Cannabis-related Harms Research Articles

The impact of cannabis legalization for recreational purposes: The Canadian experience

AbstractCannabis Legalization for Recreational Purposes took place in Canada in October 2018. One of the federal government’s stated goals with this legalization was to protect Canadian youth from cannabis-related harms. The Canadian model differs from other jurisdictions that legalized recreational cannabis use, especially with regard to a higher degree of government regulation of the cannabis market. Another difference is the development and endorsement of lower-risk cannabis use guidelines to educate the public and health professionals. Here, we will present the changes in the regulation of the Canadian cannabis market. We will also present some changes in the epidemiology and parameters of cannabis use (modes of use, potency of cannabis) among adults and youths. Although it is clear that prevalence of use has increased in some groups (notably older adults), results for youth are mixed, with the majority of studies showing no pronounced increase. A trend of a decrease in youth cannabis use seen pre-legalization may have reversed. Data about changes in the age of initiation, the influence of legalization on sex and gender, and race/ ethnicity are limited, with evidence suggesting that the age of initiation slightly increased and the prevalence of use has become more similar between females and males. The development and utility of the lower-risk cannabis use guidelines will be also presented.Disclosure of InterestB. Le Foll Grant / Research support from: . Dr. Le Foll has in-kind donations of cannabis products from Aurora Cannabis Enterprises Inc. . Dr. Le Foll has obtained industry funding from Canopy Growth Corporation (through research grants handled by the Centre for Addiction and Mental Health and the University of Toronto)

What is the hype on #MedicinalCannabis in the United States? A content analysis of medicinal cannabis tweets.

Medicinal cannabis is now legal in 44 US jurisdictions. Between 2020 and 2021 alone, four US jurisdictions legalised medicinal cannabis. The aim of this study is to identify themes in medicinal cannabis tweets from US jurisdictions with different legal statuses of cannabis from January to June 2021. A total of 25,099 historical tweets from 51 US jurisdictions were collected using Python. Content analysis was performed on a random sample of tweets accounting for the population size of each US jurisdictions (n=750). Results were presented separately by tweets posted from jurisdictions where all cannabis use (non-medicinal and medicinal) is 'fully legalised', 'illegal' and legal for 'medical-only' use. Four themes were identified: 'Policy', 'Therapeutic value', 'Sales and industry opportunities' and 'Adverse effects'. Most of the tweets were posted by the public. The most common theme was related to 'Policy' (32.5%-61.5% of the tweets). Tweets on 'Therapeutic value' were prevalent in all jurisdictions and accounted for 23.8%-32.1% of the tweets. Sales and promotional activities were prominent even in illegal jurisdictions (12.1%-26.5% of the tweets). Fewer than 10% of tweets were about intoxication and withdrawal symptoms. This study has explored if content themes of medicinal cannabis tweets differed by cannabis legal status. Most tweets were pro-cannabis and they were related to policy, therapeutic value, and sales and industry opportunities. Tweets on unsubstantiated health claims, adverse effects and crime warrants continued surveillance as these conversations could allow us to estimate cannabis-related harms to inform health surveillance.

Deterrence effect of penalties upon adolescent cannabis use.

Penalties are used in an effort to curtail drug use by citizens in most societies. There are growing calls for a reduction or elimination of such penalties. Deterrence theory suggests that use should increase if penalties reduce and vice versa. We sought to examine the relationship between changes to penalties for drug possession and adolescent cannabis use. Ten instances of penalty change occurred in Europe between 2000 and 2014, seven of which involved penalty reduction and three involved penalty increase. We conducted a secondary analysis of a series of cross-sectional surveys of 15-16-year-old school children, the ESPAD surveys, which are conducted every four years. We focused on past month cannabis use. We anticipated that an eight-year time span before and after each penalty change would yield two data points either side of the change. A simple trend line was fitted to the data points for each country. In eight cases, the trend slope in past month cannabis use was in the direction predicted by deterrence theory, the two exceptions being the UK policy changes. Using the principals of binomial distributions, the likelihood of this happening by chance is 56/1024 = 0.05. The median change in the baseline prevalence rate was by 21%. The science seems far from settled on this issue. There remains a distinct possibility that reducing penalties could contribute to small increases in adolescent cannabis use and consequently increase cannabis-related harms. This possibility should be considered in any political decision-making influencing drug policy changes.

