Article

Who consumes most of the cannabis in Canada? Profiles of cannabis consumption by quantity

September 2019
Drug and Alcohol Dependence 205:107587

DOI:10.1016/j.drugalcdep.2019.107587

Authors:

Russell C Callaghan

University of Northern British Columbia

Marcos Rogerio Sanches

Centre for Addiction and Mental Health

Claire Benny

University of Alberta

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Aim: To establish whether the population-level pattern of cannabis use by quantity is similar to the distributions previously reported for alcohol, in which a small subset of drinkers accounts for a majority of total population alcohol consumption. Method: The current study pooled Waves 1-3 of the 2018 National Cannabis Survey (n = 18,900; 2584 past-three-month cannabis users), a set of stratified, population-based surveys designed to assess cannabis consumption and related behaviors in Canada. Each survey systematically measured self-reported cannabis consumption by quantity across seven of the major cannabis-product types. In order to enable the conversion of self-reported consumption of non-flower cannabis products into a standard joint equivalent (SJE: equal to 0.5 g of dried cannabis), we created conversion metrics for physical production equivalencies across cannabis products. Results: Similar to the findings in the alcohol literature, study results show that cannabis consumption is highly concentrated in a small subset of users: the upper 10% of cannabis users accounted for approximately two-thirds of all cannabis consumed in the country. Males reported consuming more cannabis by volume than females (approximately 60% versus 40%), with young males (15-34 years old) being disproportionately represented in the heaviest-using subgroups. Conclusions: Most of the cannabis used in Canada is consumed by a relatively small population of very heavy cannabis users. Future research should attempt to identify the characteristics of the heaviest-using groups, as well as how population-level cannabis consumption patterns relate to the calculus of cannabis-related harms in society.

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

Article

Full-text available

Jun 2023
Int J Environ Res Publ Health

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.

Measuring cannabis quantities in online surveys: A rapid review and proposals for ways forward

Article

Full-text available

Apr 2023

Objectives Cannabis use quantities are relevant for determining cannabis‐related harms. This research aims to provide an overview of the available methods to assess quantities through self‐report. Methods A rapid review of various strategies to collect information on cannabis use quantities through self‐report. Two independent literature searches resulted in n = 38 studies included for review. Results A total of n = 14 studies employed methods for collecting cannabis use quantities that are not suitable for online surveys (e.g., rolling a fake joint). Of the remaining n = 24 studies with items that are suitable for online surveys, the quantity assessment was performed in three different ways. The data collection was either carried out by asking (a) for the total number of joints (i.e., crude joint method), (b) for the total weight (i.e., crude weight method), or (c) for specific products separately, for example, for the amount of flower and resin (i.e., product‐specific method). In only n = 8 studies, cannabis use quantities were ascertained by providing visual aids (e.g., illustration of various amounts of flower). Conclusions The crude joint method and the product‐specific method are the two most promising methods to collect information on cannabis use quantities. Using visual aids may potentially improve the accuracy of those methods.

Concurrent validity of the Marijuana Purchase Task: A meta‐analysis of trait‐level cannabis demand and cannabis involvement

Article

Full-text available

Oct 2022

Background and aims: The Marijuana Purchase Task (MPT) is increasingly used to measure cannabis reinforcing value and has potential utility 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= 4,077, median % females: 44.8%: weighted average age= 29.08 (SD: 6.82)], published between 2015-2022. Intensity, Omax and elasticity showed the most robust concurrent validity [|r's|= .147-325, ps <.014] with the largest significant effect sizes for quantity [|r| intensity= .325] and cannabis dependence [|r|Omax = .320,|r|intensity= .305,|r|elasticity= .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 appears to have concurrent validity to quantify cannabis demand, most robustly for intensity, Omax and elasticity. Moderating effects by sex suggest potentially meaningful sex differences in the reinforcing value of cannabis.

Trends in the use of cannabis products in Canada and the USA, 2018 – 2020: Findings from the International Cannabis Policy Study

Article

Jul 2022
INT J DRUG POLICY

Background and Aims There is little information on consumption patterns across the diverse range of cannabis product types. This paper examines trends in consumption patterns in Canada and the United States (US) between 2018-2020. Design Repeat cross-sectional surveys were conducted as part of the International Cannabis Policy Study online survey in 2018 (n=27,024), 2019 (n=45,426), and 2020 (n=45,180). Setting Respondents were recruited from commercial panels in Canada and US states that had and had not legalized non-medical cannabis (US ‘legal’ and ‘illegal’ states, respectively). Participants Respondents were male and female participants aged 16-65 years. Measurements Data on frequency and consumption amounts were collected for nine types of cannabis products, including dried flower and processed products (e.g., oils and concentrates). Consumers were also asked about mixing cannabis with tobacco. Socio-demographic information was collected. Findings Dried flower was the most commonly used product, although use in the past 12 months declined between 2018 and 2020 in Canada (81% to 73%), US legal (78% to 72%) and illegal states (81% to 76%; p<0.05 for all). Prevalence of past 12-month use increased for virtually all other product forms, although prevalence of daily use remained stable across years. In 2020, edibles and vape oils were the most commonly used products after flower. Use of non-flower products was highest in US legal states, although similar trends were observed in all jurisdictions. Males were more likely to report using processed products, and vape oils were the most commonly processed product among 16-20-year-olds. Daily use of cannabis flower increased in US legal and illegal states, and average joint size increased across all jurisdictions over time. Conclusions Dried flower remains the dominant product in Canada and the US; however, use of processed cannabis products has increased, with the largest increases observed in legal cannabis markets.

Primary crime-related outcome indicators associated with recreational cannabis legalization: a comprehensive literature and data review

Article

Full-text available

Jul 2024
CRIME LAW SOCIAL CH

Cannabis policies are increasingly being liberalized, including the implementation of formal legalization policies of non-medical use and supply in multiple jurisdictions (initially in the Americas) towards improved public health and safety objectives. While focus on health indicators has shown mixed or adverse outcomes, less attention has been given to social-legal – and specifically crime-related – outcomes of legalization. We conducted a comprehensive literature and data review of key crime-related outcomes associated with non-medical cannabis legalization in four main domains, based on targeted searches of recent academic (e.g., journal publication) and ‘grey’ English-language literature sources: 1) cannabis-related crimes and enforcement, and other crimes; 2) cannabis-impaired driving and related motor-vehicle-crashes; 3) cannabis sourcing by consumers; and 4) cannabis market evolution and dynamics. The data identified were extracted, organized and narratively summarized by topic. The data reviewed suggest that cannabis-related crimes and enforcement have substantially decreased, yet arbitrary (e.g., racialized) enforcement patterns – involving both adults and youths – commonly persist in legalization settings; evidence for ecological effects on other (e.g., property, violent) crimes is mixed. The prevalence of cannabis-impaired driving does appear to be steady or decreasing, while levels of cannabis involved in motor-vehicle-crashes, and overall motor-vehicle-crash fatality levels appear to have increased. In North American legalization settings, the legal sourcing of cannabis has gradually increased to involve 50–70% or more of consumers alongside expanding legal retail market proliferation, while found to be influenced by multiple factors (e.g., product characteristics, price, use intensity). Conversely, legal cannabis sourcing remains much more limited in Uruguay’s restrictive settings. Data on the evolution of illegal cannabis markets is very limited, suggesting some evidence for reductions of illegal production but also shifts or displacement effects (e.g., towards production for or distribution in non-legalization settings), leaving open questions as to the impacts of legalization in these domains. Overall, legalization appears to be meeting some of its socio-legal and specifically crime-reduction goals, yet while key data indicators are mixed or lacking. Focused and expanded research on crime-related outcomes of legalization policies is needed, also given limited benefits to date evidenced for health outcomes.

Les ‘Lignes Directrices Pour l'Usage du Cannabis à Moindre Risque (LUCMR)’: RECOMMENDATIONS [The ‘Lower-Risk Cannabis Use Guidelines (LRCUG)’: RECOMMENDATIONS (FRENCH)]

Article

Apr 2023
INT J DRUG POLICY

Die ‘Richtlinien für die Risiko-Reduzierung beim Cannabiskonsum (RRRCK)’: EMPFEHLUNGEN[The ‘Lower-Risk Cannabis Use Guidelines (LRCUG)’: RECOMMENDATIONS (GERMAN)]

Article

Mar 2023
INT J DRUG POLICY

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

Article

Full-text available

Aug 2021
INT J DRUG POLICY

Background 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. Methods 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. Results 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. Conclusions 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.

Prevalence and correlates of non-daily and daily cannabis use among persons 15 years and older in South Africa: results of a national survey in 2017

Article

Full-text available

Mar 2021
SUBST ABUSE TREAT PR

Background The study aimed to assess the prevalence and correlates of non-daily and daily cannabis use among persons 15 years and older in South Africa. Method In a national cross-sectional 2017 survey, 39,207 persons 15 years and older (Median = 34 years) responded to a questionnaire on cannabis use and health variables. Multinominal logistic regression was used to assess the determinants of nondaily and daily cannabis use among the general population and logistic regression for the determinants of daily cannabis use among active cannabis users. Results Results indicate that 5.0% of the participants engaged in non-daily and 2.8% in daily cannabis use in the past 3 months. In adjusted multinomial logistic regression analysis, male sex, Grade 8–11 education, Coloureds, alcohol use disorder, never married, and other drug use were positively associated with daily cannabis use while not in not labour force was negatively associated with daily cannabis use. Moreover, male sex, never married, alcohol use disorder, and other drug use were positively, while physical multimorbidity was negatively associated with nondaily cannabis use. In adjusted logistic regression, compared to nondaily cannabis users, daily cannabis users were more likely male and were less likely not in the labour force and were less likely using other drugs. Conclusion About one in ten participants had used cannabis in the past 3 months in South Africa. Several sociodemographic and health indicators were identified that were associated with non-daily and/or daily cannabis use.

Prevalence and correlates of non-daily and daily cannabis use among persons 15 years and older in South Africa: Results of a national survey in 2017

Preprint

Full-text available

Nov 2020

Background The study aimed to assess the prevalence and correlates of non-daily and daily cannabis use among persons 15 years and older in South Africa.Method In a national cross-sectional 2017 survey, 39,207 persons 15 years and older (Median = 34 years) responded to a questionnaire on substance use and health variables. Multinominal logistic regression was used to assess the determinants of nondaily and daily cannabis use and logistic regression for the determinants of daily cannabis use among active cannabis users.ResultsResults indicate that 5.0% of the participants engaged in non-daily and 2.8% in daily cannabis use in the past 3 months. In adjusted multinomial logistic regression analysis, male sex, having Grade 8–11 education, Coloureds, alcohol use disorder, living with husband or wife, not living with a partner, and other drug use were positively and students were negatively associated with daily cannabis use. Male sex, younger age, living alone or single, living with a partner, alcohol use disorder, and other drug use were positively and multimorbidity was negatively associated with nondaily cannabis use. Compared to nondaily cannabis users, male sex had higher odds and students and other drug use had lower odds of daily cannabis use.Conclusion About one in ten participants engaged past 3-month cannabis use, and several sociodemographic and health indicators were identified associated with non-daily and daily cannabis use.

Intensity of cannabis use: Findings from three online surveys

Article

May 2020
INT J DRUG POLICY

Background Drug use is often measured in terms of prevalence, meaning the number of people who used any amount in the last month or year, but measuring the quantity consumed is critical for making informed regulatory decisions and estimating the effects of policy changes. Quantity is the product of frequency (e.g., number of use days in the last month) and intensity (amount consumed per use day). Presently, there is imperfect understanding of the extent to which more frequent users also consume more intensively. Methods and data We examine cannabis flower consumption reported in three similar online surveys fielded in times and places where cannabis was and was not legal. These convenience samples returned enough valid responses (n = 2,618) to examine consumption across different frequencies of use via analyses of measures of central tendency, data visualizations, and multivariate regressions. Additional calculations incorporate data from the National Survey on Drug Use and Health. Findings Respondents who reported using daily (i.e., 30 days in the past month) consumed almost twice as much per day of use on average as did those reporting less than daily. We find only modest increases in intensity among those using less than daily, but then a substantial increase (p< 0.001) for those who use daily. Most respondents report that on heavy or light use days their consumption differs from a typical day of use by a factor of 2 or more, but only about 25% of days were described as heavy or light. We estimate those using cannabis 21+ days a month account for 80% of consumption vs. 71% of the days of use. Discussion Daily cannabis users consume more intensively than others, including near-daily users. When possible, survey questions should move beyond the presence or absence of use and number of days used.

