Trends in marijuana and heavy alcohol use by cigarette smoking status among US adults: An analysis of the 2002-2019 NSDUH.

BACKGROUND: Polysubstance use is associated with adverse health outcomes, yet little research has measured changes in polysubstance use. We aimed to 1) estimate trends in marijuana and heavy alcohol use by cigarette smoking and demographic subgroups, and 2) examine patient factors associated with concurrent use among adults who were smoking. METHODS: We conducted a repeated cross-sectional analysis of 687,225 non-institutionalized US adults ≥18 years from the 2002-2019 National Survey on Drug Use and Health. Participants were stratified into current, former, and never smoking groups. Main outcomes were prevalence of heavy alcohol use, marijuana use, and concurrent use of both substances. RESULTS: From 2002-2019, heavy alcohol use declined from 7.8 % to 6.4 %, marijuana use rose from 6.0 % to 11.8 %, and concurrent use of alcohol and marijuana remained stable. Among adults who were smoking from 2005 to 2019, higher education was associated with higher odds of heavy alcohol use, while older ages, female gender, non-White race/ethnicity, and government-provided health insurance were associated with lower odds. The odds of marijuana use decreased in females, older ages, and higher incomes while increasing in people with poorer health status, higher education, government-provided or no health insurance, and serious mental illness. Compared to White adults who were smoking, Black counterparts had higher odds of marijuana use (OR=1.23; 95 %CI: 1.15-1.29), while Hispanic (OR=0.68; 95 %CI: 0.63-0.72) and other racial/ethnic identities (OR=0.83; 95 %CI: 0.77-0.90) had lower odds. CONCLUSIONS: Our study suggests marijuana use might not be sensitive to changes in the use of tobacco and alcohol.

How have cannabis use and related indicators changed since legalization of cannabis for non-medical purposes? Results of the Canadian Cannabis Survey 2018-2022.

BACKGROUND: Cannabis use for non-medical purposes was legalized and regulated in Canada through the Cannabis Act in October 2018. This paper examined trends in use of cannabis for non-medical purposes and related indicators from pre- to post-legalization in Canada (2018-2022). METHODS: Data from 5 years of the Canadian Cannabis Survey, an annual web-based survey administered to Canadians 16 years of age or older, were used in the analysis (n2018=12,952; n2019=11,922; n2020=10,821; n2021=10,733; n2022=10,048). Cannabis measures include questions about use, types of products, sources, risk perceptions and beliefs, and exposure to public education campaigns and health warnings. Adjusted logistic regression models tested differences in outcomes over time. RESULTS: Past 12-month cannabis consumption increased among Canadians from 22 % in 2018 to 27 % in 2022 (AOR=1.41;99 % CI:1.28-1.54). Similarly, daily/almost daily (DAD) consumption increased from 5 % in 2018 to 7 % in 2022 (AOR=1.36;99 % CI:1.16-1.59). Consumption of dried flower, hash/kief, and concentrates/extracts (e.g., wax, shatter, budder) decreased since 2018, whereas consumption of edibles, beverages and vape pens/cartridges increased (p < 0.001). Legal purchasing increased from 4 % in 2018 to 69 % in 2022, while accessing cannabis through social and illegal sources decreased over time (p < 0.001). CONCLUSION: More Canadians are reporting cannabis consumption since legalization and regulation of cannabis for non-medical purposes, continuing a pre-existing trend despite an increase in awareness of the risks of consuming cannabis. Trends in product use indicate a transition from dried flower and concentrates/extracts towards consumption of cannabis foods, drinks and vape pens/cartridges. The legal market is increasingly displacing the illicit cannabis market in Canada.

Historical Trends in Cannabis Use Among U.S. Adults Ages 19-55, 2013-2021.