How should policymakers regulate the tetrahydrocannabinol content of cannabis products in a legal market?

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.

Early-onset smoking and vaping of cannabis: Prevalence, correlates and trends in New Zealand 14-15-year-olds.

Initiating cannabis use at an early age elevates risk of harm. Cannabis vaping is an emerging issue, and it is unknown whether the patterning and correlates of early-onset cannabis vaping differ from those of cannabis smoking. We used repeat cross-sectional data from a nationally representative biennial survey (2012-2018) of students aged 14-15 years in New Zealand (N=11,405), response rate 65% (2012), 64% (2014-2016) and 59% (2018). Between 2012 and 2018 lifetime cannabis use decreased, but regular use (past month, weekly, daily) was stable. Prevalence of past month, weekly and daily use in 2016-2018 (pooled) was 8.6%, 3.4% and 1.5%, respectively. Cannabis vaping was reported by 24% of past month cannabis users. The demographic profile of early-onset cannabis smokers and vapers was similar, with elevated use of both modes among Māori (Indigenous), same- or both-sex attracted students and those in low decile (high-deprivation) schools. Correlates were similar for both modes. Cannabis use was strongly associated with tobacco and alcohol use. The next strongest associations (after adjustment) were exposure to second-hand smoke at home, student income >$50/week and low parental monitoring of whereabouts. Past week social media use, psychological distress and low parental monitoring of spending were also associated with both modes. Early-onset cannabis use is much higher in structurally disadvantaged groups, and among those who use tobacco and alcohol. Comprehensive multisubstance approaches to prevention are indicated in this age group. Efforts to reduce socio-economic inequity and exposure to other risk factors may reduce cannabis-related harm.

Adult use of highly-potent Δ9-THC cannabis concentrate products by U.S. state cannabis legalization status, 2021

BackgroundCompared to plant/flower cannabis products, cannabis concentrates have higher average potency of delta-9-tetrahydrocannabinol (Δ9-THC), which may be associated with greater likelihood of cannabis-related harms. Information on factors associated with use of cannabis concentrates is needed. MethodsRespondents were 4,328 adult past-7-day cannabis users from all 50 U.S. states and Washington DC (DC) who participated in an online 2021 survey. Using logistic regression to generate adjusted odds ratios (aOR), we investigated whether participants in states that enacted recreational cannabis laws (RCL, 12 states plus DC [treated as a state], n = 1,236) or medical cannabis laws (MCL-only, 23 states, n = 2,030) by December 31, 2020 were more likely than those in states without cannabis laws (no-CL, 15 states, n = 1,062) to use cannabis concentrate products in the prior 7 days. ResultsMost participants (92.4%) used plant material in the prior 7 days; 57.0% used cannabis concentrates. In RCL, MCL and no-CL states, concentrate use was reported by 61.5%, 56.6%, and 52.5%, respectively. Compared to participants in no-CL states, odds of using cannabis concentrate products were greater among those in RCL states (aOR = 1.47; CI = 1.17–1.84) and MCL-only states (aOR = 1.29; CI = 1.08–1.55). Whether states had legally-authorized dispensaries had little effect on results. ConclusionResults suggest that individuals in MCL-only and RCL states are more likely to use cannabis concentrate products. Determining mechanisms underlying these results, e.g., commercialization, could provide important information for prevention. Clinicians should be alert to patient use of concentrates, especially in MCL-only and RCL states. Continued monitoring is warranted as additional states legalize cannabis use.