A Baseline Review and Assessment of the Massachusetts Adult-Use Cannabis Industry: Market Data and Industry Participation

Article

Full-text available

Feb 2020

This report has been prepared in response to the enabling legislation, Chapter 55 of the Acts of 2017 section 17a (iii) to assess two items on the Cannabis Control Commissions’ research agenda. This legislation section states that: “The commission shall develop a research agenda in order to understand the social and economic trends of marijuana in the commonwealth, to inform future decisions that would aid in the closure of the illicit marketplace and to inform the commission on the public health impacts of marijuana.” This report responds to two of the research agenda priorities for the adult-use cannabis market: (1) ownership and employment trends in the marijuana industry examining participation by racial, ethnic and socioeconomic subgroups, including identification of barriers to participation in the industry; and (2) a market analysis examining the expansion or contraction of the illicit marketplace and the expansion or contraction of the legal marketplace, including estimates and comparisons of pricing and product availability in both markets.

Measuring the Association Between Cannabis Dispensary Density and Adult Consumption in a Statewide Setting: Does Urbanicity Matter?

Article

Full-text available

Feb 2025

Objective: This study used data from early stages of non-medical cannabis legalization in Washington State to 1) Compare cannabis dispensary density measures by urbanicity, 2) Test if dispensary density was associated with cannabis use overall and by urbanicity. Method: Data are from the Privatization of Spirits in Washington Surveys (n = 2,162 adults) and licensing records. We graphed six cannabis dispensary density measures by urbanicity. Logistic regressions tested if dispensary density was associated with 1) cannabis use at least bimonthly and 2) daily/near-daily cannabis use after adjusting for urbanicity. Regressions stratified by urbanicity determined whether associations differed in urban vs. suburban/rural areas. Results: Crude counts and counts per population were higher in suburban/rural areas. Counts per land area, counts in a 3- to 5-mile buffer, proximity, and clustering detected greater densities in urban areas. Monthly/bimonthly cannabis use was associated with counts per buffer in the full sample (aOR = 1.08 [1.02, 1.14]) and urban areas (aOR = 1.08 [1.02, 1.14]). Clustering was associated with monthly/bimonthly use in suburban/rural areas (aOR = 7.85 [1.31, 47.17]). Daily/near-daily use was associated with proximity and clustering in the full sample (proximity: aOR = 0.78 [0.64, 0.97]; clustering: aOR = 2.44 [1.32, 4.51]), urban areas (proximity: aOR = 0.67 [0.49, 0.92]; clustering: aOR = 2.29 [1.22, 4.32]), and suburban/rural areas (proximity: aOR = 0.66 [0.45, 0.97]; clustering: aOR = 11.10 [1.55, 79.36]). Conclusions: In Washington’s early non-medical cannabis market, dispensary availability (counts) was associated with monthly/bimonthly use. Accessibility (proximity) and clustering were associated with daily/near-daily use. Dispensary density thresholds and minimum distances between dispensaries may reduce regular and frequent cannabis use in Washington.

Quantity of delta-9-tetrahydrocannabinol consumption and cannabis use disorder among daily cannabis consumers

Article

Full-text available

Nov 2024
ADDICTION

Background and aims Amid escalating cannabis legalization and daily consumption in the United States (US), determining the risk of cannabis use disorder (CUD) and relevant consequences among daily consumers has become a public health priority. Understanding these risks requires valid assessment of the daily quantity of delta‐9‐tetrahydrocannabinol (THC) consumed and its relation to consequences. This study characterized daily cannabis consumption using a new method for estimating milligrams of THC (mgTHC), and examined the relationship between daily mgTHC and CUD severity in a large national sample of daily consumers. Design, setting and participants US adult (aged 18+ years) daily cannabis consumers ( n = 4134) completed a comprehensive online survey of cannabis consumption patterns (e.g. frequency, quantity, product types, potencies, administration methods) and Diagnostic and Statistical Manual of Mental Disorders , 5th edition (DSM‐5) CUD criteria. Measurements The primary exposure was past‐week daily mgTHC consumption, calculated from survey responses to queries about product type, amount and potency consumed and including adjustments for puff size and loss of THC from specific methods of administration. The primary outcomes were (1) number of CUD criteria (range = 0–11) and (2) CUD severity categories: none, mild, moderate, severe. Findings Median daily consumption was ~130 mgTHC, with substantial variability (25% ≤ 50 mg and 25% ≥ 290 mg). On average, participants endorsed 2.5 CUD criteria, and 65% met criteria for CUD (39% mild, 18% moderate, 8% severe). Greater daily mgTHC predicted higher CUD criteria count [beta log(mgTHC) = 0.50, 95% confidence interval (CI) = 0.267–0.734] and higher odds of mild [log odds ratio (logOR) = 0.238, 95% CI = 0.184–0.292], moderate (logOR = 0.303, 95% CI = 0.232–0.374) or severe (logOR = 0.335, 95% CI = 0.236–0.435) CUD. Conclusions Among daily consumers of cannabis, there appears to be a positive relationship between the daily quantity of cannabis consumed (measured in milligrams of delta‐9‐tetrahydrocannabinol) and both the risk and severity of cannabis use disorder.

Exploring survey methods for measuring consumption quantities of cannabis flower and concentrate products

Article

Full-text available

Sep 2023

Background: Researchers need accurate measurements of cannabis consumption quantities to assess risks and benefits. Survey methods for measuring cannabis flower and concentrate quantities remain underdeveloped.Objective: We examined "grams" and "hits" units for measuring flower and concentrate quantities, and calculating milligrams of THC (mgTHC).Methods: Online survey participants (n = 2,381) reported preferred unit (hits or grams), past-week hits and grams for each product, and product %THC. Quantile regression compared mgTHC between unit-preference subgroups. Hits-based mgTHC calculations assumed a universal grams-per-hit ratio (GPHR). To examine individualized GPHRs, we tested a "two-item approach," which divided total grams by total hits, and "one-item approach," which divided 0.5 grams by responses to the question: "How many total hits would it take you to finish 1/2 g of your [product] by [administration method]?"Results: Participants were primarily daily consumers (77%), 50% female sex, mean age 39.0 (SD 16.4), 85% White, 49% employed full-time. Compared to those who preferred the hits unit, those who preferred the grams unit reported consuming more hits and grams, higher %THC products, and consequently, larger median mgTHC (flower-hits mgTHC: 32 vs. 91 (95%CI: 52-67); flower-grams mgTHC: 27 vs. 113 (95%CI: 73-95); concentrate-hits mgTHC: 29 vs. 59 (95%CI: 15-43); concentrate-grams mgTHC: 61 vs. 129 (95%CI: 43-94)). "Two-item" and "one-item" approach GPHRs were similar and frequently 50% larger or smaller than the universal GPHR.Conclusion: Allowing respondents to choose "hits" or "grams" when reporting cannabis quantities does not compromise mgTHC estimates. A low-burden, one-item approach yields individualized "hit sizes" that may improve mgTHC estimates.

Psychoactive drugs and male fertility: impacts and mechanisms

Article

Full-text available

Jul 2023
REPROD BIOL ENDOCRIN

Although psychoactive drugs have their therapeutic values, they have been implicated in the pathogenesis of male infertility. This study highlights psychoactive drugs reported to impair male fertility, their impacts, and associated mechanisms. Published data from scholarly peer-reviewed journals were used for the present study. Papers were assessed through AJOL, DOAJ, Google Scholar, PubMed/PubMed Central, and Scopus using Medical Subjects Heading (MeSH) indexes and relevant keywords. Psychoactive drugs negatively affect male reproductive functions, including sexual urge, androgen synthesis, spermatogenesis, and sperm quality. These drugs directly induce testicular toxicity by promoting ROS-dependent testicular and sperm oxidative damage, inflammation, and apoptosis, and they also suppress the hypothalamic-pituitary–testicular axis. This results in the suppression of circulating androgen, impaired spermatogenesis, and reduced sperm quality. In conclusion, psychoactive drug abuse not only harms male sexual and erectile function as well as testicular functions, viz., testosterone concentration, spermatogenesis, and sperm quality, but it also alters testicular histoarchitecture through a cascade of events via multiple pathways. Therefore, offering adequate and effective measures against psychoactive drug-induced male infertility remains pertinent.

Differentiating people who use cannabis heavily through latent class analysis

Article

Full-text available

Jun 2023
SUBST ABUSE TREAT PR

Background: People who use cannabis daily or near-daily vary considerably in their daily dosage and use frequency, impacting both experienced effects and adverse consequences. This study identified heavy cannabis user groups according to consumption patterns and factors associated with class membership. Methods: We conducted a cross-sectional study of 380 Spanish residents (61.8% male; average age = 30.3 years) who had used cannabis ≥ 3 days/week throughout the past year. Participants were recruited through chain referral and cannabis social clubs. We applied latent class analysis (LCA) to cluster participants according to use intensity. LCA indicators included frequency of weekly cannabis use, joints smoked each day, cannabis dosage, and if cannabis was consumed throughout the day or only at specific times. Associations between class membership and socio- demographics, use patterns, motives, supply sources, adverse outcomes, and use of other substances were measured using ANOVA and chi-squared tests. Multinomial regression identified the factors associated with latent class membership. Results: Three latent classes (moderately heavy: 21.8%, heavy: 68.2%, very heavy: 10%) had average weekly cannabis intakes of 2.4, 5.5, and 18.3 g, respectively. Very heavy users were older (χ2=17.77, p<0.01), less educated (χ2=36.80, p < 0.001), and had used cannabis for longer (F = 4.62, p = 0.01). CAST scores (F = 26.51, p < 0.001) increased across the classes. The prevalence of past-month alcohol use was lower among the heaviest users ( χ2 =5.95, p = 0.05). Cannabis was usually obtained from a club by very heavy users (χ2=20.95, p<0.001). Conclusions: People who use cannabis heavily present three groups according to frequency and quantity of cannabis consumption. Use intensity is associated with increased cannabis-related problems. Differences among heavy users must be considered in harm reduction interventions in cannabis clubs and indicated prevention.

Cannabis Use in Physicians: A Systematic Review and Meta-Analysis

Article

Full-text available

Apr 2023

Background: Cannabis use by physicians can be detrimental for them and their patients. We conducted a systematic review and meta-analysis on the prevalence of cannabis use by medical doctors (MDs)/students. Method: PubMed, Cochrane, Embase, PsycInfo and ScienceDirect were searched for studies reporting cannabis use in MDs/students. For each frequency of use (lifetime/past year/past month/daily), we stratified a random effect meta-analysis depending on specialties, education level, continents, and periods of time, which were further compared using meta-regressions. Results: We included 54 studies with a total of 42,936 MDs/students: 20,267 MDs, 20,063 medical students, and 1976 residents. Overall, 37% had used cannabis at least once over their lifetime, 14% over the past year, 8% over the past month and 1.1 per thousand (‰) had a daily use. Medical students had a greater cannabis use than MDs over their lifetime (38% vs. 35%, p < 0.001), the past year (24% vs. 5%, p < 0.001), and the past month (10% vs. 2%, p < 0.05), without significance for daily use (0.5% vs. 0.05%, NS). Insufficient data precluded comparisons among medical specialties. MDs/students from Asian countries seemed to have the lowest cannabis use: 16% over their lifetime, 10% in the past year, 1% in the past month, and 0.4% daily. Regarding periods of time, cannabis use seems to follow a U-shape, with a high use before 1990, followed by a decrease between 1990 and 2005, and a rebound after 2005. Younger and male MDs/students had the highest cannabis use. Conclusions: If more than a third of MDs tried cannabis at least once in their lifetime, this means its daily use is low but not uncommon (1.1‰). Medical students are the biggest cannabis users. Despite being common worldwide, cannabis use is predominant in the West, with a rebound since 2005 making salient those public health interventions during the early stage of medical studies.

Legal sourcing of ten cannabis products in the Canadian cannabis market, 2019–2021: a repeat cross-sectional study

Article

Full-text available

Feb 2023

Background One of the objectives of cannabis legalization in Canada is to transition consumers from the illegal to the legal market. Little is known about how legal sourcing varies across different cannabis product types, provinces, and frequency of cannabis use. Methods Data were analyzed from Canadian respondents in the International Cannabis Policy Study, a repeat cross-sectional survey conducted annually from 2019 to 2021. Respondents were 15,311 past 12-month cannabis consumers of legal age to purchase cannabis. Weighted logistic regression models estimated the association between legal sourcing (“all”/ “some”/ “none”) of ten cannabis product types, province, and frequency of cannabis use over time. Results The percentage of consumers who sourced “all” their cannabis products from legal sources in the past 12 months varied by product type, ranging from 49% of solid concentrate consumers to 82% of cannabis drink consumers in 2021. The percentage of consumers sourcing “all” their respective products legally was greater in 2021 than 2020 across all products. Legal sourcing varied by frequency of use: weekly or more frequent consumers were more likely to source “some” (versus “none”) of their products legally versus less frequent consumers. Legal sourcing also varied by province, with a lower likelihood of legal sourcing in Québec of products whose legal sale was restricted (e.g., edibles). Conclusion Legal sourcing increased over time, demonstrating progress in the transition to the legal market for all products in the first three years of legalization in Canada. Legal sourcing was highest for drinks and oils and lowest for solid concentrates and hash.

