Potential harms from legalization of recreational cannabis use in Canada

Feasibility of a Randomized, Interventional Pilot Clinical Study of Oral Cannabinoids in People with HIV on Antiretroviral Therapy: CTNPT 028

Cannabis-based medicines (CBMs) could help reduce systemic inflammation in people with HIV (PWH). In a prospective, randomized pilot study we enrolled participants from August 2021-April 2022 with HIV, aged ≥18 and on antiretroviral therapy and randomly assigned them to cannabidiol (CBD) ± Δ9-tetrahydrocannabinol (THC) capsules for 12 weeks with the primary objective being to assess safety and tolerability. Here we report on timeliness to study initiation, enrolment, compliance and retention rates. The target sample size was not reached. Two hundred and five individuals were approached, and 10 consented and were randomized; the rest refused (reasons: cannabis-related stigma/discomfort; too many study visits/insufficient time; unwillingness to undergo a "washout period" for three weeks) or were not eligible. The age of those randomized was 58 years (IQR 55-62); 80% were male. Only three met all criteria (30% enrolment compliance); seven were enrolled with minor protocol deviations. Compliance was excellent (100%). Eight (80%) participants completed the study; two (20%) were withdrawn for safety reasons (transaminitis and aggravation of pre-existing anemia). Time to study initiation and recruitment were the most challenging aspects. Ongoing work is required to reduce stigma related to CBMs. Future studies should find a balance between the requirements for safety monitoring and frequency of study visits.

Examining the impact of legalization on the prevalence of driving after using cannabis: A comparison of rural and non-rural parts of Canada

OBJECTIVE

The purpose of this study was to examine the likelihood of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in rural areas and non-rural areas before and after legalization.

METHODS

A multi-wave analysis of Canada's National Cannabis Survey was conducted using logistic regression with interactions to predict the prevalence of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in relation to place of residence (rural or non-rural) and in the weeks and months before and after legalization. Three time points were compared: pre-legalization, two months following legalization and 1 year after legalization.

RESULTS

At the national level, there are no significant differences between the predicted estimates of driving after using cannabis for those who live in rural and non-rural areas. However, when examining the impact of legalization, we found a significant increase in driving after using cannabis among rural residents directly following legalization. Furthermore, it was observed that this increase in driving after using cannabis returns to pre-legalization rates one year after legalization. By contrast, in the weeks and months following legalization, driving after using cannabis decreased among those living in non-rural areas, and slowly increased soon thereafter. No significant differences were observed, in either time period or group, in the prevalence of being a passenger with someone who is driving after using cannabis.

CONCLUSIONS

The finding of significantly higher risk of driving after use of cannabis soon after legalization in rural areas suggests a need for more attention to address immediate concerns for public safety. The increased potential for traffic injuries and deaths in other jurisdictions contemplating legalization supports the call for more and better targeted prevention efforts in rural communities that have far too often been overlooked and under-served.

Cannabis Use Among Adults in Cigarette Smoking Cessation Treatment in Ontario, Canada: Prevalence and Association With Tobacco Cessation Outcome, 2015-2021

Objectives. To examine cannabis use prevalence and its association with tobacco cessation among adults enrolled in cigarette smoking cessation treatment before and after Canada legalized recreational cannabis in October 2018. Methods. The sample comprised 83 206 adults enrolled in primary care-based cigarette smoking cessation treatment between 2015 and 2021 in Ontario, Canada. Past-30-day cannabis use was self-reported at enrollment and cigarette smoking abstinence at 6-month follow-up. Results. Past-30-day prevalence of cannabis use increased from 20.2% in 2015 to 37.7% in 2021. The prevalence increased linearly both before and after legalization. Cannabis and tobacco co-use was associated with lower odds of self-reported cigarette smoking abstinence at 6-month follow-up than tobacco use only (24.4% vs 29.3%; odds ratio [OR] = 0.78; 95% confidence interval [CI] = 0.75, 0.81). This association was attenuated after adjustment for covariates (OR = 0.93; 95% CI = 0.89, 0.97) and weakened slightly over time. Conclusions. Cannabis use prevalence almost doubled from 2015 to 2021 among primary care patients in Ontario seeking treatment to quit cigarettes and was associated with poorer quit outcomes. Further research into the impact of cannabis policy on cannabis and tobacco co-use is warranted to mitigate harm. (Am J Public Health. 2024;114(1):98-107. https://doi.org/10.2105/AJPH.2023.307445).

The development of a Cannabis Knowledge Assessment Tool (CKAT)

BACKGROUND

Misconceptions about the health risks of cannabis remain prevalent, indicating the need to improve public health messaging and determine the effectiveness of educational programming. Our objective was to develop a standardized questionnaire to measure knowledge about cannabis in the context of cannabis legalization.