OBJECTIVE: The current study used U.S. national data to examine trends in cannabis use from 2013 to 2021, focusing on changes in cannabis prevalence during young and middle adulthood and whether trends differed by sociodemographic characteristics. METHOD: Data from 2013 to 2021 from 21,182 respondents ages 19-30 and 29,871 ages 35-55 in the national Monitoring the Future panel study (followed since they were in 12th grade in 1976-2020) were used to model historical trends in cannabis prevalence (any 12-month use, any 30-day use, and near-daily use [≥20 occasions in the past 30 days]). RESULTS: Prevalence of 12-month, 30-day, and near-daily cannabis use significantly increased from 2013 to 2021 for both young and middle adults. Trends for all three behaviors indicated either consistent linear increases or two-slope increases in which the slope estimate was larger in more recent years. Historical increases in 12-month and 30-day use were similar for young and middle adulthood; the historical increase in near-daily use among middle adults had some evidence for a possible pandemic-related deviation. Historical trends did not differ by race/ethnicity or college degree. Trends for 12-month and 30-day use differed by sex, with women increasing more than men over time, especially during middle adulthood. CONCLUSIONS: Significant increases in the prevalence of cannabis use have occurred over the past decade for young and middle adults across sociodemographic groups, with some indication that near-daily use increased among middle adults at the onset of the pandemic. Although men continue to have a higher prevalence than women, the gap has narrowed, with greater increases in cannabis use among women.

Evolving Disparities in Cannabis Use Among Youth by Demographics and Tobacco and Alcohol Use in the U.S.: 2013-2021.

INTRODUCTION: This study investigated the prevalence of past 30-day cannabis use among U.S. youth by cigarette use, alcohol use, demographics, and state-of-residence cannabis legal status in 2021 and examined whether changes in cannabis use prevalence were modified by these factors from 2013 to 2021. METHODS: Data were drawn from the 24 states that collected cannabis use data participating in the Youth Risk Behavior Surveillance System from 2013 to 2021. Logistic regression analyses estimated past 30-day cannabis prevalence in 2021 and produced AORs by current cigarette, alcohol, and state-of-residence cannabis legal status. The same method was used with year as the exposure, adjusting for sex, race, and ethnicity, to assess trends in prevalence from 2013 to 2021. RESULTS: In 2021, cannabis use was more common among female youth (16.75% vs 13.83% [AOR=1.26, 95% CI=1.16, 1.37]) and non-Hispanic Black and Hispanic youth than among non-Hispanic White youth (17.19%, 16.14% vs 14.60% [AOR=1.25, 95% CI=1.12, 1.39 and AOR=1.16, 95% CI=1.04, 1.29, respectively]). Cannabis use was much more common among youth who reported any past 30-day cigarette or alcohol use (44.90% vs 6.48% [AOR=11.80, 95% CI=10.57, 13.18]). Declines in cannabis use were observed independent of state-level cannabis law from 2013 to 2021, and cannabis use prevalence did not differ significantly by state-of-residence cannabis legal status among the 24 participating states in 2021. CONCLUSIONS: Public health officials should carefully consider the potential impact of expanding commercialization of cannabis as a wellness product on youth cannabis use, especially with regard to minoritized populations and co-use with tobacco and alcohol. National and state-level public health education on cannabis use and youth-oriented prevention of cannabis uptake are long overdue.

Trends and Factors Related to Blunt Use in Middle and High School Students, 2010-2020.

BACKGROUND AND OBJECTIVES: Blunt use is a popular mode of marijuana consumption among adolescents in the United States, but little is known about how its prevalence has changed over time or factors associated with its use. With this study, we assessed trends and correlates of past (ever used but not in the past 30 days) and current (used in past 30 days) blunt use among adolescents in Florida. METHODS: We analyzed data from 2010-2020 cross-sectional, statewide representative Florida Youth Tobacco Surveys that comprised 461 706 middle and high schoolers using Joinpoint to calculate annual percentage change (APC) in the weighted prevalence of past and current blunt use. A weighted multivariable regression model was developed by using 2019-2020 Florida Youth Tobacco Survey data to examine the factors associated with past and current blunt use. RESULTS: Whereas the prevalence of past (APC = -5.32%) and current (APC = -5.28%) blunt use significantly decreased from 2010 to 2015, an increasing trend in current use prevalence (APC = 14.91%) was observed from 2015 to 2018 and has been approximately constant ever since. Similar increasing trends were observed in current blunt use among female students (APC = 14.92%), middle schoolers (19.57%), and non-Hispanic (NH) white students (APC = 11.12%) from 2016 to 2020. Several factors were consistently associated with greater odds of both past and current blunt use for both middle and high schoolers, including older age, being NH Black (versus NH white), past and current use of cigarettes, electronic cigarettes, hookah, cigars, and ever vaping marijuana. CONCLUSIONS: Although blunt use among Florida youth decreased from 2010 to 2015, substantial increases were observed since 2015, suggesting that existing tobacco control programs should incorporate marijuana (and blunt) modules into existing tobacco and nicotine prevention programs.