On offer to Ontario consumers three years after legalization: A profile of cannabis products, cannabinoid content, plant type, and prices

Article

Full-text available

Feb 2023

Introduction Cannabis was legalized in Canada in October 2018, regulating the production, distribution, sale, and possession of dried cannabis and cannabis oils. Additional products were legalized 1 year later, including edibles, concentrates, and topicals, with new lines of commercial products coming to market. Ontario is the most populous province in Canada and has the largest cannabis market with the highest number of in-person retail stores and the most cannabis products available online. This study aims to create a profile of products available to consumers three years after legalization by summarizing types of products, THC and CBD potency, plant type, and prices of product sub-categories. Methods We extracted data from the website of the Ontario Cannabis Store (OCS)—the public agency overseeing the only online store and sole wholesaler to all authorized in-person stores—in the first quarter of 2022 (January 19–March 23). We used descriptive analyses to summarize the data. A total of 1,771 available products were mapped by route of administration into inhalation (smoking, vaping, and concentrates), ingestible (edibles, beverages, oils, and capsules) and topical. Results Most inhalation products included ≥20%/g THC (dried flower: 94%; cartridges: 96%; resin: 100%) while ingestible products had similar proportions of THC and CBD content. Indica-dominant products tend to be more prominent in inhalation products while sativa-dominant products tend to be more prominent in ingestible products. The average sale price of cannabis was 9.30

/g for dried flower, 5.79

/0.1g for cartridges, 54.82

/g for resin, 3.21

/unit for soft chews, 1.37

/ml for drops, 1.52

/unit for capsules, and 39.94 $/product for topicals. Discussion In summary, a wide variety of cannabis products were available to Ontarians for different routes of administration and provides numerous indica-dominant, sativa-dominant, and hybrid/blend options. The current market for inhalation products however is geared towards the commercialization of high-THC products.

Typical Hits, Grams, or Joints: Evaluating Cannabis Survey Measurement Strategies for Quantifying Consumption

Article

Dec 2022

Aim: Standardized survey measures that capture diverse cannabis consumption patterns are needed to inform public health and policy. Our team is developing a flexible, personalized, low-burden survey item inventory to measure cannabis use patterns and estimate milligrams of THC (mgTHC) consumption in large samples. This study aimed to identify measurement gaps and analysis implications associated with an initial pool of candidate items that assessed use of cannabis flower and concentrate products (smoked and/or vaporized). Methods: Adult cannabis consumers (n=4247) completed an online survey assessing cannabis use frequency, quantity, product types, product potencies (%THC), and methods of administration. Participants chose to report their consumption quantities using one of three units: "hits per day," "grams per week," or "joints per week." Respondents also indicated whether their past 7-day consumption pattern represented their typical pattern. Results: Eighty-one percent had used cannabis daily in the past week. Thirty-two percent, 53%, and 15% chose to report flower and concentrate consumption quantity in hits, grams, and joints, respectively. Approximately 80-90% of responses for the number of hits, grams, and joints consumed were less than the maximum response option-suggesting that response options captured the full range of potential cannabis consumption behaviors. Those who chose grams or joints units were generally more likely to endorse higher risk cannabis use (e.g., morning use, high %THC products) in the past week than those who chose the hits unit (adjusted Odds Ratio range: 1.2-3.9). Among those who reported that the past week represented their typical behavior (83%), past 30-day and past 7-day frequencies were highly correlated (Spearman's Rho=0.77)-supporting the feasibility of using lower burden "typical week" items to extrapolate patterns beyond a 1-week time frame. Conclusion: Results from this online convenience sample of frequent cannabis consumers suggest that the current items yield coherent and expected response patterns. Although additional testing is required, a standardized, flexible survey instrument for large-scale assessment of cannabis patterns and calculation of mgTHC seems within reach.

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

Article

Full-text available

Oct 2022
PLOS ONE

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.

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

Preprint

Full-text available

May 2022

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-legalisation. 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.

Reasons for Purchasing Cannabis From Illegal Sources in Legal Markets: Findings Among Cannabis Consumers in Canada and U.S. States, 2019-2020

Article

May 2022
J STUD ALCOHOL DRUGS

Objective: Nonmedical cannabis is legal in Canada and several U.S. states. Displacing the illegal market is a primary goal of legalization; however, there are little data on factors that predict consumers' transition from the illegal to the legal market. The current study aimed to examine reasons for purchasing illegal cannabis and, thus, potential barriers to purchasing legal cannabis among consumers in Canada and U.S. states. Method: Data are from the 2019 and 2020 International Cannabis Policy Study, a repeat cross-sectional survey conducted among 16- to 65-year-olds. Reasons for purchasing illegally in the past 12 months were asked of male and female cannabis consumers in Canada and U.S. legal states (n = 11,659). Changes over time in reasons for illegal purchasing were tested. Analyses among Canadians also examined associations between reasons for illegal purchasing and objective data on cannabis prices and retail density. Results: In both years, the most commonly reported barriers to legal purchasing were price (Canada: 35%-36%; United States: 27%) and inconvenience (Canada: 17%-20%; U.S.: 16%-18%). In 2020 versus 2019, several factors were less commonly reported as barriers in Canada, including inconvenience (17% vs. 20%, p = .011) and location of legal sources (11% vs. 18%, p < .001). Certain barriers increased in the United States, including slow delivery (5% vs. 8%, p = .002) and requiring a credit card (4% vs. 6%, p = .008). In Canada, consumers in provinces with more expensive legal cannabis were more likely to report price as a barrier, and those in provinces with fewer legal retail stores were more likely to report inconvenience as a barrier (p < .001). Conclusions: Higher prices and inconvenience of legal sources were common barriers to purchasing legal cannabis. Future research should examine how perceived barriers to legal purchasing change as legal markets mature.

Online Knowledge Translation Program involving Video Games and University Student-Led Tutorials about Cannabis and Psychosis for Black Youth: Mixed Method Feasibility Study (Preprint)

Article

Full-text available

Sep 2021

Background: Youth from some Black racialized communities may benefit from a youth-centered approach to educate them about risks associated with underage use. Youth are generally unaware of the research linking underage cannabis use and the risk of subsequent psychosis symptoms. We have piloted a new online knowledge translation program consisting of facilitated tutorials and video games to address this gap. During tutorials, undergraduate students provided scientific knowledge about the association between underage use and the risk of psychosis. The video games [the Back to Reality SERIES] were inspired by research about young people experiencing a first episode of psychosis. Objective: Because very little is known about the acceptability, and feasibility of programs educating Black youth about cannabis and psychosis risk, this knowledge translation program was evaluated to assess whether differences in knowledge acquisition could be detected before and after the program. Methods: This feasibility study used mixed methods to evaluate the transfer of knowledge about cannabis and psychosis before and after the online knowledge translation program using a quiz. Qualitatively inquiry explored participant satisfaction with the program. Eligible participants were 16 to 19 years of Black African or Caribbean descent. After playing the psychoeducational video games, participants attended two tutorial group sessions about cannabis and psychosis led by trained undergraduate students. The tutorials augmented the educational content inspired by the gameplay: participants discussed what they learned from the video games and their understanding of psychosis and the effects of cannabis. Knowledge acquisition was measured using a quiz (PCT: Psychosis Cannabis Test) before and after the knowledge translation program. Undergraduate students qualitatively analyzed the tutorial discussions for themes, and the pre-/post -quiz scores were analyzed using t-tests for significant differences in scores. Results: Nine Black youth were recruited and completed this pilot study. The mean PCT scores were 5.67 (+ 1.7) and 7.78 (+ 1.8) before and after the knowledge translation program, respectively. Participants had significantly higher scores (P<.05) post-knowledge translation program. Thematic analysis of the facilitated tutorials and interviews revealed three major themes: Video game satisfaction, marijuana and psychosis literacy, and help-seeking awareness. Overall, participants showed an increased awareness and understanding of the subject matter after the gameplay and tutorial intervention. Conclusions: When supplemented with tutorial sessions, the Back to Reality Series shows promise for addressing the gap in knowledge about cannabis and psychosis, and the results provide preliminary evidence that the games appeal to Black youth. Clinicaltrial:

A Systematic Review and Narrative Synthesis of the Evolution of Adolescent and Young Adult Cannabis Consumption Before and After Legalization

Article

Mar 2022

Purpose: To systematically review evidence assessing the evolution of cannabis consumption before and after the implementation of non-medical cannabis legislation. Methods: MEDLINE, PubMED, PsycINFO, Scopus, and Web of Science were systematically searched for studies that examined change in cannabis consumption before and after nonmedical cannabis legislation. Data were tabulated by study design, levels of consumption, and individual subgroups. Data were analyzed using a narrative synthesis approach, considering study quality. Results: 32 studies were included (11 higher quality and 21 lower quality). 40% of higher quality evidence supported an increase in postlegalization consumption (55% did not report a change and 5% reported a decrease). The increase was most evident for young adults (42% of higher quality evidence) and in the consumption in the past month (37% of higher quality evidence). There was limited supporting evidence for new users having grown in response to legalization. Based on subgroup analysis, the increase in postlegalization consumption was higher among women and those who engage in binge-drinking. Conclusions: Higher quality evidence suggests an increase in adolescent past-month consumption of cannabis following legalization in several geographical jurisdictions. Consumption evolution prelegalization and postlegalization differed by age group and for young women and for binge drinkers. Consumption evolution differences suggest a variety of strategies might be required in efforts to lower public health impacts of cannabis consumption following legalization.

Changes in Cannabis Consumption Among Emerging Adults in Relation to Policy and Public Health Developments

Article

Full-text available

Feb 2022

Background: Rates of cannabis use appear to be highest among emerging adults (EA). Evidence suggests that cannabis smoking, as well as alternate methods of cannabis use (e.g., vaping, edibles) have become a prevalent mode of consumption among this population. Substance use or misuse peaks during emerging adulthood and may be influenced by extreme economic, social and community developments, such as policy changes, public health concerns, and significant global events such as pandemics. For instance, it is highly likely that cannabis consumption trends among at-risk populations were influenced by the legalization of recreational cannabis in Canada, the declaration of the “e-cigarette or vaping product use associated lung injury” or “EVALI” outbreak, and the “COVID-19” pandemic. Objectives: We aimed to examine self-reported changes in frequency of cannabis use among EA in Canada (N = 312): pre-legalization, post-legalization; pre-EVALI, post-EVALI; pre-COVID-19, since-COVID-19. Results: There was a gradual increase in average frequency of smoking and vaping cannabis across the six different time intervals from the pre-legalization period (2018) to the COVID-19 pandemic period (2020). Males reported higher frequencies of cannabis smoking and vaping compared to females. Conclusions: Despite health concerns and expectations that EVALI and COVID-19 events would lead to decreased consumption, our results suggest an average increase in smoking and vaping cannabis, although the most notable increase was after legalization. There are important sex differences in behavioral factors of cannabis use in EA, though it appears that the “gender-gap” in cannabis consumption is closing. These findings may facilitate the development of intervention programs for policy measures to address cannabis-attributable outcomes in the face of contextual factors that promote use, such as public emergencies or changes in policy landscapes.

Cannabis flower prices and transitions to legal sources after legalization in Canada, 2019-2020

Article

Dec 2021
DRUG ALCOHOL DEPEN

Background The post-tax price of legal cannabis has the potential to influence whether consumers transition from the illegal to legal cannabis market. The aims of the study were to: 1) estimate the percentage who report purchasing dried flower at different sources; 2) estimate the unit price of dried flower; and 3) examine the association between price and legality of purchase source. Methods Repeat cross-sectional survey data come from Canadian respondents from the International Cannabis Policy Study conducted in 2019 and 2020. Respondents were recruited through online commercial panels, of legal age to purchase cannabis (up to 65 years), and purchased dried flower in the past 12-months (n=4,923). Weighted binary logistic regression models examined the association between price and legality of source. Results The proportion of consumers last purchasing dried flower from legal sources increased from 2019 to 2020 (45.7% vs 58.1%) and in the past 12-months, the average percent of dried flower consumers reported purchasing from legal sources increased from 2019 to 2020 (55.7% vs 67.5%). The mean price of legal dried flower decreased in 2020 (

12.63 vs

11.16; p<0.001), but remained more expensive than illegal dried flower in both years (

12.63 vs

9.04 in 2019; p<0.001,

11.16 vs

9.41 in 2020; p<0.001). Conclusions Two years after legalization in Canada, the price of dried flower from legal sources decreased, along with a greater percentage of consumers purchasing from legal sources than after one year. Price and retail policies must continue to encourage the transition to the legal market in Canada.