METHODS

A Cannabis Knowledge Assessment Tool (CKAT) was created using the Delphi method. A purposive sample of healthcare professionals, policymakers, academics, patients, and students served as the content and development experts. Principal component analysis from the codes identified from open-ended feedback guided the item development. Upon completion, the CKAT was administered as a pre- and post-test in four schools (7th and 9th Grade) in Canada. The data were analysed to determine whether knowledge scores changed after participating in a cannabis education program.

RESULTS

Twenty-four experts initially participated in the Delphi process and 18 (75% retention) continued throughout. Principal component analysis identified 3 domains: 1) effects of cannabis on the individual, 2) general information about cannabis, and 3) cannabis harm reduction. The final questionnaire consisted of 16 multiple-true-false questions (64 items) and received a Flesch-Kincaid Grade Level of 6.3, and a SMOG index score of 7.6. The CKAT was completed by 132 students; seventy-three 7th grade and fifty-nine 9th grade students. The baseline mean CKAT score was 46.2 (SD:5.5), which increased to 50.7 (SD:4.6) after the cannabis educational program (p<0.05).

CONCLUSIONS

A novel tool to measure knowledge of cannabis was developed and piloted in 7th grade and 9th grade students. Future studies are required to test usability and validity of the CKAT in other contexts.

Changes in Quantity Measures of Various Forms of Cannabis Consumption among Emerging Adults in Canada in Relation to Policy and Public Health Developments

Limited research examines changes in quantities of various forms of smoked/vaped cannabis among regular consumers, including emerging adults (EAs; 18 to 29) in Canada. This information is particularly relevant in the current context of emerging cannabis behaviors among EAs related to political amendments (legalization of cannabis), vaping-related lung illnesses (EVALI), and unprecedented pandemics (COVID-19). This study investigated the impact of legalizing recreational cannabis use in Canada, the EVALI epidemic, and the COVID-19 pandemic on the quantity of smoked/vaped forms of cannabis in relation to gender differences. EAs retrospectively self-reported the quantity of herb, hash, concentrates, joint size, and the number of joints and vaping cartridges in relation to three consecutive developments: pre-legalization, post-legalization; pre-EVALI, post-EVALI, pre-COVID-19, and during COVID-19. The quantity of herb use significantly increased among heavy users, and vaping quantity significantly increased among light users. Overall, an increasing incremental trend was observed in the average quantity of cannabis forms used over time. Males consumed higher quantities of all cannabis forms than females. More males than females reported using concentrates (p < 0.05). These findings reveal unique aspects of the amount of various cannabis forms smoked/vaped in relation to gender and provides preliminary evidence of cannabis consumption behaviors in relation to changing social and cultural contexts.

Predictors of perceived symptom change with acute cannabis use for mental health conditions in a naturalistic sample: A machine learning approach

BACKGROUND

Despite limited clinical evidence of its efficacy, cannabis use has been commonly reported for the management of various mental health concerns in naturalistic field studies. The aim of the current study was to use machine learning methods to investigate predictors of perceived symptom change across various mental health symptoms with acute cannabis use in a large naturalistic sample.

METHODS

Data from 68,819 unique observations of cannabis use from 1307 individuals using cannabis to manage mental health symptoms were analyzed. Data were extracted from Strainprint®, a mobile app that allows users to monitor their cannabis use for therapeutic purposes. Machine learning models were employed to predict self-perceived symptom change after cannabis use, and SHapley Additive exPlanations (SHAP) value plots were used to assess feature importance of individual predictors in the model. Interaction effects of symptom severity pre-scores of anxiety, depression, insomnia, and gender were also examined.

RESULTS

The factors that were most strongly associated with perceived symptom change following acute cannabis use were pre-symptom severity, age, gender, and the ratio of CBD to THC. Further examination on the impact of baseline severity for the most commonly reported symptoms revealed distinct responses, with cannabis being reported to more likely benefit individuals with lower pre-symptom severity for depression, and higher pre-symptom severity for insomnia. Responses to cannabis use also differed between genders.

CONCLUSIONS

Findings from this study highlight the importance of several factors in predicting perceived symptom change with acute cannabis use for mental health symptom management. Mental health profiles and baseline symptom severity may play a large role in perceived responses to cannabis. Distinct response patterns were also noted across commonly reported mental health symptoms, emphasizing the need for placebo-controlled cannabis trials for specific user profiles.

Safety and Tolerability of Oral Cannabinoids in People Living with HIV on Long-Term ART: A Randomized, Open-Label, Interventional Pilot Clinical Trial (CTNPT 028)

BACKGROUND

With anti-inflammatory properties, cannabinoids may be a potential strategy to reduce immune activation in people living with HIV (PLWH) but more information on their safety and tolerability is needed.