Acute and Severe Acute Pancreatitis and the Effect of Cannabis in States Before and After Legalization Compared With States Without Legalized Cannabis.

OBJECTIVES: Cannabis legalization has increased its use. The incidence of acute pancreatitis (AP) and severe acute pancreatitis (SAP) has also increased. In this study, data on pancreatitis were obtained from 2 states before and after cannabis legalization and compared with 2 states without legalized cannabis. METHODS: Data were extracted from State Inpatient Databases from the states of Colorado and Washington before recreational cannabis legalization (2011) and after legalization (2015). Arizona and Florida were used as the nonlegalized cannabis states. Multivariable logistic regression models were fit for AP and SAP to determine a trend difference between legalized and nonlegalized cannabis states. RESULTS: Cannabis use, AP, and SAP increased in all states. The increase in AP and SAP was not significantly different between the states that legalized cannabis use and those that did not. Legalized cannabis states had lower charges for AP and SAP and shorter length of hospitalizations. CONCLUSIONS: The trend of AP and SAP increased during the study period, but this was not correlated to cannabis use. Cannabis users had lower hospitalization costs and hospital stay. The effects of other confounders such as cannabis dose and delivery methods, alcohol, tobacco, and others need to be studied further as use increases.

Effect of COVID-19 Pandemic on Cannabis Use in Cancer Patients.

INTRODUCTION: Medical and other cannabis use by cancer patients continues to increase. Reasons for use include management of psychosocial stressors, physical and psychological symptoms. We explored the effect of the coronavirus disease 2019 (COVID-19) pandemic on on patients' cannabis use, hypothesizing that users would be increasing their use due to heightened stress and increased uncertainty. METHODS: Participants were part of an anonymous online survey of cannabis use in cancer. Items specific to COVID-19 were administered between April and June 2020. RESULTS: Thirty-one percent of respondents (n = 26) confirmed they used cannabis during COVID-19. The top 5 reasons for use were sleep, anxiety, nausea, pain, and appetite. Ninety-two percent denied they were using cannabis for new or different symptoms. Eighty-one percent were using about the same amount as before, 11.5% were using less, and 8% more. Only 12% reported that product cost affected their use and that they had changed the way in which they used cannabis. Eight percent were stockpiling product so that they did not run out during the pandemic. CONCLUSIONS: The percentages of those reporting a change in cannabis use were modest. Increased use may reflect efforts to relieve stress. Decreased use may reflect barriers to securing unregulated products and perceived vulnerability to the effects of infection on the respiratory system. As the pandemic continues to evolve, it will be important to monitor its effects on cancer patients as it relates to psychosocial stressors, psychological symptoms, and cannabis use.

Anonymized location data reveals trends in legal Cannabis use in communities with increased mental health risks at the start of the COVID-19 pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has led to increases in felt negative affect for many. This is concerning as individuals at increased risk for mental health issues are often more likely to use substances to cope with stressors. OBJECTIVES: The aim of the current study is to examine whether communities reporting an increased risk for developing mental health issues showed differential patterns of legal cannabis use as the pandemic began. A secondary goal is to examine the feasibility of using anonymized location data to uncover community consumption patterns of potential concern. METHODS: Anonymized location data from approximately 10% of devices in the United States provided a count of the number of visitors to 3,335 cannabis retail locations (medical and recreational) each day from December 1st 2019 through April 2020. Visitor counts were merged with the average number of mentally unhealthy days (aMUDs) reported in the Federal Information Processing Standard (FIPS) county the retailer was located along with FIPS county population and poverty rate estimates. A Poisson spline regression predicting visitors by day, aMUDs, as well as their interaction was performed, entering population and poverty rate as covariates. RESULTS: As the pandemic began communities reporting a greater aMUDs showed greater visitation to cannabis retailers. CONCLUSIONS: These results suggest that the COVID-19 pandemic may have led to increased legal cannabis use in at risk communities. They also highlight the value anonymized location data can provide policymakers and practitioners in uncovering community level trends as they confront an increasingly uncertain landscape.

Online personalized feedback intervention reduces cannabis-related problems among college students with high problem distress.