Public health monitoring of cannabis use in Europe: prevalence of use, cannabis potency, and treatment rates

Article

Full-text available

Sep 2021

Background Cannabis is one of the most widely used substances worldwide. Heavy use is associated with an increased risk of cannabis use disorders, psychotic disorders, acute cognitive impairment, traffic injuries, respiratory problems, worse pregnancy outcomes, and there are indications for genotoxic and epigenotoxic adverse effects. International regulation of medical and non-medical cannabis use is changing rapidly and substantially, highlighting the importance of robust public health monitoring. This study aimed to describe the trends of key public health indicators in European Union (27 member states + UK, Norway and Turkey) for the period 2010 to 2019, their public health implications, and to identify the steps required to improve current practice in monitoring of cannabis use and harm in Europe. Methods Data on four key cannabis indicators (prevalence of use, prevalence of cannabis use disorder [CUD], treatment rates, and potency of cannabis products) in Europe were extracted from the United Nations Office on Drugs and Crime, European Monitoring Centre for Drugs and Drug Addiction and the Global Burden of Disease study. For prevalence of use and CUD, the first and last available estimate in each country were compared. For treatment rates and cannabis potency, linear regression models were conducted. Findings Between 2010 and 2019, past-month prevalence of cannabis use increased by 27% in European adults (from 3·1 to 3·9%), with most pronounced relative increases observed among 35-64 year-olds. In 13 out of 26 countries, over 20% of all past-month users reported high-risk use patterns. The rate of treatment entry for cannabis problems per 100,000 adults increased from 27·0 (95% CI: 17·2 to 36·8) to 35·1 (95% CI: 23·6 to 46·7) and has mostly plateaued since 2015. Modest increases in potency were found in herbal cannabis (from 6·9% to 10·6% THC) while median THC values tripled in cannabis resin (from 7·6% to 24·1% THC). Interpretation In the past decade, cannabis use, treatment rates and potency levels have increased in Europe highlighting major concerns about the public health impact of cannabis use. Continued monitoring and efforts to improve data quality and reporting, including indicators of high-risk use and cannabis-attributable harm, will be necessary to evaluate the health impact of international changes in cannabis regulation. Funding This study received no specific funding.

Much Ado about Dosing: The Needs and Challenges of Defining a Standardized Cannabis Unit

Article

Full-text available

Jun 2021

A definition of a standardized cannabis unit is needed to accelerate research in medical cannabis and enable safe and effective use of medical cannabis products. A standardized cannabis unit should incorporate several factors, such as plant-related aspects (e.g., varied cannabinoid concentrations in Cannabis sativa) and product attributes, such as different administration routes and cannibinoid concentrations. Furthermore, different intentions for the use and desired subjective effects also influence the dose needed for the intended effect. Many barriers remain in defining a standardized unit for cannabis (e.g., different delivered doses and pharmacokinetics depending on the administration route) and pathophysiological factors that can impact the response to the therapy or side-effect profile. A recent proposal for a standardized tetrahydrocannabinol (THC) unit by Freeman and Lorenzetti, which defines a “Standard THC Unit” of 5 mg THC, presents a sophisticated approach to support safe, nonmedical cannabis consumption within the same administration route. However, this approach may be limited when considering medical cannabis products, given a need to track efficacy and safety, a variety of products available, and the need to understand the composition of other cannabinoids. Further efforts in developing a standardized cannabis unit are needed to capture the medical cannabis perspective, possibly including the antagonizing effect of cannabidiol on THC, the role of the entourage effect, and the relationship between pharmacokinetic profiles and therapeutic effects of cannabis constituents.

We can't rely upon monitoring by researchers and civil society to prevent cannabis industry influence—a global response is needed

Article

May 2021

Sally Casswell

Daily, but not occasional, cannabis use is selectively associated with more impulsive delay discounting and hyperactive ADHD symptoms in binge-drinking young adults

Article

Full-text available

Jul 2021
PSYCHOPHARMACOLOGY

Rationale There is increasing interest in and evidence for the negative impacts of cannabis use in cognitive performance and symptoms of attention-deficit/hyperactivity disorder (ADHD), with age of first cannabis use as a potential amplifier of these associations. However, the existing literature is inconsistent, which may be due to methodological limitations, including small sample sizes. Objective To examine current cannabis use and age of first cannabis use in relation to neurocognitive task performance and ADHD symptoms in a large sample of binge-drinking young adults. Methods Participants were young adults (N=730, M age=21.44, 52.6% female) assessed for current cannabis use, neurocognitive task performance, and ADHD symptoms. Three-group ANCOVAs compared individuals reporting frequent (daily/multiple times daily), occasional (weekly/monthly), or no cannabis use. Results Covarying alcohol use, tobacco use, age, sex, income, and education, daily cannabis users exhibited significantly more impulsive delay discounting and hyperactive-impulsive ADHD symptoms compared to both other groups. However, cannabis use was not associated with inattentive ADHD symptoms, verbal intelligence, working memory, probability discounting, short-term verbal memory, or behavioral inhibition. Age of initiation of cannabis use exhibited neither main effects nor interactions in relation to any domains of cognitive performance or ADHD symptomatology. Conclusions The current findings provide support for a link between cannabis use in relation to immediate reward preference and symptoms of hyperactive-impulsive ADHD in young adults, but only among frequent users. No other neurocognitive domains exhibited associations with cannabis and age of first use was neither independently nor interactively associated with cognitive outcomes.

Response to Manthey, Carr, and Rehm

Article

Nov 2019
DRUG ALCOHOL DEPEN

Effekte der Cannabislegalisierung. Empirische Forschungen aus Kanada, Uruguay und den USA

Chapter

Jan 2024

Ole Bartels

Drogen und Sucht. Eine Einführung (Reihe: Kriminologisches Basiswissen)

Book

Jul 2024

Henning Schmidt-Semisch

Nicht erst die jüngsten Diskussionen zu Cannabis zeigen, dass die Themen Drogen und Sucht polarisieren. Dabei werden die verschiedenen Drogen (etwa Alkohol, Cannabis oder Heroin) moralisch und rechtlich völlig unterschiedlich bewertet, wobei diese Bewertungen sich von Kultur zu Kultur unterscheiden und auch historisch äußerst wandelbar sind. In vielen Bereichen dominiert weiterhin eine kriminal- und sicherheitspolitische Herangehensweise, wobei zunehmend aber auch gesundheitspolitische Überlegungen im Sinne einer akzeptierenden Drogenpolitik relevant werden. Der Band führt in grundlegende Aspekte aus den Bereichen Drogen und Sucht ein und gibt einen kompakten, informativen Überblick über wichtige Etappen und wissenschaftliche Befunde zu Drogengeschichte, Drogenforschung und Drogenpolitik.

Das Sucht-Konzept und seine Nebenwirkungen

Chapter

Jul 2024

Henning Schmidt-Semisch

Individual differences in legal and illicit cannabis purchasing behaviour in British Columbia, Canada: Findings from a 2021 cross-sectional survey

Article

Feb 2024

Myles A Maillet

Income inequality and daily use of cannabis, cigarettes, and e-cigarettes among Canadian secondary school students: Results from COMPASS 2018-19

Article

Mar 2023

Introduction: Cannabis, cigarette, and e-cigarette use among Canadian adolescents is a major public health concern. Income inequality has been associated with adverse mental health among youth and may contribute to the risk of frequent cannabis, cigarette, and e-cigarette use. We tested the association between income inequality and the risk of daily cannabis, cigarette, and e-cigarette use among Canadian secondary school students. Methods: We used individual-level survey data from Year 6 (2018/19) of Cannabis, Obesity, Mental health, Physical activity, Alcohol use, Smoking, and Sedentary Behavior (COMPASS) and area-level data from the 2016 Canadian Census. Three-level logistic models were used to assess the relationship between income inequality and adolescent daily and current cannabis use, cigarette smoking, and e-cigarette use. Results: The analytic sample included 74,501 students aged 12-19. Students were most likely to report being male (50.4%), white (69.1%), and having weekly spending money over $100 (23.5%). We found that a standard deviation unit increase in Gini coefficient was significantly associated with increased likelihood of daily cannabis use (OR=1.25, 95% CI = 1.01-1.54) when adjusting for relevant covariates. We found no significant relationship between income inequality and daily smoking. While Gini was not significantly associated with daily e-cigarette use, we observed a significant interaction between Gini and gender (OR=0.87, 95% CI= 0.80-0.94), indicating that increased income inequality was associated with higher risk of reporting daily e-cigarette use among females only. Discussion: An association between income inequality and the likelihood of reporting daily cannabis use across all students and daily e-cigarette use in females were observed. Schools in higher income inequality areas may benefit from targeted prevention and harm reduction programs. Results emphasize the need for upstream discussion on policies that can mitigate the potential effects income inequality.

Differentiating heavy cannabis users through latent class analysis

Preprint

Full-text available

Jan 2023

Background: Daily or near-daily cannabis users vary considerably in their daily dosage and use frequency, impacting both experienced effects and adverse consequences. This study identified heavy cannabis user groups according to consumption patterns and factors associated with class membership. Methods: We conducted a cross-sectional survey of 400 Spanish residents (62.2% male; average age=29.6 years) who had used cannabis ≥3 days/week throughout the past year. Participants were recruited through chain referral and cannabis social clubs. We applied latent class analysis (LCA) to cluster participants according to use intensity. Associations between class membership and socio-demographics, use patterns, motives, supply sources, adverse outcomes, and use of other substances were measured using ANOVA and chi-squared tests. Multinomial regression identified the factors associated with latent class membership. Results: Three latent classes (moderately heavy: 23%, heavy: 67.5%, very heavy: 9.5%) had average weekly cannabis intakes of 2.3, 5.6, and 18.3 grams, respectively. Age, education, years of use, buying cannabis in a club, Cannabis Abuse Screening Test (CAST) scores, and cocaine use were associated with cannabis use intensity. Very heavy users were older ( X² =20.44, p<0.01), less educated X²=28.92, p<0.001), and had used cannabis for longer (F=6.80, p=0.001). The prevalence of past-month cocaine use ( X² =13.90, p<0.05) and CAST scores (F=25.73, p<0.001) increased across the classes. Cannabis was usually obtained from a club by very heavy users ( X² =24.40, p<0.001). Conclusions: Heavy cannabis users are heterogenous and present several groups according to frequency and quantity of cannabis consumption. Use intensity is associated with increased cannabis use disorders and dependence.

Menores y consumo de cannabis: un análisis por género y edad

Article

Full-text available

Dec 2022

Menores y consumo de cannabis: un análisis por género y edad Minors and cannabis use: an analysis by gender and age El consumo de cannabis sigue constituyendo a día de hoy uno de los principales problemas de salud pública en la población juvenil tanto española como europea. A las elevadas prevalencias de consumo actuales se unen nuevos formatos y nuevos rituales de consumo, niveles de THC significativamente mayores y edades de inicio especialmente tempranas, lo cual suscita una creciente preocupación social, especialmente cuando nos referimos a adolescentes. El presente trabajo, llevado a cabo con una muestra de casi 4.000 estudiantes de 12 a 17 años de la comunidad gallega, no sólo permite constatar los elevados niveles de consumo existentes a edades tempranas y tasas de consumo problemático alarmantes, sino que evidencia la interesante interacción entre las variables género y edad, que se da en las fases iniciales del consumo. Asumir que en términos generales puede haber o no diferencias de género en el consumo de cannabis implica ignorar el papel de las normas y roles de género en los procesos de socialización de las y los adolescentes. De forma más concreta, se ha constatado niveles de consumo y consumo problemático (evaluado a través del CAST) significativamente mayores entre las chicas a los 14-15 años, produciéndose una progresiva masculinización del consumo de cannabis a partir de dicha edad. Estos resultados poseen interesantes implicaciones a la hora de diseñar nuevas estrategias y políticas de prevención.

Addiction and human male fertility: A systematic review and a critical appraisal

Article

May 2022

Background: Addiction is a global problem that has many negative consequences on human health as well as the quality of life. Objectives: This review aimed to assess the effect of addiction on human male fertility. Methods: A systematic review was conducted on various electronic sites. Results: The initial literature search identified a total of 5239 articles in all searched databases. After removing duplicates and application of inclusion/exclusion criteria,177 were potential articles, 112 were omitted because no direct relevance was encountered. Finally, 65 studies were retained for review. They were classified according to the type of addiction into; opioids and cannabinoids (18 articles), alcohol (7 articles), cocaine (2 articles), Androgenic Anabolic steroids AAS (15 articles), tobacco (10 articles) and caffeine (13 articles). Most of these recruited articles demonstrated a negative impact of the addressed substance on male fertility with variable levels of evidence. Conclusions: It was concluded that addiction harms human male fertility that should be put into consideration. More future studies are needed after a proper methodological and statistical approach, including logistic regression analysis, to predict the effect of a specific substance on human male fertility. This article is protected by copyright. All rights reserved.