METHODS

We conducted an open-label interventional pilot study at the McGill University Health Centre in Montreal, Canada. PLWH were randomized to oral Δ9-tetrahydrocannabinol (THC): cannabidiol (CBD) combination (THC 2.5 mg/CBD 2.5 mg) or CBD-only capsules (CBD 200 mg). Individuals titrated doses as tolerated to a maximum daily dose THC 15 mg/CBD 15 mg or 800 mg CBD, respectively, for 12 weeks. The primary outcome was the percentage of participants without any significant toxicity based on the WHO toxicity scale (Grades 0-2 scores).

RESULTS

Out of ten individuals, eight completed the study. Two from the CBD-only arm were withdrawn for safety concerns: phlebotomy aggravating pre-existing anemia and severe hepatitis on 800 mg CBD with newly discovered pancreatic adenocarcinoma, respectively. Seven did not have any significant toxicity. Cannabinoids did not alter hematology/biochemistry profiles. CD4 count, CD4/CD8 ratio, and HIV suppression remained stable. Most adverse effects were mild-moderate.

CONCLUSIONS

In PLWH, cannabinoids seem generally safe and well-tolerated, though larger studies are needed. Screening for occult liver pathology should be performed and hepatic enzymes monitored, especially with high CBD doses.

Between Science and Big Business: Tapping Mary Jane's Uncharted Potential

At the intersection of science and medicine, government policy, and pop culture, cannabis has prompted society since the beginning of recorded history. And yet, there is comparatively little replicable data on the plant, its constituents, and their capacity to modify human physiology. Over the past decades, several findings have pointed toward the importance of the endogenous cannabinoid system in maintaining homeostasis, making it an important target for various diseases. Here, we summarize the current state of knowledge on endogenous- and plant-based cannabinoids, address the issues related to cannabinoid-based drug discovery, and incite efforts to utilize their polypharmacological profile toward tackling diseases with a complex underlying pathophysiology. By fusing modern science and technology with the empirical data that has been gathered over centuries, we propose an outlook that could help us overcome the dearth of innovation for new drugs and synchronously redefine the future of drug discovery. Simultaneously, we call attention to the startling disconnect between the scientific, regulatory, and corporate entities that is becoming increasingly evident in this booming industry.

3-Year Follow-up of Lower Risk Cannabis Use Patterns: Evidence from a Longitudinal Survey

OBJECTIVES

Following recommendations from the Lower Risk Cannabis Use Guidelines, we evaluated how lower risk cannabis use (late initiation and low use frequency) was associated with the risk of developing cannabis abuse/dependence over a 3-year follow-up period compared to 12-month abstinence (controls) or higher risk cannabis use (early initiation and higher use frequency). We also explored the effect of cannabis quantity.

METHODS

Data were obtained from the U.S. nationally representative survey, National Epidemiologic Survey on Alcohol and Related Conditions wave I (2001 to 2002) and wave II (2004 to 2005), which included 31,464 respondents with no lifetime history of cannabis abuse/dependence at the first interview. We applied multiple logistic regression and propensity score matching analyses to examine the association between different use patterns at wave I and cannabis abuse/dependence at wave II, adjusting for covariates. Lower risk cannabis use and the transition to higher use frequency were also assessed.

RESULTS

For propensity score analysis, lower risk cannabis use at wave I was associated with higher risk of cannabis use/dependence at wave II compared to controls (odds ratio [OR]: 4.27; 95% confidence interval [95% CI], 1.57 to 11.61); however, there was no association with use frequency increase (OR: 2.52; 95% CI, 0.88 to 7.17). Higher risk use had a greater risk of cannabis use/dependence than controls (OR: 6.27; 95% CI, 2.56 to 15.38) and lower risk use (OR: 2.69; 95% CI, 1.12 to 6.47). Logistic regression analyses showed similar results, except that lower risk use was significantly associated with use frequency increase (OR: 2.49; 95% CI, 1.22 to 5.08). For the lower risk use group, 1 to 3 joints/day of use was significantly associated with cannabis abuse/dependence.

CONCLUSIONS

We found that following recommended use patterns can significantly lower one's risk of cannabis abuse/dependence. However, risk of cannabis abuse/dependence is still 4 times higher than staying abstinent. Updated recommendations on safe cannabis exposure levels are needed to guide cannabis use in the general population after cannabis legalization.

Changes in California cannabis exposures following recreational legalization and the COVID-19 pandemic

INTRODUCTION

Since 2012, eighteen states and the District of Columbia have legalized recreational cannabis. Past research suggests this policy change is associated with increased cannabis exposures however this has not yet been studied in California, despite its status as the world's largest legal cannabis market.