Savoring as an intervention for cannabis use: acceptability, feasibility, and preliminary results

Although savoring appears protective against cannabis problems, researchers have yet to apply it to reduce cannabis-related harms. Study I surveyed a large (N = 557, M age = 36.9, 50.1% Male, 73% White) sample who rated a hypothetical savoring intervention as feasible and acceptable; those who savored more reported fewer cannabis problems, less use, and less intoxication. Study II, a pilot experiment (N = 26, M age = 18, 34.6% Male, 42% White), randomly assigned participants to either a week-long savoring intervention (n = 15) or control group (n = 11). Savorers reported moderate to large decreases across time in cannabis use, amount consumed, and intoxication as well as increases in happiness and negative cannabis expectancies. Both studies suggest that savoring can reduce use and protect against negative outcomes. These preliminary findings suggest that further work to examine the efficacy of savoring as an intervention for substance use appears warranted.

Associations between recreational cannabis legalization and cannabis-related emergency department visits by age, gender, and geographic status in Ontario, Canada: An interrupted time series study.

Legalization of recreational cannabis in Ontario included the legalization of flower and herbs (Phase 1, October 2018), and was followed by the deregulation of cannabis retailers and sales of edibles (Phase 2, February 2020). Research on the impact of cannabis legalization on acute care utilization is nascet; no research has investigated potential age, gender, and geographically vulnerable subgroup effects. Residents living in Northern Ontario not only have higher levels of substance use problems, but also have inadequate access to primary healthcare. Our study investigated the impact of Ontario's recreational cannabis policy (including Phase 1 and 2) on cannabis-attributable emergency department (ED) visits, and estimated the impact separately for different age and gender groups, with additional analyses focused on Northern Ontarians. We created a cohort of adults (18 and over) eligible for provincial universal health insurance with continuous coverage from 2015-2021 (n = 14,900,820). An interrupted time series was used to examine the immediate impact and month-to-month changes in cannabis-related ED visits associated with Phase 1 & 2 for each subgroup. While Northern Ontario has higher rates of cannabis-related ED visits, both Northern and Southern Ontario show similar patterns of changes. Phase 1 was associated with significant increases in adults 25-64, with the strongest increases seen in women 45-64. Month-to-month trends were flattened in most groups compared to pre-legalization. Phase 2 was associated with significant immediate increases for adults aged 18-44 in both genders, but the increases were larger in women than men. No significant month-to-month changes were detected in this period. While current preventive efforts are largely focused on reducing cannabis-related harms in youths and younger adults, our results show that adults 25-64, particularly women, have been significantly impacted by cannabis policies. Further research on gender-specific cannabis dosage and targeted interventions for adult women should be investigated. Legalization did not appear to have a differential impact on Northern versus Southern Ontario, but higher rates of ED visits in the North should be addressed.

Association Between Markers of Vulnerability for Cannabis-Related Harms and Source of Supply: Secondary Analysis of a Representative Population Survey.

In 2018, the sale of non-medical cannabis was authorized in the province of Quebec in Canada, within a public monopoly under the Société Québécoise du Cannabis (SQDC). The objective of this study was to offer a description of the cannabis-using population regarding the sources of cannabis supply and to explore whether at-risk individuals are purchasing cannabis at SQDC. We used data from a cross-sectional, representative population survey (age >18 years, n = 1799), the Enquête Québécoise sur le Cannabis, which was completed between February and June 2019. Analyses involved adjusted binary logistic regressions, incorporating population weights, to assess 7 potential indicators of harm. The vulnerability profiles of SQDC consumers (47.8%) and those acquiring their cannabis elsewhere (52.2%) were similar in terms of frequency of cannabis use (adjusted odds ratio [aOR] = 0.46; 95% confidence interval [CI] = 0.12-1.67), motivation to use (aOR = 0.62; 95% CI = 0.16-2.46), concomitant consumption of other substances (aOR = 0.80; 95% CI = 0.14-4.75), cannabis-impaired driving behaviours (aOR = 0.93; 95% CI = 0.26-3.36), psychological distress (aOR = 0.99; 95% CI = 0.26-3.79), and problematic cannabis use (aOR = 0.46; 95% CI = 0.13-1.64). However, SQDC consumers were more likely to be aware of the cannabinoid content of the product purchased compared to those who acquired their cannabis from other sources (aOR = 4.12; 95% CI = 1.10-15.40). No association was detected between the source of cannabis supply and potential vulnerability indicators of cannabis-related harms, but SQDC consumers were more aware of the cannabinoid content of the products purchased. These results suggest that the regulated government supply in Quebec is reaching a substantial portion of those with potential high vulnerability to harm. Whether this knowledge translates into a reduction in the negative consequences related to consumption is still to be determined.