Exploring cannabis use and perspectives among psoriatic disease patients

Article

Jan 2022

Objective: To assess the correlation between cannabis use and psoriatic disease severity, health-related quality of life, pain, psychosocial outcomes, and cytokine levels in psoriasis (PsC) and psoriatic arthritis (PsA) patients. Methods: PsC and PsA patients enrolled in the International Psoriasis and Arthritis Research Team (IPART) program were surveyed on cannabis use and were asked to provide a serum and urine sample. Demographic and clinical variables were compared between users and non-users using Student's t-test or Mann-Whitney U test for continuous variables, and chi-square or Fisher's exact test for categorical variables. Results: Of 151 respondents, 30% reported current cannabis use within the last year. Compared to non-users, cannabis users were younger and had a shorter PsA duration and poorer mental health as measured by the SF-36. Other measures of health-related quality of life and pain were comparable between the groups. Respondents' primary perceived benefits of cannabis use were aid in sleep and arthritis pain relief, but there was no difference in pain between users and non-users. No THC was detected in the urine of non-users while users had a mean level of 19.6 ng/ml. Serum IL-23 levels were statistically significantly higher in non-users than in users. Conclusion: A third of the patients used cannabis within the past year, and 54.3% of users reported the use of cannabis for arthritis pain relief. However, there was no difference in pain scores. Comprehensive education for providers on the current body of evidence and further studies on cannabis use and outcomes in psoriatic disease are needed. Key Points • A third of patients with psoriatic arthritis have used cannabis in the past year. • Most used it for better sleep and control of pain. • There was no difference in pain scores between users and non-users. • IL-23 levels were significantly higher in non-users.

Objective Identification of Cannabis Use Levels in Clinical Populations Is Critical for Detecting Pharmacological Outcomes

Article

Nov 2021

Introduction: Cannabis is widely used for recreational and medical purposes, but its therapeutic efficacy remains unresolved for many applications as data from retrospective studies show dramatic discrepancy. We hypothesized that false self-reporting of cannabis use and lack of differentiation of heavy users from light or occasional users contribute to the conflicting outcomes. Objective: The goal of this study was to develop an objective biomarker of cannabis use and test how application of such biomarker impacts clinical study outcomes and dose-response measures. Methods and Analysis: Population pharmacokinetic (PK) models of (-)-trans-Δ9-tetrahydrocannabinol (THC) and its metabolites 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (11-COOH-THC) were developed based on published studies reporting cannabinoid disposition in individual subjects following intravenous administration or smoking of cannabis. Plasma 11-COOH-THC concentration distributions in different cannabis user groups smoking cannabis were generated via Monte Carlo simulations, and plasma concentration cutoff values of 11-COOH-THC were developed to differentiate light and heavy daily cannabis users in clinical studies. The developed cutoff value was then applied to a retrospective study that assessed the impact of cannabis use on T cell activation in subjects with HIV who self-reported as either nonuser or daily user of cannabis. Results: The developed population PK models established plasma 11-COOH-THC concentration of 73.1 μg/L as a cutoff value to identify heavy daily users, with a positive predictive value of 80% in a mixed population of equal proportions of once daily and three times a day users. The stratification allowed detection of changes in T cell activation in heavy users which was not detected based on self-reporting or detectability of plasma cannabinoids. A proof-of-concept power analysis demonstrated that implementation of such cutoff value greatly increases study power and sensitivity to detect pharmacological effects of cannabis use. Conclusions: This study shows that the use of plasma 11-COOH-THC concentration cutoff value as an objective measure to classify cannabis use in target populations is critical for study sensitivity and specificity and provides much needed clarity for addressing dose-response relationships and therapeutic effects of cannabis.

How Well Is Cannabis Legalization Curtailing the Illegal Market? A Multi-wave Analysis of Canada’s National Cannabis Survey

Article

Jul 2021

In 2018, the government of Canada legalized cannabis for non-medical use. In addition to safeguarding public health, the main objective was to divert profits from the illicit market and restricting its availability to youth. This dramatic shift in policy direction introduces new challenges for the criminal justice system due to the persistence of unlawful distribution among persons who refuse to abide by the new law. Continuing unlawful distribution is foreseeable, in part, because of stringent measures to reduce availability by targeting participants in the illegal market. Recognizing that the most heavy, frequent, users account for the majority of cannabis consumed—and are the group most likely to keep purchasing from dealers because of lower costs and easy access—the illegal market will continue to provide a substantial (albeit unknown) proportion of the total volume. The recent change in policy in Canada provides new opportunities for research to assess how legalization of cannabis affects its use and distribution patterns. The National Cannabis Survey (NCS), administered at three-month intervals, allows for multi-wave comparison of prevalence statistics and point of purchase information before and after legalization. Drawing on the NCS, this article examines the extent to which the primary supply source has changed across the provinces, controlling for other factors and consumer characteristics. Findings are interpreted with reference to studies of cannabis law reform in North America informing research and policy observers in these and other jurisdictions, undergoing or considering, similar reforms.

Retail availability and legal purchases of dried flower in Canada post-legalization

Article

May 2021
DRUG ALCOHOL DEPEN

Objective Retail availability of cannabis has the potential to influence demand for both legal and illegal cannabis. The aims of the study were to: 1) estimate the percentage of consumers who report purchasing dried flower legally; and 2) examine the association between purchasing dried flower legally and retail availability, where retail availability was represented as: a) Canadian province; b) ‘objective’ retail proximity; and c) self-reported retail proximity. Methods Data come from Canadian respondents in Wave 2 of the International Cannabis Policy Study (ICPS) conducted one year after non-medical cannabis legalization in September-October 2019. Respondents were 18+ years in Alberta/Quebec and 19+ years elsewhere and had purchased any dried flower in the past year (n = 2,506). Respondents were recruited through commercial online panels. Weighted binary logistic regression models examined likelihood of purchasing dried flower legally. Results Overall, 47.7% of past-year dried flower purchasers reported last purchasing dried flower legally, with variation across provinces (range = 40.5%-81.2%). Likelihood of purchasing dried flower legally was greater among those who lived closer to a legal retail store based on Euclidean distance (<3 km vs. > 10 km: AOR = 1.56, 95% CI: 1.20,2.02), and who had shorter self-reported travel time to a retail store (<5 min. vs. > 15 min.: AOR = 2.24, 95% CI: 1.56,3.21). Conclusion One year after legalization, retail availability was associated with last purchasing dried flower legally among past-year dried flower purchasers. To our knowledge, the current study is among the first to examine the legality of purchase source used for dried flower and retail availability of cannabis in Canada post-legalization.

Pareto Distributions in Online Casino Gambling: Sensitivity to Timeframe and Associations with Self Exclusion

Article

Apr 2021
ADDICT BEHAV

The Pareto effect (also known as the 80/20 rule) describes a skewed distribution of engagement that is observed for many products. In this study, we investigated Pareto estimates for online casino gambling, and tested their association with voluntary self-exclusion (VSE) as a marker of gambling harm, and examined their sensitivity to varying time windows. We used one year of betting data from the eCasino section of a provincially-run gambling website in British Columbia, Canada. The data contained 30,920 account holders who placed at least one bet on the platform from October 2014 to September 2015. The top 20% most engaged gamblers accounted for 92% (based on total number of bets) and 90% (based on net losses) of eCasino gambling activity over the year. The top 20% of online gamblers displayed higher levels of VSE enrolment than the remaining 80% (total bets: 13% vs 7%; net losses: 16% vs 6%, respectively). Pareto estimates increased with longer time windows, from one month to one year (total bets: 80% to 92%; net losses: 81% to 90%, respectively). This accumulation was driven by the relative loyalty of the most engaged gamblers, coupled with the influx of new and more transient gamblers on a month-to-month basis. These data strengthen links between concentrations of engagement with online products and measures of harm, but also highlight the dynamic nature of these estimates. One year estimates are preferable for estimating the degree of concentration.

The association between cannabis use and testicular function in men: A systematic review and meta‐analysis

Article

Nov 2020

Objective To evaluate the association between cannabis use and testicular function (as assessed through semen quality and serum hormone levels) in different populations. Evidence Review Systematic review and meta‐analysis of population‐based retrospective cohort studies. PRISMA guidelines were used for abstracting data and assessing data quality and validity. Data were pooled using a fixed‐effect or random‐effects model depending on the heterogeneity of studies included. Pooled risk ratio (RR) of having any sperm abnormality and Testosterone, FSH, and LH standardized mean differences among male cannabis users and non‐users, and meta‐regression analysis according to age, and year of publication. Results Nine studies were evaluted which included 4014 men with semen data and 4787 with hormonal data. Overall among 1158 cannabis users, 44.9% had impaired semen parameters. Compared to 24.5% of the 2856 nonusers. The relative risk among cannabis users for any abnormal semen parameter was 1.159 (95%CI: 0.840; 1.599, p=0.369). The standardized mean difference between users and non‐users testosterone levels was ‐0.139 (95%CI: ‐0.413; 0.134, p= 0.318). For FSH, the standardized mean difference estimate was ‐0.142 (95%CI: ‐0.243; ‐0.0425, p=0.005), while for LH the standardized mean difference estimate was ‐0.318 (95%CI: ‐0.810‐0.175; p= 0.206). Conclusions The current evidence does not suggest clinically significant associations between cannabis use and testicular function. However, we cannot exclude an effect of cannabis due to the limited and heterogeneous studies. Additional, well‐designed studies will be needed to define the association between cannabis use and the male reproductive system.

Quantity and frequency of cannabis use in relation to cannabis-use disorder and cannabis-related problems

Article

Sep 2020

Background: In almost all of the literature examining the relation between cannabis use and cannabis-related harms, researchers have neglected to include quantity measures of cannabis use. The study aims to assess whether cannabis: (1) quantity predicts harms; and (2) quantity might interact with other key variables (age, gender, and frequency of use) vis-à-vis the outcomes. Method: Using the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III), the current study (n = 36,309; n = 3,339 past-year cannabis users) employed a logistic-regression approach to assess the cross-sectional relations between the continuous variables of cannabis-use quantity and frequency and two Alcohol Use Disorder and Associated Disabilities Interview Schedule-5 (AUDADIS-5) DSM-5-based outcomes: past-year cannabis-use disorder (CUD) and past-year cannabis-related problems (CRP). Results: In the CUD model, the key variables log quantity [OR = 1.98 (95 % CI, 1.64;2.39), p < 0.001], log frequency [OR = 1.78 (95 % CI, 1.62;1.96), p < 0.001] and the log-quantity-by-log-frequency interaction [OR = 0.83 (95 % CI, 0.75;0.93), p = 0.002] were statistically significant. The final CRP model included the following main predictors: log quantity [OR = 2.13 (95 % CI, 1.70;2.66), p = <0.001], log frequency [OR = 1.50 (95 % CI, 1.36;1.65), p = <0.001], and a log-quantity-by-log-frequency interaction [OR = 0.82 (95 % CI, 0.73;0.93), p = 0.002]. Conclusions: The quantity-by-frequency interactions in both models showed that the relative effect of quantity on cannabis-use disorders and cannabis-related problems decreased as frequency increased, and vice versa.

The Importance of Psychology for Shaping Legal Cannabis Regulation

Article

Full-text available

May 2020

Different patterns of cannabis use can be traced directly back to different interactions between 2 types of variables: pharmacological and environmental. As legal cannabis expands in the U.S. and around the world, state and national regulatory agencies are gaining control over these variables. Specifically, regulatory agencies are increasingly capable of altering (a) the pharmacological properties of cannabis products and (b) the way these products are distributed to the population. Consequently, cannabis regulatory agencies are in a unique position to use evidence from psychological science to alter cannabis consumption patterns in ways that mitigate potential harm to public health. However, most state-level legal cannabis regulatory systems in the U.S. are not yet evidence-based or public health-oriented. This applied review and commentary draws on evidence from the psychological science literature to help regulators better understand the types of behaviors they must address and guide empirically supported regulation of THC-laden cannabis, whether used putatively for medical or recreational reasons. This review is organized into 3 parts that correspond to the 3 primary agents within the cannabis regulation ecosystem: (a) the cannabis consumer, (b) the cannabis industry, and (c) the cannabis regulatory agency. Within this structure, the review addresses critical psychological variables that drive cannabis consumer and industry behaviors and discusses how regulatory agencies can use this information to protect public health. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Prevalence and forms of cannabis use in legal vs. illegal recreational cannabis markets

Article

Jan 2020

Background: Recreational or 'non-medical cannabis' has been legalized in several US states, and was legalized federally in Canada in October 2018. There is little comparative data on product use across jurisdictions, particularly with respect to the types of cannabis products used, which differentially impact health. Methods: Data are from Wave 1 of the International Cannabis Policy Study, collected from Aug 27-Oct 7, 2018. Respondents (n = 27,024) aged 16-65 completed an online survey measuring patterns of cannabis use, quantities and routes of administration. Respondents were recruited from Canada (n = 9976) and US states that had (n = 7362) and had not (n = 9686) legalized non-medical cannabis ('legal' and 'illegal' states, respectively). Results: Prevalence of at least daily, weekly, and monthly cannabis use were significantly higher in US 'legal' states (11.3%, 18.2%, 25.0%, respectively) than US 'illegal' states (7.4%, 11.6%, 16.8%, respectively; p<0.001) and Canada (8.9%, 14.1%, 19.0%, respectively; p ≤ 0.01). Dried herb was the dominant form of cannabis reported by past 12-month users across all jurisdictions (77.7%-80.8%). Although the amount of dried herb used per year did not differ by jurisdiction (range: 210.3-229.4 g), those in US 'legal' states were significantly more likely to use dried herb daily or weekly than were those in 'illegal' states and Canada (p<0.001). Use of cannabis concentrates, vaped oils, edibles, and drinks was more prevalent among US 'legal' states than 'illegal' states and Canada (p ≤ 0.001). Vaping dried herb was more common in both legal and illegal US jurisdictions than in Canada (p<0.05), whereas Canadians were more likely to smoke dried herb with tobacco (p<0.001). Conclusion: The prevalence of cannabis use-and use of products such as cannabis concentrates, edibles and drinks-was higher in US states that had legalized cannabis. Additional longitudinal research is required to determine whether these differences reflect causal effects of legalization or pre-existing secular trends.