METHODS

This observational, retrospective study analyzed trends in cannabis exposures reported to the California Poison Control System (CPCS) from 2010 to 2020. We assessed shifts in exposures before and after the legalization of recreational cannabis in November 2016, the establishment of recreational retail sales in January 2018, and the institution of a statewide shelter-in-place order due to the COVID-19 pandemic in March 2020 using interrupted time-series analysis and reviewed all records to identify specific products associated with exposures.

RESULTS

Between 2010 and 2020 edible exposures increased from near zero to 79% of exposures in 2020. Cannabis exposures significantly increased following recreational legalization in 2016 (by an estimated 2.07 exposures per month [CI: 0.60, 3.55]; p < 0.01) and initiation of retail sales in 2018 (0.85 [CI: 0.12, 1.58]; p < 0.05). There was no significant change in cannabis exposures following the first shelter-in-place order of the COVID-19 pandemic (1.59 [CI: -1.61, 3.68]; p = 0.43). Cannabis exposures for those thirteen and under increased significantly both after recreational legalization (1.04 [CI: 0.38, 1.70]) and after the opening of the retail sales market (0.73 [CI: 0.34, 1.12]), but not following the shelter-in-place order (1.59 [CI: -1.61, 3.68]), nor was there a significant change for those older than thirteen.

CONCLUSIONS

Our findings suggest that cannabis legalization is linked to increased exposures, particularly for products such as gummies and candy edibles among children under the age of thirteen. Clinicians should be aware of these risks and communicate them to patients, and policymakers should consider stronger regulations on packaging to reduce these exposures.Key pointsQuestion: How have cannabis exposures changed following legalization of recreational use, the opening of the recreational retail sales market, and the institution of shelter-in-place orders during the COVID-19 pandemic?Findings: In this retrospective review of 10,757 cases reported to the California Poison Control System (CPCS) between 2010 and 2020, exposures increased significantly after the legalization of recreational cannabis use and the opening of the recreational retail sales market, particularly among children, who primarily consumed candies and gummies.Meaning: Stronger regulation of cannabis edibles that mimic other products is warranted to decrease exposures among children.

Cannabis and Lung Health: Does the Bad Outweigh the Good?

Cannabis use is growing, with multiple medical ‘indications’ and approval for recreational use in many countries. This article will review some of the respiratory complications to cannabis use, which include lung function changes, lung destruction, increased risk of lung and head and neck cancer, and others. These are mostly related to smoking, and the co-administration of nicotine makes the risks a bit difficult to measure. However, with many reports of EVALI, electronic vaping-associated lung injury, being related to cannabis coadministration, it appears that the safest administration of cannabis, as far as lung health, is orally.

High-intensity cannabis use and hospitalization: a prospective cohort study of street-involved youth in Vancouver, Canada

BACKGROUND

There is concern that cannabis use negatively affects vulnerable groups such as youth; however, the relationship between cannabis use and health care utilization has not been well characterized in this population. We longitudinally evaluated the association between daily cannabis use and hospitalization among a prospective cohort of street-involved youth.

METHODS

Data were collected from the At-Risk Youth Study (ARYS) in Vancouver, Canada, from September 2005 to May 2015. Participants were interviewed semi-annually and multivariable generalized estimating equation (GEE) logistic regression was used to examine the relationship between daily cannabis use and hospitalization.

RESULTS

A total of 1216 participants (31.2% female) were included in this analysis, and 373 (30.7%) individuals reported hospitalization at some point during the study period. In a multivariable GEE analysis, daily cannabis use was not significantly associated with hospitalization (Adjusted Odds Ratio [AOR] = 1.17, 95% Confidence interval [CI] = 0.84, 1.65). We did observe a significant interaction between daily cannabis use and sex (AOR = 0.51, 95% CI = 0.34, 0.77), whereby cannabis use was associated with a decreased odds of hospitalization among males (AOR = 0.60, 95% CI = 0.47, 0.78), yet was not significantly associated with hospitalization among females (AOR = 1.19, 95% CI = 0.84, 1.67).

CONCLUSIONS

The finding that daily cannabis use was not associated with hospitalization among street-involved youth is encouraging given the high rates of cannabis use in this population and the expansion of cannabis legalization and regulation. Future studies, however, are warranted to monitor possible changes in the consequences of cannabis use as cannabis legalization and regulation increase internationally.