The impact of cannabis legalization for recreational purposes on youth: A narrative review of the Canadian experience.

Cannabis legalization for non-medical purposes (subsequently referred to as “cannabis legalization” or “legalization”) took place in Canada in October 2018. One of the federal government's stated goals with cannabis legalization was to protect Canadian youth from cannabis-related harms. The main objective of this narrative review is to describe the impact of cannabis legalization on Canadian youth. To that end, we discuss the regulation of the Canadian cannabis market, outline changes in the epidemiology and parameters of cannabis use (modes of use, potency of cannabis) among youth, and discuss prevention and education initiatives related to cannabis. The Canadian model differs from other jurisdictions that legalized recreational cannabis use, especially with regard to a higher degree of government regulation of the cannabis market. Another difference is the development and endorsement of lower-risk cannabis use guidelines to educate the public and health professionals. The results available for this review cover only 3 years post-legalization. Cannabis legalization in Canada brought an apparent increase in use among Canadian older than 25. However, results for youth are mixed, with the majority of studies showing no pronounced increase. Notably, the trend of a decrease in adolescents' cannabis use seen pre-legalization may have reversed. Emerging evidence also suggests that cannabis-related hospitalizations and emergency department visits among Canadian youth may have increased due to cannabis legalization. Data about changes in the age of initiation, the influence of legalization on sex and gender, and race/ethnicity are limited, with evidence suggesting that the age of initiation slightly increased. So far, there is limited data about the impact of cannabis legalization on Canadian youth. Further long-term monitoring and research to assess the effects of cannabis legalization on Canadian youth.

Trends in Cannabis Polysubstance Use During Early Pregnancy Among Patients in a Large Health Care System in Northern California

Rates of prenatal cannabis use are increasing alongside perceptions that cannabis is a harmless therapeutic for pregnancy-related ailments, while rates of prenatal use of alcohol and tobacco are decreasing. It is important to examine whether cannabis use during pregnancy is increasing similarly among patients with and patients without co-occurring substance use. To examine trends in cannabis polysubstance use during pregnancy and to test differences in cannabis use over time among pregnant individuals who use only cannabis vs those who use cannabis and other substances. This cross-sectional time-series study used data from 367 138 pregnancies among 281 590 unique pregnant patients universally screened for prenatal substance use as part of standard care in Kaiser Permanente Northern California from January 1, 2009, to December 31, 2018. Statistical analysis was performed from October 5, 2021, to April 18, 2022. Time (calendar year). Use of substances during early pregnancy was assessed via universal screening with a self-administered questionnaire (for cannabis, alcohol, stimulants, and nicotine) and/or positive results of a urine toxicology test (for cannabis, alcohol, stimulants, and pharmaceutical opioids), and data were extracted from the electronic health record. The study sample of 367 138 pregnancies from 281 590 unique pregnant patients (median gestation at time of screening, 8.6 weeks [IQR, 7.3-10.6 weeks]) was 25.9% Asian or Pacific Islander, 6.6% Black, 25.8% Hispanic, 38.0% non-Hispanic White, and 3.6% other race or ethnicity; 1.1% were aged 11 to 17 years, 14.9% were aged 18 to 24 years, 61.9% were aged 25 to 34 years, and 22.1% were aged 35 years or older; and the median neighborhood household income was $70 455 (IQR, $51 563-$92 625). From 2009 to 2018, adjusted rates of use of only cannabis during pregnancy (no other substances) increased substantially from 2.39% (95% CI, 2.20%-2.58%) in 2009 to 6.30% (95% CI, 6.00%-6.60%) in 2018, increasing at an annual relative rate of 1.11 (95% CI, 1.10-1.12). The rate of use of cannabis and 1 other substance also increased (annual relative rate, 1.04 [95% CI, 1.03-1.05]), but not as rapidly (P < .001 for difference), while the rate of use of cannabis and 2 or more other substances decreased slightly (annual relative rate, 0.97 [95% CI, 0.96-0.99]). Adjusted rates of prenatal use of cannabis and alcohol (1.04 [95% CI, 1.03-1.06]) and cannabis and stimulants (1.03 [95% CI, 1.01-1.06]) increased over time, while rates of prenatal use of cannabis and nicotine (0.97 [95% CI, 0.96-0.98]) decreased. In this cross-sectional time-series study, rates of prenatal cannabis use during early pregnancy increased significantly more rapidly among patients without co-occurring substance use, which could reflect increased acceptability of cannabis and decreased perceptions of cannabis-related harms. Furthermore, increased rates of use of cannabis with alcohol and stimulants warrant continued monitoring.