Cannabis Countdown: Estimating the Size of Illegal Markets and Lost Tax Revenue Post-Legalization

Article

Full-text available

Jan 2018

Anatomy of a Joint: Comparing Self-Reported and Actual Dose of Cannabis and Tobacco in a Joint, and How These Are Influenced by Controlled Acute Administration

Article

Full-text available

Aug 2017

Introduction: Major gaps exist in the measurement of cannabis exposure. The accuracy of self-reported cannabis and tobacco dose per joint is poorly characterized and has never been investigated following acute cannabis/tobacco exposure. Using an innovative “Roll a Joint” paradigm, this study aims to (1) compare estimated and actual dose of cannabis and tobacco per joint at baseline and (2) examine the acute effects of cannabis and/or tobacco on estimated and actual dose. Materials and Methods: We investigated this by using a randomized, double-blind, placebo-controlled crossover 2 (active cannabis, placebo cannabis)×2 (active tobacco, placebo tobacco) design in a laboratory setting. Participants were 24 recreational cousers of cannabis and tobacco. At baseline, they were asked to measure out the amount of cannabis and tobacco they would put in an average joint for themselves (dose per joint). Then, on each of four drug administration sessions, participants were again asked to do this for a joint they would want to smoke “right now.” Self-reported and actual amount was recorded (g). Results: At baseline, the estimated amount of cannabis per joint (0.28±0.23 g) was double the actual amount (0.14±0.12 g) (p=0.003, d=0.723). No difference emerged between estimated (0.43±0.25 g) and actual (0.35±0.15 g) (p=0.125) amount of tobacco per joint. Compared to placebo, active cannabis reduced the actual dose of both cannabis (p=0.035) and tobacco (p<0.001) they put in a joint. Participants accurately estimated this reduction for tobacco (p=0.014), but not for cannabis (p=0.680). Conclusions: Self-reported dose per joint is accurate for tobacco but dramatically overestimates cannabis exposure and therefore should be viewed with caution. Cannabis administration reduced the amount of cannabis and tobacco added to joints, suggesting a reduction in dose during a smoking session. The “Roll A Joint” paradigm should be implemented for better accuracy in assessing dose per joint.

Evidence for the effectiveness of minimum pricing of alcohol: A systematic review and assessment using the Bradford Hill criteria for causality

Article

Full-text available

May 2017

Objectives To assess the evidence for price-based alcohol policy interventions to determine whether minimum unit pricing (MUP) is likely to be effective. Design Systematic review and assessment of studies according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, against the Bradford Hill criteria for causality. Three electronic databases were searched from inception to February 2017. Additional articles were found through hand searching and grey literature searches. Criteria for selecting studies We included any study design that reported on the effect of price-based interventions on alcohol consumption or alcohol-related morbidity, mortality and wider harms. Studies reporting on the effects of taxation or affordability and studies that only investigated price elasticity of demand were beyond the scope of this review. Studies with any conflict of interest were excluded. All studies were appraised for methodological quality. Results Of 517 studies assessed, 33 studies were included: 26 peer-reviewed research studies and seven from the grey literature. All nine of the Bradford Hill criteria were met, although different types of study satisfied different criteria. For example, modelling studies complied with the consistency and specificity criteria, time series analyses demonstrated the temporality and experiment criteria, and the analogy criterion was fulfilled by comparing the findings with the wider literature on taxation and affordability. Conclusions Overall, the Bradford Hill criteria for causality were satisfied. There was very little evidence that minimum alcohol prices are not associated with consumption or subsequent harms. However the overall quality of the evidence was variable, a large proportion of the evidence base has been produced by a small number of research teams, and the quantitative uncertainty in many estimates or forecasts is often poorly communicated outside the academic literature. Nonetheless, price-based alcohol policy interventions such as MUP are likely to reduce alcohol consumption, alcohol-related morbidity and mortality.

Adverse Health Effects of Marijuana Use

Article

Full-text available

Jun 2014
NEW ENGL J MED

As marijuana use becomes legal in some states, the dominant public opinion is that marijuana is a harmless source of mood alteration. Although the harms associated with marijuana use have not been well studied, enough information is available to cause concern.

Statistics on Cannabis Users Skew Perceptions of Cannabis Use

Article

Full-text available

Nov 2013

Collecting information about the prevalence of cannabis use is necessary but not sufficient for understanding the size, dynamics, and outcomes associated with cannabis markets. This paper uses two data sets describing cannabis consumption in the United States and Europe to highlight (1) differences in inferences about sub-populations based on the measure used to quantify cannabis-related activity; (2) how different measures of cannabis-related activity can be used to more accurately describe trends in cannabis usage over time; and (3) the correlation between frequency of use in the past-month and average grams consumed per use-day. Key findings: focusing on days of use instead of prevalence shows substantially greater increases in U.S. cannabis use in recent years; however, the recent increase is mostly among adults, not youth. Relatively more rapid growth in use days also occurred among the college-educated and Hispanics. Further, data from a survey conducted in seven European countries show a strong positive correlation between frequency of use and quantity consumed per day of use, suggesting consumption is even more skewed toward the minority of heavy users than is suggested by days-of-use calculations.

The Raising of Minimum Alcohol Prices in Saskatchewan, Canada: Impacts on Consumption and Implications for Public Health

Article

Full-text available

Oct 2012
AM J PUBLIC HEALTH

Objectives: We report impacts on alcohol consumption following new and increased minimum alcohol prices in Saskatchewan, Canada. Methods: We conducted autoregressive integrated moving average time series analyses of alcohol sales and price data from the Saskatchewan government alcohol monopoly for 26 periods before and 26 periods after the intervention. Results: A 10% increase in minimum prices significantly reduced consumption of beer by 10.06%, spirits by 5.87%, wine by 4.58%, and all beverages combined by 8.43%. Consumption of coolers decreased significantly by 13.2%, cocktails by 21.3%, and liqueurs by 5.3%. There were larger effects for purely off-premise sales (e.g., liquor stores) than for primarily on-premise sales (e.g., bars, restaurants). Consumption of higher strength beer and wine declined the most. A 10% increase in minimum price was associated with a 22.0% decrease in consumption of higher strength beer (> 6.5% alcohol/volume) versus 8.17% for lower strength beers. The neighboring province of Alberta showed no change in per capita alcohol consumption before and after the intervention. Conclusions: Minimum pricing is a promising strategy for reducing the public health burden associated with hazardous alcohol consumption. Pricing to reflect percentage alcohol content of drinks can shift consumption toward lower alcohol content beverage types.

Determining the best population-level alcohol consumption model and its impact on estimates of alcohol-attributable harms

Article

Full-text available

Apr 2012

The goals of our study are to determine the most appropriate model for alcohol consumption as an exposure for burden of disease, to analyze the effect of the chosen alcohol consumption distribution on the estimation of the alcohol Population- Attributable Fractions (PAFs), and to characterize the chosen alcohol consumption distribution by exploring if there is a global relationship within the distribution. To identify the best model, the Log-Normal, Gamma, and Weibull prevalence distributions were examined using data from 41 surveys from Gender, Alcohol and Culture: An International Study (GENACIS) and from the European Comparative Alcohol Study. To assess the effect of these distributions on the estimated alcohol PAFs, we calculated the alcohol PAF for diabetes, breast cancer, and pancreatitis using the three above-named distributions and using the more traditional approach based on categories. The relationship between the mean and the standard deviation from the Gamma distribution was estimated using data from 851 datasets for 66 countries from GENACIS and from the STEPwise approach to Surveillance from the World Health Organization. The Log-Normal distribution provided a poor fit for the survey data, with Gamma and Weibull distributions providing better fits. Additionally, our analyses showed that there were no marked differences for the alcohol PAF estimates based on the Gamma or Weibull distributions compared to PAFs based on categorical alcohol consumption estimates. The standard deviation of the alcohol distribution was highly dependent on the mean, with a unit increase in alcohol consumption associated with a unit increase in the mean of 1.258 (95% CI: 1.223 to 1.293) (R2 = 0.9207) for women and 1.171 (95% CI: 1.144 to 1.197) (R2 = 0. 9474) for men. Although the Gamma distribution and the Weibull distribution provided similar results, the Gamma distribution is recommended to model alcohol consumption from population surveys due to its fit, flexibility, and the ease with which it can be modified. The results showed that a large degree of variance of the standard deviation of the alcohol consumption Gamma distribution was explained by the mean alcohol consumption, allowing for alcohol consumption to be modeled through a Gamma distribution using only average consumption.

The 'grass ceiling': Limitations in the literature hinder our understanding of cannabis use and its consequences

Article

Full-text available

Feb 2011
ADDICTION

To illustrate how limitations in the cannabis literature undermine our ability to understand cannabis-related harms and problems experienced by users and identify users at increased risk of experiencing adverse outcomes of use. Limitations have been organized into three overarching themes. The first relates to the classification systems employed by researchers to categorize cannabis users, their cannabis use and the assumptions on which these systems are based. The second theme encompasses methodological and reporting issues, including differences between studies, inadequate statistical control of potential confounders, the under-reporting of effect sizes and the lack of consideration of clinical significance. The final theme covers differing approaches to studying cannabis use, including recruitment methods. Limitations related to the nature of the data collected by researchers are discussed throughout, with a focus on how they affect our understanding of cannabis use and users. These limitations must be addressed to facilitate the development of effective and appropriately targeted evidence-based public health campaigns, treatment programmes and preventative, early intervention and harm minimization strategies, and to inform cannabis-related policy and legislation.

The THC Content of Cannabis in Australia: Evidence and Implications

Article

Full-text available

Nov 2000

To examine evidence on three claims that: 1) the THC content of Australian cannabis plants has increased up to 30 times; 2) problems experienced by cannabis users have increased in Australia in recent years; and 3) an increase in THC content is the most likely explanation of any increase in cannabis-related problems. These claims were assessed by examining data: 1) on THC potency in Australia, the United States and New Zealand; 2) on cannabis-related problems; and 3) from the 1998 National Drug Strategy Household Survey on patterns of cannabis use. 1) Published data do not show a 30-fold increase in THC potency of cannabis but show a more modest increase in the US. 2) There is suggestive evidence of an increase in cannabis-related problems among people seeking treatment for alcohol and drug problems, juvenile offenders and young adults with psychosis. 3) There are two other more plausible explanations for these reportedly higher rates of cannabis-related problems among adolescents and young adults: (i) more potent forms of cannabis ('heads') are more widely used; and (ii) cannabis users are initiating cannabis at an earlier age, thereby increasing the prevalence of harmful patterns of use. There has probably been a modest increase in the THC content of cannabis, but changing patterns of cannabis use have probably made a larger contribution to any increase in rates of cannabis-related problems among young Australian adults. Better data on the THC content of cannabis, the extent of cannabis-related problems and the ability of users to titrate the dose of cannabis would contribute to more informed debate.