Down and High: Reflections Regarding Depression and Cannabis

In light of the recent changes in the legal status of cannabis in Canada, the understanding of the potential impact of the use of cannabis by individuals suffering from depression is increasingly considered as being important. It is fundamental that we look into the existing literature to examine the influence of cannabis on psychiatric conditions, including mood disorders. In this article, we will explore the relationship that exists between depression and cannabis. We will examine the impact of cannabis on the onset and course of depression, and its treatment. We have undertaken a wide-ranging review of the literature in order to address these questions. The evidence from longitudinal studies suggest that there is a bidirectional relationship between cannabis use and depression, such that cannabis use increases the risk for depression and vice-versa. This risk is possibly higher in heavy users having initiated their consumption in early adolescence. Clinical evidence also suggests that cannabis use is associated with a worse prognosis in individuals with major depressive disorder. The link with suicide remains controversial. Moreover, there is insufficient data to determine the impact of cannabis use on cognition in individuals with major depression disorder. Preliminary evidence suggesting that the endogenous cannabinoid system is involved in the pathophysiology of depression. This will need to be confirmed in future positron emission tomography studies. Randomized controlled trials are needed to investigate the potential efficacy of motivational interviewing and/or cognitive behavioral therapy for the treatment of cannabis use disorder in individuals with major depressive major disorder. Finally, although there is preclinical evidence suggesting that cannabidiol has antidepressant properties, randomized controlled trials will need to properly investigate this possibility in humans.

Young and under the influence: A systematic literature review of the impact of cannabis on the driving performance of youth

BACKGROUND

Young drivers ages 15-24 continue to constitute a high-risk population for fatal motor vehicle collisions (MVCs) compared to all other age groups. Driving under the influence of cannabis is an important contributor to the high rates of MVCs among youth. Understanding the specific impact of cannabis on the driving performance outcomes of young drivers can inform injury prevention, education, and intervention strategies.

OBJECTIVES

This systematic literature review (SLR) aims to determine the Class (I- highest to IV-lowest) of evidence and level of confidence (A-high to U-insufficient) in the effects of cannabis on the driving performance of young drivers.

METHODS

Registered in PROSPERO (#CRD42020180541), this SLR searched seven data bases and appraised the quality and confidence in the evidence using an established research methodology.

RESULTS

Class II evidence suggests that THC is likely to reduce mean speed, headway distance, and reaction time; and increase lane and steering wheel position variability among young drivers (Level B, moderate confidence).

CONCLUSIONS

This study shows that there is a moderate to low level of confidence on the impact of cannabis on the specific driving performance outcomes of young drivers. A need remains for Class I and II studies that focus on the specific effects on young drivers, distinguish between the biological and socially constructed variables of sex and gender, and includes larger and more representative samples.

Legalization of cannabis use in Canada: Impacts on the cannabis use profiles of youth seeking services for substance use

BACKGROUND

Cannabis is a highly used substance among youth, but has the potential to negatively impact the developing brain. Recreational cannabis use was legalized in Canada in October 2018. This exploratory study examines cannabis use profiles of high-risk youth before and after the national legalization of recreational cannabis use.

METHOD

This cross-sectional cohort study examines the cannabis use profiles of two cohorts of youth, one recruited prior to legalization (N = 101) and one recruited after legalization (N = 168).

RESULTS

This study found few changes in cannabis use patterns after legalization. The rate of high-frequency cannabis use, polysubstance use, social circles of use, and mental health and substance use challenges showed no change, and the study found no associations with age. Exceptions were that youth were more likely to report purchasing cannabis from a legal source after legalization. Concealment of cannabis use from legal authorities declined after legalization among youth over the age of majority (19+ years), but not among younger youth (<19 years).

CONCLUSIONS

Minimal changes have occurred in the cannabis use patterns of service-seeking youth in the short term following legalization. This holds true both for youth who have reached the age of majority and those who have not. Nevertheless, this population has overlapping substantial mental health and substance use challenges. Integrated services should address cannabis use and other concurrent challenges and be sensitive to the postlegalization social climate.

Upconverting nanoparticle clustering based rapid quantitative detection of tetrahydrocannabinol (THC) on lateral-flow immunoassay

Cannabis, also known as marijuana, is the most abused psychoactive drug worldwide.