Cannabis Induced Psychosis

Even if most people use cannabis without many negative consequences, some experience cannabis related harms. At higher levels of intake, one of these harms could be psychotic symptoms and even cannabis-induced psychosis. During the last years, we have seen increased treatment seeking for cannabis use disorders in Europe. Parallel with this increase we have seen an increase in the incidence of cannabis induced psychosis in all Scandinavian countries and an increased population attributable fraction for cannabis on the prevalence of schizophrenia has been demonstrated. All this may reflect increased use of cannabis, but more likely increased content of D9-tetrahydrocannabinol (THC) is most cannabis products. Many have also pointed to the fact that we have seen an increase in the incidence of schizophrenia in the same period, maybe attributable to cannabis use. If we also take into consideration that up to one third of those with cannabis-induced psychosis over time receive a diagnosis of schizophrenia, we may see at least two implications. Firstly, these findings strengthens the evidence for a causative relationship between cannabis use and schizophrenia, a causative relationship that man have suggested for several years, but that has had some opponents. Secondly, it points to cannabis-induced psychosis should be considered to be a part of the ICD-10 F2-chapter rather than the F1-chapter. This may be true also for the other substance-induced psychosis (F1x.5). An additional argument for this is that for no other psychotic diagnosis, a precipitation factor is mentioned in the diagnosis.DisclosureNo significant relationships.

Reflective and non-reflective influences on cannabis use among undergraduate students: A qualitative study

Objective Around 40% of US university students use cannabis, 25% of whom present with cannabis use disorder, which endangers health. We investigated the concurrent contribution of reflective processes, which generate action via conscious deliberation, and non-reflective processes, which prompt behavior automatically, to undergraduates’ cannabis consumption. Participants Eighteen UK undergraduates who regularly consume cannabis (11 female, 7 male; mean age 20 y). Methods Semi-structured interviews explored cannabis motives, routines, cues, and decision points. Thematic analysis identified themes, in each of which reflective and non-reflective dimensions were coded. Results Four themes were identified: cannabis use for relaxation, social bonding, and symbolic-affective significance, and contexts and triggers. Some influences guided cannabis use reflectively in some settings, and non-reflectively in others. Even when cannabis use was consciously driven, non-reflective processes were deployed to execute subservient acts, such as rolling joints. Conclusions Findings highlight specific processes and pathways that might be targeted to reduce cannabis-related harm.

A Clinical Framework for Evaluating Cannabis Product Quality and Safety.

Increase in medical cannabis use, along with available products, warrants the need for clinicians to be knowledgeable in evaluating the quality of any cannabis product presented in clinical practice. Determining whether a product is regulated within the region is key in assessing overall quality and safety. Regulated products are held to a higher standard including independent testing, contamination mitigation, and concentration limits. Here, we present a clinical framework in evaluating cannabis products to ascertain the quality and regulation level of the product. Evaluation includes assessing the source company, reviewing product details (e.g., type, cannabinoid content, and labeling), and assessing quality control variables such as manufacturing and decontamination processes. The quality of products patients use is an important part of mitigating cannabis-related harms, especially in medically vulnerable patients. Currently, there is a great need to implement widespread standardization and regulations to ensure product quality and safety.