How high: Quantity as a predictor of cannabis-related problems

Article

Full-text available

Feb 2008

Research on cannabis use has emphasized frequency as a predictor of problems. Studies of other drugs reveal that frequency relates to psychological and physiological outcomes, but quantity also plays an important role. In the study of cannabis, quantity has been difficult to assess due to the wide range of products and means of consumption. The present study introduces three new measures of quantity, and examines their contribution to cannabis-related problems. Over 5,900 adults using cannabis once or more per month completed an internet survey that inquired about use, dependence, social problems and respiratory health. In addition to detailing their frequency of cannabis use, participants also reported three measures of quantity: number of quarter ounces consumed per month, usual intensity of intoxication, and maximum intensity of intoxication. Frequency of use, monthly consumption, and levels of intoxication predicted respiratory symptoms, social problems and dependence. What is more, each measure of quantity accounted for significant variance in outcomes after controlling for the effects of frequency. These findings indicate that quantity is an important predictor of cannabis-related outcomes, and that the three quantity measures convey useful information about use.

Price and product variation in Washington's recreational cannabis market

Article

Sep 2019
INT J DRUG POLICY

Steven Davenport

Background: Ten U.S. states, Canada, and Uruguay have passed laws to legalize the production and sale of cannabis for non-medical purposes. Available research has documented rapidly falling prices and changing product mixes, but many details are not well understood: particularly, the popularity, prices, and product characteristics of different cannabis edibles and extract-based products - each offering different ways to consume cannabis, with unclear health consequences. Methods: This paper analyzes data from Washington's recreational cannabis market, which has recorded over 110 million retail item-transactions from July 2014 to October 2017. Previous research on price and product trends has focused mostly on herbal cannabis, which accounts for the majority, but a decreasing share, of sales. This paper applies advanced text-analytic methods to provide new insights, including (A) estimating potency data for edibles and (B) identifying extract sub-types. Patterns and trends are described, across product types, regarding THC and CBD profiles and price per THC. Results: Extracts accounted for 28.5% of sales in October 2017. Of extracts categorized to subtype, nearly half were identified as "dabs", and another half "cartridges". In October 2017, price per 10 mg THC was roughly $3 among edibles, 70 cents among extract cartridges, and 30-40 cents for other flower and other extracts; solid concentrates offered the lowest priced THC among extract products. Price declines continue but have slowed. High-CBD chemovars are becoming more common, but still are almost non-existent in flower marijuana and rare (1% of sales) among extract products. Conclusion: As Washington's recreational cannabis market has developed over three and a half years, trends identified in that market may serve as an early indication of potential issues in other states. Legislators and regulators in other jurisdictions with commercial non-medical cannabis markets may wish to establish policies responsive to these trends in product popularity, price, and potency.

Smoking, Vaping, and Use of Edibles and Other Forms of Marijuana Among U.S. Adults

Article

Aug 2018

Lower-Risk Cannabis Use Guidelines: A Comprehensive Update of Evidence and Recommendations

Article

Aug 2017

Background: Cannabis use is common in North America, especially among young people, and is associated with a risk of various acute and chronic adverse health outcomes. Cannabis control regimes are evolving, for example toward a national legalization policy in Canada, with the aim to improve public health, and thus require evidence-based interventions. As cannabis-related health outcomes may be influenced by behaviors that are modifiable by the user, evidence-based Lower-Risk Cannabis Use Guidelines (LRCUG)-akin to similar guidelines in other health fields-offer a valuable, targeted prevention tool to improve public health outcomes. Objectives: To systematically review, update, and quality-grade evidence on behavioral factors determining adverse health outcomes from cannabis that may be modifiable by the user, and translate this evidence into revised LRCUG as a public health intervention tool based on an expert consensus process. Search methods: We used pertinent medical search terms and structured search strategies, to search MEDLINE, EMBASE, PsycINFO, Cochrane Library databases, and reference lists primarily for systematic reviews and meta-analyses, and additional evidence on modifiable risk factors for adverse health outcomes from cannabis use. Selection criteria: We included studies if they focused on potentially modifiable behavior-based factors for risks or harms for health from cannabis use, and excluded studies if cannabis use was assessed for therapeutic purposes. Data collection and analysis: We screened the titles and abstracts of all studies identified by the search strategy and assessed the full texts of all potentially eligible studies for inclusion; 2 of the authors independently extracted the data of all studies included in this review. We created Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow-charts for each of the topical searches. Subsequently, we summarized the evidence by behavioral factor topic, quality-graded it by following standard (Grading of Recommendations Assessment, Development, and Evaluation; GRADE) criteria, and translated it into the LRCUG recommendations by the author expert collective on the basis of an iterative consensus process. Main results: For most recommendations, there was at least "substantial" (i.e., good-quality) evidence. We developed 10 major recommendations for lower-risk use: (1) the most effective way to avoid cannabis use-related health risks is abstinence, (2) avoid early age initiation of cannabis use (i.e., definitively before the age of 16 years), (3) choose low-potency tetrahydrocannabinol (THC) or balanced THC-to-cannabidiol (CBD)-ratio cannabis products, (4) abstain from using synthetic cannabinoids, (5) avoid combusted cannabis inhalation and give preference to nonsmoking use methods, (6) avoid deep or other risky inhalation practices, (7) avoid high-frequency (e.g., daily or near-daily) cannabis use, (8) abstain from cannabis-impaired driving, (9) populations at higher risk for cannabis use-related health problems should avoid use altogether, and (10) avoid combining previously mentioned risk behaviors (e.g., early initiation and high-frequency use). Authors' conclusions: Evidence indicates that a substantial extent of the risk of adverse health outcomes from cannabis use may be reduced by informed behavioral choices among users. The evidence-based LRCUG serve as a population-level education and intervention tool to inform such user choices toward improved public health outcomes. However, the LRCUG ought to be systematically communicated and supported by key regulation measures (e.g., cannabis product labeling, content regulation) to be effective. All of these measures are concretely possible under emerging legalization regimes, and should be actively implemented by regulatory authorities. The population-level impact of the LRCUG toward reducing cannabis use-related health risks should be evaluated. Public health implications. Cannabis control regimes are evolving, including legalization in North America, with uncertain impacts on public health. Evidence-based LRCUG offer a potentially valuable population-level tool to reduce the risk of adverse health outcomes from cannabis use among (especially young) users in legalization contexts, and hence to contribute to improved public health outcomes.

The Historical Roots of Ledermann's Theory of the Distribution of Alcohol Consumption

Article

Mar 2006

Ole-Jørgen Skog

Ledermann's theory of the distribution of alcohol consumption in populations, which was published in 1956, is reviewed and discussed. The theory is based on some rather peculiar hypotheses, and an attempt is made to make sense of these hypotheses in light of Ledermann's research prior to 1956. The central question posed in this paper is what made Ledermann believe that strong regularities were to be expected. Furthermore, Ledermann's empirical data are scrutinized, and it is concluded that most of the data were inadequate for testing a distribution model which should be applied to the general population in different drinking cultures.

The Standard Joint Unit

Article

May 2017

Objective: Reliable data on cannabis quantities is required to improve assessment of cannabis consumption for epidemiological analysis and clinical assessment, consequently a Standard Joint Unit (SJU) based on quantity of 9-Tetrahydrocannabinol (9-THC) has been established. Methodology: Naturalistic study of a convenience sample recruited from February 2015-June 2016 in universities, leisure spaces, mental health services and cannabis clubs in Barcelona. Adults, reporting cannabis use in the last 60 days, without cognitive impairment or language barriers, answered a questionnaire on cannabis use and were asked to donate a joint to further determine their 9-THC and Cannabidiol (CBD) content. Results: 492 participants donated 315 valid joints. Donators were on average 29 years old, mostly men (77%), single (75%), with at least secondary studies (73%) and in active employment (63%). Marijuana joints (N=232) contained a median of 6.56mg of 9-THC (Interquartile range-IQR=10,22) and 0.02mg of CBD (IQR=0.02); hashish joints (N=83) a median of 7.94mg of 9-THC (IQR=10,61) and 3.24mg of CBD (IQR=3.21). Participants rolled 4 joints per gram of cannabis and paid 5€ per gram (median values). Conclusion: Consistent 9-THC-content in joints lead to a SJU of 7mg of 9-THC, the integer number closest to the median values shared by both cannabis types. Independently if marijuana or hashish, 1 SJU = 1 joint = 0.25 g of cannabis = 7 mg of 9-THC. For CBD, only hashish SJU contained relevant levels. Similarly to the Standard Drink Unit for alcohol, the SJU is useful for clinical, epidemiological and research purposes.

Definitions of Risky and Problematic Cannabis Use: A Systematic Review

Article

Aug 2016

Unlabelled: Although cannabis is widely used, it remains unclear which consumption patterns are more likely to produce future consequences (risky/hazardous use) or current damage (problematic/harmful use). This unresolved issue contributes to cannabis public health implications. In order to facilitate further consensus, this review analyzes previously used definitions in the literature. Methods: This systematic review was performed following the PRISMA guidelines. Articles published before October 2015 in the Medline, Scopus-Elsevier, ISI-Web of Knowledge and Cochrane databases and fulfilling a-priori decided criteria were retrieved. Definitions in preselected websites of national and international organizations addressing drug problems were also included. Results: Definitions identified in articles (n = 46) and official websites (n = 3) widely varied from each other. Weekly cannabis use was mostly considered risky. Problematic cannabis use was mostly described with the Cannabis Abuse and Screening Test. Evidence-based definitions as well as information on quantities consumed, time-frames and special considerations for risky groups were very limited. Conclusions: Working on official definitions is highly necessary as criteria used remain incomplete, leading to increased confusion in the field. Recommendations to improve existing definitions are given.

Bayesian inference for the distribution of grams of marijuana in a joint

Article

Jun 2016

Background: The average amount of marijuana in a joint is unknown, yet this figure is a critical quantity for creating credible measures of marijuana consumption. It is essential for projecting tax revenues post-legalization, estimating the size of illicit marijuana markets, and learning about how much marijuana users are consuming in order to understand health and behavioral consequences. Methods: Arrestee Drug Abuse Monitoring data collected between 2000 and 2010 contain relevant information on 10,628 marijuana transactions, joints and loose marijuana purchases, including the city in which the purchase occurred and the price paid for the marijuana. Using the Brown-Silverman drug pricing model to link marijuana price and weight, we are able to infer the distribution of grams of marijuana in a joint and provide a Bayesian posterior distribution for the mean weight of marijuana in a joint. Results: We estimate that the mean weight of marijuana in a joint is 0.32g (95% Bayesian posterior interval: 0.30-0.35). Conclusions: Our estimate of the mean weight of marijuana in a joint is lower than figures commonly used to make estimates of marijuana consumption. These estimates can be incorporated into drug policy discussions to produce better understanding about illicit marijuana markets, the size of potential legalized marijuana markets, and health and behavior outcomes.

Governmental standard drink definitions and low-risk alcohol consumption guidelines in 37 countries

Article

Apr 2016
ADDICTION

Background and aims: One of the challenges of international alcohol research and policy is the variability in and lack of knowledge of how governments in different nations define a standard drink and low-risk drinking. This study gathered such information from governmental agencies in 37 countries. Methods: A pool of 75 countries that might have definitions was created using World Health Organization (WHO) information and the authors' own judgement. Structured internet searches of relevant terms for each country were supplemented by efforts to contact government agencies directly and to consult with alcohol experts in the country. Results: Most of the 75 national governments examined were not identified as having adopted a standard drink definition. Among the 37 that were so identified, the modal standard drink size was 10 g pure ethanol, but variation was wide (8-20 g). Significant variability was also evident for low-risk drinking guidelines, ranging from 10-42 g per day for women and 10-56 g per day for men to 98-140 g per week for women and 150-280 g per week for men. Conclusions: Researchers working and communicating across national boundaries should be sensitive to the substantial variability in 'standard' drink definitions and low-risk drinking guidelines. The potential impact of guidelines, both in general and in specific national cases, remains an important question for public health research.

Alcohol and the so-called prevention paradox: how does it look today?

Article

Feb 2006

Ole-Jørgen Skog

Problems with the Identification of 'Problematic' Cannabis Use: Examining the Issues of Frequency, Quantity, and Drug Use Environment

Article

Aug 2014

Considerable recent attention has focused on how harmful or problematic cannabis use is defined and understood in the literature and put to use in clinical practice. The aim of the current study is to review conceptual and measurement shortcomings in the identification of problematic cannabis use, drawing on the WHO ASSIST instrument for specific examples. Three issues with the current approach are debated and discussed: (1) the identification of problematic cannabis use disproportionately relies on measures of the frequency of cannabis consumption rather than the harms experienced; (2) the quantity consumed on a typical day is not considered when assessing problematic use, and (3) screening tools for problematic use employ a 'one-size-fits-all approach' and fail to reflect on the drug use context (networks and environment). Our commentary tackles each issue, with a review of relevant literature coupled with analyses of two Canadian data sources - a representative sample of the Canadian adult population and a smaller sample of adult, regular, long-term cannabis users from four Canadian cities - to further articulate each point. This article concludes with a discussion of appropriate treatment interventions and approaches to reduce cannabis-related harms, and offers suggested changes to improve the measurement of problematic cannabis use. © 2014 S. Karger AG, Basel.