Driving-Related Behaviours, Attitudes and Perceptions among Australian Medical Cannabis Users: Results from the CAMS 18-19 Survey

As the use of cannabis for medical purposes becomes increasingly prevalent, driving under the influence of cannabis (DUIC) is emerging as a major public health issue. Understanding current behaviours, attitudes and perceptions around DUIC in medical cannabis users is an important first step in addressing this issue. Here we present the results from the driving-related subsection of the Cannabis as Medicine 2018-2019 Survey (CAMS18) of current Australian medical cannabis users (n = 1388). Of the 806 respondents who reported driving a motor vehicle in the last month, 34.6% said they typically drive within 3 hours of cannabis use, thereby risking DUIC, while more than 50% waited at least 7 hours before driving. A majority of respondents thought that their medical cannabis use did not affect their driving ability, and most denied any specific effects of cannabis on speeding, risk taking, reaction time, attentiveness or lane departures. A substantial majority (70.9%) felt confident in accurately assessing their own driving ability after using medical cannabis. Binary logistic regression showed that frequency of use and confidence to assess driving ability were strongly related to DUIC behaviour (i.e. driving soon after cannabis use). These results suggest a relatively high prevalence of DUIC and low perception of risk among this sample of medical cannabis users. Further research is needed to better understand the acute and chronic effects of medical cannabis use on driving and the relation between perceived and actual driving ability.

Frequent Cannabis Use Is Negatively Associated with Frequency of Injection Drug Use Among People Who Inject Drugs in a Canadian Setting

Objectives: High levels of morbidity and mortality associated with injection drug use continue to represent a significant public health challenge in many settings worldwide. Previous studies have shown an association between cannabis use and decreased risk of some drug-related harms. We sought to evaluate the association between high-intensity cannabis use and the frequency of injection drug use among people who inject drugs (PWID). Methods: The data for this analysis were collected from three prospective cohorts of PWID in Vancouver, Canada, between September 2005 and May 2018. Generalized linear mixed-effects models were used to analyze the association between daily cannabis use and the frequency of injecting illegal drugs (i.e., self-reported average number of injections per month). Results: Among the 2,619 active PWID, the frequency of injection drug use was significantly lower among people who use cannabis daily compared with people who use it less than daily (adjusted odds ratio [AOR]=0.84, 95% confidence interval [CI]: 0.73-0.95). Sub-analyses indicated that this effect was restricted to the frequency of illegal opioid injection (AOR=0.78, 95% CI: 0.68-0.90); the association between daily cannabis use and the frequency of illegal stimulant injection was not significant (AOR=1.08, 95% CI 0.93-1.25). Discussion: The findings from these prospective cohorts suggest that people who use cannabis daily were less likely to report daily injection of illegal drugs compared with people who use it less than daily. These results suggest the potential value of conducting experimental research to test whether controlled administration of cannabinoids impacts the frequency of illegal opioid injection among PWID.

Frequent Cannabis Use and Cessation of Injection of Opioids, Vancouver, Canada, 2005-2018

Objectives. To evaluate the impact of frequent cannabis use on injection cessation and injection relapse among people who inject drugs (PWID).Methods. Three prospective cohorts of PWID from Vancouver, Canada, provided the data for these analyses. We used extended Cox regression analysis with time-updated covariates to analyze the association between cannabis use and injection cessation and injection relapse.Results. Between 2005 and 2018, at-least-daily cannabis use was associated with swifter rates of injection cessation (adjusted hazard ratio [AHR] = 1.16; 95% confidence interval [CI] = 1.03, 1.30). A subanalysis revealed that this association was only significant for opioid injection cessation (AHR = 1.26; 95% CI = 1.12, 1.41). At-least-daily cannabis use was not significantly associated with injection relapse (AHR = 1.08; 95% CI = 0.95, 1.23).Conclusions. We observed that at-least-daily cannabis use was associated with a 16% increase in the hazard rate of injection cessation, and this effect was restricted to the cessation of injection opioids. This finding is encouraging given the uncertainty surrounding the impact of cannabis policies on PWID during the ongoing opioid overdose crisis in many settings in the United States and Canada.

Facing the option for the legalisation of cannabis use and supply in New Zealand: An overview of relevant evidence, concepts and considerations

ISSUES

Non-medical cannabis policies are changing, including towards legalisation-with-regulation frameworks. New Zealand will hold a public referendum on cannabis legalisation in 2020. We reviewed data on cannabis use and health/social harms; policy reform options; experiences with and outcomes of reforms elsewhere; and other relevant considerations towards informing policy choices in the upcoming referendum.

APPROACH

Relevant epidemiological, health, social, criminal justice and policy studies and data were identified and comprehensively reviewed.

KEY FINDINGS

Cannabis use is common (including in New Zealand) and associated with risks for health and social harms, mainly concentrated in young users; key harms are attributable to criminalisation. 'Decriminalisation' reforms have produced ambivalent results. Existing cannabis legalisation frameworks vary considerably in main parameters. Legalisation offers some distinct advantages, for example regulated use, products and user education, yet outcomes depend on essential regulation parameters, including commercialisation, and policy ecologies. While major changes in use are not observed, legalisation experiences are inconclusive to date, including mixed health and social outcomes, with select harms increasing and resilient illegal markets. It is unclear whether legalisation reduces cannabis exposure or social harms (e.g. from enforcement) for youth.

