmful use and 3.2% (2.3–4.0%) for dependence. For both substances, all comparisons of ICD‐11 with ICD‐10 and DSM‐IV showed excellent concordance (all κ ≥ 0.9). Concordance between ICD‐11 and DSM‐5 ranged from good (for SUD and comparisons of dependence and severe SUD) to poor (for comparisons of harmful use and mild SUD). Very low endorsement rates were observed for new ICD‐11 feature for harmful use ('harm to others'). Minimal variation in clinical features was observed across diagnostic systems. Conclusions: The World Health Organization's proposed International Classification of Diseases, 11th edition (ICD‐11) classifications for substance use disorder diagnoses are highly consistent with the ICD 10th edition and the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM‐IV). Concordance between ICD‐11 and the DSM 5th edition (DSM‐5) varies, due largely to low levels of agreement for the ICD harmful use and DSM‐5 mild use disorder. Diagnostic validity of self‐reported 'harm to others' is questionable. [ABSTRACT FROM AUTHOR]

Abstract: Aims: This review provides an up‐to‐date curated source of information on alcohol, tobacco and illicit drug use and their associated mortality and burden of disease. Limitations in the data are also discussed, including how these can be addressed in the future. Methods: Online data sources were identified through expert review. Data were obtained mainly from the World Health Organization, United Nations Office on Drugs and Crime and Institute for Health Metrics and Evaluation. Results: In 2015, the estimated prevalence among the adult population was 18.4% for heavy episodic alcohol use (in the past 30 days); 15.2% for daily tobacco smoking; and 3.8, 0.77, 0.37 and 0.35% for past‐year cannabis, amphetamine, opioid and cocaine use, respectively. European regions had the highest prevalence of heavy episodic alcohol use and daily tobacco use. The age‐standardized prevalence of alcohol dependence was 843.2 per 100 000 people; for cannabis, opioids, amphetamines and cocaine dependence it was 259.3, 220.4, 86.0 and 52.5 per 100 000 people, respectively. High‐income North America region had among the highest rates of cannabis, opioid and cocaine dependence. Attributable disability‐adjusted life‐years (DALYs) were highest for tobacco smoking (170.9 million DALYs), followed by alcohol (85.0 million) and illicit drugs (27.8 million). Substance‐attributable mortality rates were highest for tobacco smoking (110.7 deaths per 100 000 people), followed by alcohol and illicit drugs (33.0 and 6.9 deaths per 100 000 people, respectively). Attributable age‐standardized mortality rates and DALYs for alcohol and illicit drugs were highest in eastern Europe; attributable age‐standardized tobacco mortality rates and DALYs were highest in Oceania. Conclusions: In 2015 alcohol use and tobacco smoking use between them cost the human population more than a quarter of a billion disability‐adjusted life years, with illicit drugs costing further tens of millions. Europeans suffered proportionately more, but in absolute terms the mortality rate was greatest in low‐ and middle‐income countries with large populations and where the quality of data was more limited. Better standardized and rigorous methods for data collection, collation and reporting are needed to assess more accurately the geographical and temporal trends in substance use and its disease burden. [ABSTRACT FROM AUTHOR]