Review of cannabis use among Aboriginal and Torres Strait Islander people

The health effects of cannabis use may not always be seen as a high priority for Aboriginal and Torres Strait Islander communities. However, the impact of cannabis use on physical and mental health can have significant consequences. It is known that the use of high potency cannabis has increased over the last two decades, with a corresponding increased risk to health. In particular, young people are at increased risk of experiencing harms to mental health. Physical harms to health include effects on the respiratory system, cardiovascular system, an increased risk of cancer, and in-utero effects from maternal use. The review notes concern that in countries where there has been commercialisation of cannabis use, there has been an increase in the rate and use of high potency products. While generalising findings about cannabis use for Aboriginal and Torres Strait Islander people is problematic due to limited data, high rates of cannabis use have been found in some remote communities. The review highlights the protective factors that reduce harms from cannabis use and suggests future directions for a collaborative approach to addressing cannabis related harms in communities. This review is part of a suite of knowledge exchange products that includes a summary, a video, and a fact sheet.

Lower-Risk Cannabis Use Guidelines (LRCUG) for reducing health harms from non-medical cannabis use: A comprehensive evidence and recommendations update.

Cannabis use is common, especially among young people, and is associated with risks for various health harms. Some jurisdictions have recently moved to legalization/regulation pursuing public health goals. Evidence-based 'Lower Risk Cannabis Use Guidelines' (LRCUG) and recommendations were previously developed to reduce modifiable risk factors of cannabis-related adverse health outcomes; related evidence has evolved substantially since. We aimed to review new scientific evidence and to develop comprehensively up-to-date LRCUG, including their recommendations, on this evidence basis. Targeted searches for literature (since 2016) on main risk factors for cannabis-related adverse health outcomes modifiable by the user-individual were conducted. Topical areas were informed by previous LRCUG content and expanded upon current evidence. Searches preferentially focused on systematic reviews, supplemented by key individual studies. The review results were evidence-graded, topically organized and narratively summarized; recommendations were developed through an iterative scientific expert consensus development process. A substantial body of modifiable risk factors for cannabis use-related health harms were identified with varying evidence quality. Twelve substantive recommendation clusters and three precautionary statements were developed. In general, current evidence suggests that individuals can substantially reduce their risk for adverse health outcomes if they delay the onset of cannabis use until after adolescence, avoid the use of high-potency (THC) cannabis products and high-frequency/-intensity of use, and refrain from smoking-routes for administration. While young people are particularly vulnerable to cannabis-related harms, other sub-groups (e.g., pregnant women, drivers, older adults, those with co-morbidities) are advised to exercise particular caution with use-related risks. Legal/regulated cannabis products should be used where possible. Cannabis use can result in adverse health outcomes, mostly among sub-groups with higher-risk use. Reducing the risk factors identified can help to reduce health harms from use. The LRCUG offer one targeted intervention component within a comprehensive public health approach for cannabis use. They require effective audience-tailoring and dissemination, regular updating as new evidence become available, and should be evaluated for their impact.

Non-medical cannabis use: international policies and outcomes overview. An outline for Portugal.

Introduction Cannabis is probably the most commonly used illicit drug. It is often regarded as a relatively nonharmful experience, even though evidence indicates otherwise. Legalization of non-medical cannabis, which has already taken place in several countries, is currently a controversial issue.Objective To provide an up-to-date overview of current models and policies and their outcomes that can inform future political decisions regarding non-medical cannabis use.Methods PubMed/MEDLINE and Google Scholar scientific databases were searched for articles written in English, Spanish, and Portuguese published between 1990 and December 2020. The reference lists of these articles were similarly used as bibliography sources. Gray literature was also included.Results While non-medical cannabis has been decriminalized in many countries, it has only been legalized in Uruguay, Canada, and some U.S. states. Several benefits of legalization were identified: decreases in cannabis-related crimes, law-enforcement and judicial costs; reduction in synthetic cannabis supply; decline in black economies and possible diminution of other illegal drug buying; and tax revenue increases. Reported legalization problems included: increases in cannabis use; cannabis-related disorders; and cannabis-related accidents and hospitalizations. Harm-reduction strategies are available in the scientific literature.Conclusion Growing, although incomplete, evidence exists to guide policy makers, minimize cannabis-related harm, and positively contribute to public health, if the legalization path is to be followed. Dialogue between legislators and science should be encouraged. There are more than a few legalization pathways, with diverse economic, social and health wellbeing effects. Public health-driven, instead of profit-driven models, seem to offer the most benefits regarding non-medical cannabis legalization. Most of the true public health effects of cannabis legalization are still unknown, for we are still in the early stages of these policies and their implications. Future studies should address the medium-to-long-term social, economic, and health consequences of legalization policies.