IMPLICATIONS/CONCLUSIONS

No conclusive overall evidence on the outcomes of legalisation elsewhere exists, nor is evidence easily transferable to other settings. Legalisation offers direct social justice benefits for adults, yet overall public health impacts are uncertain. Legalisation may not categorically improve health or social outcomes for youth. Legalisation remains a well-intended, while experimental policy option towards more measured and sensible cannabis control and overall greater policy coherence, requiring close monitoring and possible adjustments depending on setting-specific outcomes.

Assessing the public health impacts of legalizing recreational cannabis use: the US experience

The sale of cannabis for adult recreational use has been made legal in nine US states since 2012, and nationally in Uruguay in 2013 and Canada in 2018. We review US research on the effects of legalization on cannabis use among adults and adolescents and on cannabis-related harms; the impact of legalizing adult recreational use on cannabis price, availability, potency and use; and regulatory policies that may increase or limit adverse effects of legalization. The legalization of recreational cannabis use in the US has substantially reduced the price of cannabis, increased its potency, and made cannabis more available to adult users. It appears to have increased the frequency of cannabis use among adults, but not so far among youth. It has also increased emergency department attendances and hospitalizations for some cannabis-related harms. The relatively modest effects on cannabis use to date probably reflect restrictions on the number and locations of retail cannabis outlets and the constraints on commercialization under a continued federal prohibition of cannabis. Future evaluations of legalization should monitor: cannabis sales volumes, prices and content of tetrahydrocannabinol; prevalence and frequency of cannabis use among adolescents and adults in household and high school surveys; car crash fatalities and injuries involving drivers who are cannabis-impaired; emergency department presentations related to cannabis; the demand for treatment of cannabis use disorders; and the prevalence of regular cannabis use among vulnerable young people in mental health services, schools and the criminal justice system. Governments that propose to legalize and regulate cannabis use need to fund research to monitor the impacts of these policy changes on public health, and take advantage of this research to develop ways of regulating can-nabis use that minimize adverse effects on public health.

Recreational Cannabis Legalization in the US and Maternal Use during the Preconception, Prenatal, and Postpartum Periods

In the United States (US), recreational cannabis use is on the rise. Since 2011, 11 states and the District of Columbia have legalized cannabis for adult recreational use. As additional states consider legalizing, there is an urgent need to assess associations between recreational cannabis legalization and maternal use in the preconception, prenatal, and postpartum periods—all critical windows for maternal and child health. Using cross-sectional data from the 2016 Pregnancy Risk Assessment Monitoring System, we assessed associations between state cannabis legalization and self-reported maternal cannabis use. Using logistic regression, we estimated the adjusted prevalence ratio (PR) of cannabis use during the preconception, prenatal, and postpartum period for women delivering a live-born infant in three states that had legalized recreational cannabis (Alaska, Colorado, and Washington) and three states that had not legalized (Maine, Michigan, and New Hampshire) by 2016. Our final sample size was 7258 women. We utilized 95% confidence intervals (CI) and a significance level of alpha = 0.05. After adjustment for potential confounders, women who resided in states with legalized recreational cannabis were significantly more likely to use cannabis during the preconception (PR 1.52; 95%CI ranging from 1.28–1.80; p < 0.001), prenatal (PR 2.21; 95% CI ranging from 1.67–2.94; p < 0.001), and postpartum (PR 1.73; 95%CI ranging from 1.30–2.30; p < 0.001) periods, compared to women who resided in states without legalized recreational cannabis. Although evidence about the effect of marijuana use during these periods is nascent, these findings show potential for increased incidence of child exposure to cannabis. Longitudinal research is needed to assess immediate and sustained impacts of maternal use before and after state legalization of recreational cannabis.

Population pharmacokinetic modeling of plasma Δ9-tetrahydrocannabinol and an active and inactive metabolite following controlled smoked cannabis administration

AIMS

Population pharmacokinetic models of Δ9-tetrahydrocannabinol (THC) have been developed for THC plasma and blood concentration data. Often, only the metabolites of THC are measurable when blood samples are obtained. Therefore, we performed a population pharmacokinetic analysis of THC, 11-OH-THC and THCCOOH plasma concentration data from a Phase I clinical trial of THC smoking.

METHODS

Frequently obtained plasma THC, 11-OH-THC and THCCOOH concentration data were obtained over 168 h from 6 subjects who smoked low (15.8 mg) and high dose (33.8 mg) THC cigarettes on 2 occasions. Bayesian estimates of the THC pharmacokinetic model from each individual for each dose were fixed prior to the sequential pharmacokinetic analysis of the metabolites.