A 'standard joint'? The role of quantity in predicting cannabis-related problems

Article

Feb 2012

The 'standard drink' concept is widely used as a standardized measure of alcohol consumption. There is no equivalent measure of cannabis con-sumption, perhaps due to challenges such as varied joint size, tetrahydrocannabinol content, and means of delivery. This study introduces a new measure of cannabis quantity and examines whether it predicts cannabis-related social problems with and without controlling for frequency of use. Cannabis-related problems, measured by the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST), were predicted from cannabis use frequency (days in past month) and quantity (one joint ¼ 0.5 g, five bong or pipe hits, 10 puffs), controlling for age and gender. The sample consisted of 665 participants aged 15–67 (mean ¼ 28.2, SD ¼ 11.8) from the British Columbia Alcohol and Other Drug Monitoring Project, High Risk Group Surveys, 2008 to 2009. Cannabis use frequency and quantity were positively associated with cannabis-related prob-lems. Individuals who consumed cannabis daily and consumed more than one joint per day were at the greatest risk of problems. Controlling for frequency, the effect of quantity remained significant for failure to do what is expected due to cannabis use. This study suggests that quantity, above and beyond frequency, is an important predictor of cannabis problems. We discuss the potential usefulness and validity of this new measure in harm reduction.

The collectivity of changes in alcohol consumption revisited

Article

Feb 2014
ADDICTION

Within-country temporal changes in alcohol consumption in the USA, Finland, and Norway were examined to assess 1) whether a change in mean alcohol consumption is accompanied by a change in the prevalence of heavy drinkers, 2) whether this mean change reflects a collective displacement in the whole distribution of consumption, and 3) whether collective displacement is found for both an upward and a downward shift in mean consumption. We applied repeated cross-sectional survey data on distribution measures for estimated annual alcohol consumption from national population sample surveys covering 30 to 40 years periods in two countries with increasing trends in mean consumption (Finland and Norway) and one country with decreasing trends (the USA). There was a strong positive association (P <0.001) between changes in mean consumption and changes in the prevalence of heavy drinkers in all three countries. Moreover, a change in mean consumption was accompanied by a consumption change in the same direction in all consumer categories in all three countries, i.e. a collective displacement. The regression coefficients were around 1. Drinkers at all levels of consumption appear to move in concert, both up and down the consumption scale in Finland, Norway, and the USA, as predicted by Skog's theory of the collectivity of drinking cultures.

The Distribution of Alcohol Consumption and the Prevention Paradox in Brazil

Article

Oct 2011
ADDICTION

Aims To examine the proportion of self-reported alcohol consumed by different gender and age groups in Brazil over the past year, and to examine whether the ‘prevention paradox’ applies to Brazilian data on alcohol-related problems. Design A multi-stage cluster sample, representative of the Brazilian household population. Setting This study was conducted in Brazil between November 2005 and April 2006. Participants Respondents were aged ≥ 14 years (n = 3007). Measurements Measures included past year estimates of (i) number of standard drinks, (ii) frequency of binge drinking, and (iii) alcohol-related problems. Findings The survey response rate was 66.4%. The top 2.5% of the drinkers by volume consume 14.9%, the top 5% consume 27.4% and the top 10% consume 44.2% of all alcohol consumed in Brazil. Men consume 77.8% of the total alcohol, and 18–29-year-olds consume 40.3%. Individuals below risky drinking guidelines for weekly volumetric intake account for 49–50% of all problem drinkers and 45–47% of all problem types reported. Individuals who do not binge or who binge infrequently (1–3 times/year) account for 50–51% of all problem drinkers and 45–46% of all reported problem types. Most binge drinkers are low-volume drinkers. Conclusions Consistent with the prevention paradox literature, most drinking problems in Brazil are associated with low or moderate drinking. Binge drinking accounts more clearly for the distribution of alcohol problems than total volume consumed.

Understanding standard drinks and drinking guidelines

Article

Nov 2011
DRUG ALCOHOL REV

For consumers to follow drinking guidelines and limit their risk of negative consequences they need to track their ethanol consumption. This paper reviews published research on the ability of consumers to utilise information about the alcohol content of beverages when expressed in different forms, for example in standard drinks or units versus percentage alcohol content. A review of the literature on standard drink definitions and consumer understanding of these, actual drink pouring, use of standard drinks in guidelines and consumer understanding and use of these. Standard drink definitions vary across countries and typically contain less alcohol than actual drinks. Drinkers have difficulty defining and pouring standard drinks with over-pouring being the norm such that intake volume is typically underestimated. Drinkers have difficulty using percentage alcohol by volume and pour size information in calculating intake but can effectively utilise standard drink labelling to track intake. Standard drink labelling is an effective but little used strategy for enabling drinkers to track their alcohol intake and potentially conform to safe or low-risk drinking guidelines.

Is there an epidemiological paradox for illicit drugs?

Article

Feb 2011
ADDICTION

Sven Andréasson

Global Burden of Disease and Injury and Economic Cost Attributable to Alcohol Use and Alcohol-Use Disorders

Article

Jul 2009
LANCET

Alcohol consumption has been identified as an important risk factor for chronic disease and injury. In the first paper in this Series, we quantify the burden of mortality and disease attributable to alcohol, both globally and for ten large countries. We assess alcohol exposure and prevalence of alcohol-use disorders on the basis of reviews of published work. After identification of other major disease categories causally linked to alcohol, we estimate attributable fractions by sex, age, and WHO region. Additionally, we compare social costs of alcohol in selected countries. The net effect of alcohol consumption on health is detrimental, with an estimated 3.8% of all global deaths and 4.6% of global disability-adjusted life-years attributable to alcohol. Disease burden is closely related to average volume of alcohol consumption, and, for every unit of exposure, is strongest in poor people and in those who are marginalised from society. The costs associated with alcohol amount to more than 1% of the gross national product in high-income and middle-income countries, with the costs of social harm constituting a major proportion in addition to health costs. Overall, we conclude that alcohol consumption is one of the major avoidable risk factors, and actions to reduce burden and costs associated with alcohol should be urgently increased.

Alcohol Consumption and the Preventive Paradox

Article

Jul 1986

Norman Kreitman

Drinkers in the general population who exceed the 'safe limits' advocated by various experts are undoubtedly at high risk of alcohol-related harm, yet they contribute only a minority to the total numbers of alcohol casualties. This relationship, the so-called 'preventive paradox' was explored in some detail using different criteria for 'safe limits' for total consumption, for frequency of drinking and for maximal daily consumption: two population surveys and a study of special groups noted for high intake were used. The results were in general mutually corroborative, even when different criteria for harm were employed. Certain methodological problems attendant on such analyses were explored. Finally it was shown that the gains from the universal adoption of the conventional 'safe limits' within a population would be matched by an across-the-board per capita reduction to about 70% of current intake. The implication was briefly reviewed.

The Collectivity of Drinking Cultures: A Theory of the Distribution of Alcohol Consumption

Article

Apr 1985

Ole-Jørgen Skog

In this paper it is argued that Ledermann's so-called single-distribution theory is not based on substantial hypotheses about human drinking behaviour, and that it therefore fails to explain anything. An alternative theory of the distribution of alcohol consumption is outlined. The theory is founded on two basic hypotheses about human drinking behaviour. The theory is tested against survey data from different countries, and it is concluded that a strong collective components exists in human drinking habits. As a main rule, the population tends to move in concert up and down the scale of consumption.

Who drinks most of the alcohol in the U.S.? The policy implications

Article

Feb 1999

The concentration of alcohol consumption in the U.S. among the heaviest drinkers is analyzed with data from two recent probability samples of the adult population. Pooled data from four national telephone surveys (N = 7,049; 4,784 drinkers) with uniform methodology are used for the primary analysis, and data from an in-person national household survey (N = 2,058; 1,308 drinkers) are used for confirmatory analysis. Each survey systematically measured self-reported alcohol consumption during the prior year using a "graduated frequencies" approach designed to capture drinking at a series of amount-per-day levels. The two studies produced very similar estimates: the top 2.5% of drinkers by volume account for 27% and 25% of the nation's total self-reported alcohol consumption in the telephone and in-person surveys, respectively; the top 5% account for 42% and 39%; and the top 20% of drinkers account for 89% and 87% in each survey, respectively. Men were overrepresented at the highest volumes, contributing about 76% of the country's total reported consumption. Similarly, young adults aged 18 to 29 are disproportionately represented in the heaviest drinking levels; constituting 27% of the population, they account for about 45% of overall adult drinking. The bulk of the alcohol reported drunk in the U.S. is consumed by a relatively small population of very heavy drinkers. Prevention policies implied by this concentration include strengthening of social norms discouraging heavy consumption, restricting marketing practices that target heavy drinkers, and implementing measures to reduce consumption by the heaviest drinkers.

Unravelling the Preventive Paradox for Acute Alcohol Problems

Article

Apr 1996

Kreitman's discussion of the preventive paradox in relation to the prevention of alcohol problems has had profound implications for alcohol policy and has generated considerable controversy [1]. It is argued here that although Kreitman should be credited with the important observation that alcohol-related harm is not confined to a few dependent drinkers, none the less an apparent paradox is not an ideal platform from which to recommend policy. Furthermore, Kreitman's own data and data from an Australian survey of drinking are used to demonstrate that a commonplace truth underlies his apparently paradoxical findings. It is shown that the preventive paradox disappears when consideration is given to the amount of alcohol consumed on either (i) the day of highest alcohol intake out of the last four, or (ii) the day on which acute alcohol-related harm occurred. Episodic heavy consumption by people whose average alcohol intake can be classified as 'low' or 'medium' risk contributes to the bulk of such experiences of harm. It is suggested that the importance of intoxication as a public health and safety issue has been neglected. This neglect is compounded when public education campaigns and prevention policy are only based on average rates of alcohol consumption. Advice regarding the low risk levels of consumption for different types of harm should form one component of a comprehensive harm reduction policy. Other elements of such a policy should include a variety of other measures of proven effectiveness in relation to reducing levels of intoxication and related problems.

Comments on Skog (2006): The prevention paradox always looked to me like a sleight of hand

Article

Mar 2006

Tim Stockwell

Cannabis legalization in Canada and comparison with US states. Oral presentation at: 2019 North American Cannabis Summit

Jan 2019

D Hammond
S Goodman
E Wadsworth

Hammond, D., Goodman, S., Wadsworth, E., 2019. Cannabis legalization in Canada and comparison with US states. Oral presentation at: 2019 North American Cannabis Summit;

Marijuana Equivalency in Portion and Dosage: an Assessment of Physical and Pharmacokinetic Relationships in Marijuana Production and Consumption in Colorado. Colorado Department of Revenue

Jan 2015

A Orens
M Light
J Rowberry
J Matsen
B Lewandowski

Orens, A., Light, M., Rowberry, J., Matsen, J., Lewandowski, B., 2015. Marijuana Equivalency in Portion and Dosage: an Assessment of Physical and Pharmacokinetic Relationships in Marijuana Production and Consumption in Colorado. Colorado Department of Revenue, Denver, CO (Accessed on 6.14.19). https://www.colorado. gov/pacific/sites/default/files/MED%20Equivalency_Final%2008102015.pdf.

Market Size and Demand for Marijuana in Colorado 2017 Market Update. Colorado Department of Revenue

Jan 2018

A Orens
M K Light
B Lewandowski
T Pickton

Orens, A., Light, M.K., Lewandowski, B., Pickton, T., 2018. Market Size and Demand for Marijuana in Colorado 2017 Market Update. Colorado Department of Revenue, Denver, CO (Accessed on 6.14.19). https://www.colorado.gov/pacific/sites/default/ files/MED%20Demand%20and%20Market%20%20Study%20%20082018.pdf.

Prince Edward Island Cannabis Management Corporation

Jan 2018

Prince Edward Island Cannabis Management Corporation, 2018. P.E.I. Cannabis. (Accessed on 5.22.19). https://peicannabiscorp.com/collections/cannabis/formspre-rolled.

National Cannabis Survey, First Quarter

Apr 2018

Statistics Canada, 2018a. National Cannabis Survey, First Quarter 2018. The Daily, April 18. Statistics Canada Catologue no. 11-001-X. (Accessed on 6.14.19). https:// www150.statcan.gc.ca/n1/en/daily-quotidien/180418/dq180418b-eng.pdf?st= itQg9iU0.

National Cannabis Survey, Third Quarter 2018. The Daily

Oct 2018

Statistics Canada, 2018c. National Cannabis Survey, Third Quarter 2018. The Daily, October 11. Statistics Canada Catologue no. 11-001-X. (Accessed on 6.14.19).

Who consumes most of the cannabis in Canada? Profiles of cannabis consumption by quantity

Abstract

No full-text available

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