Patterns of Cannabis Use among Canadian Youth over Time; Examining Changes in Mode and Frequency Using Latent Transition Analysis

Background: Historically substance use literature has focused on smoking as the main mode of cannabis consumption, so there are knowledge gaps surrounding current understanding of edibles and vaping. These alternative modes of cannabis use are already common among Canadian youth; however, little is known about how these cannabis use patterns change over time. Methods: This study examined the mode (smoking, eating/drinking, vaping) and frequency of cannabis use among a large sample of Canadian youth who participated in 2017–2018 and 2018–2019 data collection waves of the COMPASS study. Using latent transition analysis, this sample consisting of 18,824 youth in grades 9–12 were categorized into cannabis use classes stratified by sex, and their transition between these classes over the one-year period was examined. Results: Three cannabis use classes were identified (occasional multimode, regular multimode, and smoking) alongside one nonuse class. Among youth who reported cannabis use at baseline, transitioning to a multimode group, and/or increasing frequency of multimode use was likely over the one-year period. Conclusions: These findings may highlight a key leverage point for harm-reduction strategies which aim to prevent cannabis related harms associated with high frequency use.

Systematic review of structural and functional neuroimaging studies of cannabis use in adolescence and emerging adulthood: evidence from 90 studies and 9441 participants.

Cannabis use peaks in adolescence, and adolescents may be more vulnerable to the neural effects of cannabis and cannabis-related harms due to ongoing brain development during this period. In light of ongoing cannabis policy changes, increased availability, reduced perceptions of harm, heightened interest in medicinal applications of cannabis, and drastic increases in cannabis potency, it is essential to establish an understanding of cannabis effects on the developing adolescent brain. This systematic review aims to: (1) synthesize extant literature on functional and structural neural alterations associated with cannabis use during adolescence and emerging adulthood; (2) identify gaps in the literature that critically impede our ability to accurately assess the effect of cannabis on adolescent brain function and development; and (3) provide recommendations for future research to bridge these gaps and elucidate the mechanisms underlying cannabis-related harms in adolescence and emerging adulthood, with the long-term goal of facilitating the development of improved prevention, early intervention, and treatment approaches targeting adolescent cannabis users (CU). Based on a systematic search of Medline and PsycInfo and other non-systematic sources, we identified 90 studies including 9441 adolescents and emerging adults (n = 3924 CU, n = 5517 non-CU), which provide preliminary evidence for functional and structural alterations in frontoparietal, frontolimbic, frontostriatal, and cerebellar regions among adolescent cannabis users. Larger, more rigorous studies are essential to reconcile divergent results, assess potential moderators of cannabis effects on the developing brain, disentangle risk factors for use from consequences of exposure, and elucidate the extent to which cannabis effects are reversible with abstinence. Guidelines for conducting this work are provided.

More harm than good? Cannabis, harm and the misuse of drugs act

Purpose This paper aims to consider the nature of cannabis-related harms under the UK’s Misuse of Drugs Act (MDA). Written for the specific context of this four-paper special section on 50 years of the MDA, it argues that the MDA may cause more harm than it prevents. Design/methodology/approach An opinion piece offering a structured overview of cannabis-related harms under prohibition. It summarises existing evidence of the ways in which prohibition may exacerbate existing – and create new – harms related to the production, distribution, use and control of cannabis. Findings The paper argues that prohibition of cannabis under the MDA may cause more harm than it prevents. Originality/value It has long been argued that the MDA does not accurately or fairly reflect the harms of the substances it prohibits, and much existing research points to different ways in which drug prohibition can itself be harmful. The originality of this paper lies in bringing together these arguments and developing a framework for analysing the contribution of prohibition to drug-related harm.