RESULTS

A 3-compartment model of THC was developed that has a steady-state volume of distribution (Vd_SS ) of 3401 ± 788 L and a clearance of 0.72 ± 0.10 L/min. 11-OH-THC was characterized by 50 ± 6% of the THC being directly cleared to a 3-compartment model with a Vd_SS of 415.2 ± 4.3 L and clearance of 0.78 ± 0.05 L/min. The THCCOOH model shared the central compartment of the 11-OH-THC model with a Vd_SS of 29.1 ± 0.05 L and a clearance of 0.12 ± 0.02 L/min. First order kinetics were observed for THC and THCCOOH between the low and high doses, but a nonlinear pattern was observed for 11-OH-THC.

CONCLUSION

We describe the pharmacokinetics of THC, 11-OH-THC and THCCOOH including inter- and intraindividual variability of the parameter estimates of the model.

Cannabinoids and inflammation: implications for people living with HIV

: Thanks to the success of modern antiretroviral therapy (ART), people living with HIV (PLWH) have life expectancies which approach that of persons in the general population. However, despite the ability of ART to suppress viral replication, PLWH have high levels of chronic systemic inflammation which drives the development of comorbidities such as cardiovascular disease, diabetes and non-AIDS associated malignancies. Historically, cannabis has played an important role in alleviating many symptoms experienced by persons with advanced HIV infection in the pre-ART era and continues to be used by many PLWH in the ART era, though for different reasons. Δ-Tetrahydrocannabinol (Δ-THC) and cannabidiol (CBD) are the phytocannabinoids, which have received most attention for their medicinal properties. Due to their ability to suppress lymphocyte proliferation and inflammatory cytokine production, there is interest in examining their therapeutic potential as immunomodulators. CB2 receptor activation has been shown in vitro to reduce CD4 T-cell infection by CXCR4-tropic HIV and to reduce HIV replication. Studies involving SIV-infected macaques have shown that Δ-THC can reduce morbidity and mortality and has favourable effects on gut mucosal immunity. Furthermore, ΔTHC administration was associated with reduced lymph node fibrosis and diminished levels of SIV proviral DNA in spleens of rhesus macaques compared with placebo-treated macaques. In humans, cannabis use does not induce a reduction in peripheral CD4 T-cell count or loss of HIV virological control in cross-sectional studies. Rather, cannabis use in ART-treated PLWH was associated with decreased levels of T-cell activation, inflammatory monocytes and pro-inflammatory cytokine secretion, all of which are related to HIV disease progression and comorbidities. Randomized clinical trials should provide further insights into the ability of cannabis and cannabinoid-based medicines to attenuate HIV-associated inflammation. In turn, these findings may provide a novel means to reduce morbidity and mortality in PLWH as adjunctive agents to ART.

Detection of Δ9 THC in oral fluid following vaporized cannabis with varied cannabidiol (CBD) content: An evaluation of two point-of-collection testing devices

Point‐of‐collection testing (POCT) for Δ⁹‐tetrahydrocannabinol (THC) in oral fluid is increasingly used to detect driving under the influence of cannabis (DUIC). However, previous studies have questioned the reliability and accuracy of two commonly used POCT devices, the Securetec DrugWipe^® 5 s (DW5s) and Dräger DrugTest^® 5000 (DT5000). In the current placebo controlled, double‐blind, crossover study we used liquid chromatography‐tandem mass spectrometry (LC–MS/MS) to accurately quantify cannabinoid concentrations in the oral fluid of 14 participants at various timepoints (10, 60, 120, and 180 minutes) following vaporization of 125 mg of THC‐dominant (11% THC; <1% CBD), THC/CBD equivalent (11% THC; 11% CBD) and placebo (<1% THC; <1% CBD) cannabis. At each timepoint, oral fluid was also screened using the DW5s (10 ng/mL THC cut‐off) and DT5000 (10 ng/mL THC cut‐off). LC–MS/MS analysis showed peak oral fluid THC concentrations at the 10 minute timepoint with a rapid decline thereafter. This trajectory did not differ with THC dominant and THC/CBD equivalent cannabis. With a 10 ng/mL confirmatory cut‐off, 5% of DW5s test results were false positives and 16% false negatives. For the DT5000, 10% of test results were false positives and 9% false negatives. Neither the DW5s nor the DT5000 demonstrated the recommended >80% sensitivity, specificity and accuracy. Accuracy was lowest at 60 minutes, when THC concentrations were often close to the screening cut‐off (10 ng/mL). POCT devices can be useful tools in detecting recent cannabis use; however, limitations should be noted, and confirmatory LC–MS/MS quantification of results is strongly advisable.