Despite experiencing problems related to using cannabis, very few undergraduate cannabis users are interested in treatment for cannabis-related problems or benefit from cannabis-focused online personalized feedback interventions (PFIs). Thus, it may be important to determine whether individuals perceive their problems as distressing, as only those who are distressed by their problems may be motivated to change their cannabis use or benefit from cannabis-related interventions. The current study examined cannabis-related problem distress, its relation to motivation to change cannabis use, and whether problem distress impacted outcomes of a problem-focused online PFI. Past-month cannabis-using undergraduates who endorsed experiencing at least one cannabis-related problem in the past 3 months were randomized to a PFI (n = 102) or a personalized normative feedback (PNF)-only condition (n = 102). Problem distress was robustly related to readiness, importance, and confidence to change cannabis use at baseline. Among those with high levels of problem distress at baseline, those in the PFI condition reported a greater decrease in problems than those in the PNF-only condition. This was not the case among those with lower levels of problem distress. Further, the number of cannabis-related problems did not moderate intervention outcomes. Cannabis users who perceive their problems as more distressing may be more motivated to change their cannabis use and more likely to benefit from a problem-focused PFI relative to a PNF-only intervention. Results have implications for the personalization of cannabis-focused interventions to maximize the impacts of interventions and decrease cannabis-related problems. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Refining the marijuana purchase task: Using qualitative methods to inform measure development.

Behavioral economic demand for cannabis (i.e., relative reinforcing value) can be measured via marijuana purchase tasks (MPTs). However, commodity ambiguities pose challenges and design concerns exist regarding current MPTs. The aim of this 2-phase study was to modify and improve a MPT using qualitative methods. Phase I: Focus groups were conducted with regular (i.e., average use ≥ once/week) cannabis users (n = 31; 6-7 per group M[SD] age = 26 [7]; 28% female). Focus groups followed a semistructured agenda, and executive summaries were made concerning key MPT themes. Feedback was used to refine the MPT. Phase II: Cognitive interviews using the refined MPT were conducted with regular cannabis users (n = 20; M[SD] age = 28 [8]; 50% female). Phase I: Focus group analyses highlighted 4 critical areas for MPT improvement: (a) unit of purchase, (b) cannabis quality, (c) time duration specified for use episode, and (d) price. Participants suggested using grams as the unit of purchase, tailoring cannabis quality to the individual, and clarifying intended episode length. Phase II: Cognitive interviewing indicated additional areas for task refinement, resulting in a second iteration of the MPT based on the 2 phases. Qualitative research in both phases suggested a number of substantive modifications to the MPT format. MPT modifications are expected to improve comprehension, ecological validity, and general construct validity. Findings highlight the importance of careful instructional set development for drug purchase tasks for heterogeneous products that do not have standard units of consumption. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Marijuana users are likely to report opioid misuse among adults over 50 years in representative sample of the United States (2002-2014).

Background: In the wake of the rising rate of prescription opioid misuse, there has been increased public health interest in the possibility that cannabis might help to curb or prevent opioid use disorder. Previous studies were limited to young adult marijuana use population. Little is known about whether in older adult population, marijuana use is associated with a different type of nonmedical use opioids. We examined the association between marijuana use and nonmedical prescription opioids dependence and use among older adults.Methods: The National Survey on Drug Use and Health is a nationally U.S. representative cross-sectional survey. We analyzed data for 75,949 adults aged ≥ 50 who participated in the year 2002-2014.Results: Within the overall population, 3.8% of the older adults reported past-year marijuana use (estimate 3.5 million older adults Americans). Past-year marijuana use was very common (25%-37%) among nonmedical opioid dependence respondents compared to those who did not report nonmedical opioid dependence and use (3.5%-3.7%). Past-year marijuana user was significantly associated with an increase in odds of reporting opioid dependence (AOR 9.6 95% CI = 5.8-15.7), and past-year nonmedical use opioids (AOR 6.4 95% CI = 5.2-7.8). Illicit drug heroin was the most prevalent nonmedical used opioid (AOR 6.3 95% CI = 5.0-7.9), compared to codeine (AOR 4.5 95% CI = 3.5-5.7), hydrocodone (AOR 4.9 95% CI = 3.8-6.4), methadone or tramadol (AOR 4.9 95% CI = 2.0-12.3).Conclusion: Policymakers and healthcare providers should remain mindful that older adult marijuana users regardless of initial legitimate medical needs are likely to report nonmedical opioid use including illicit drug heroin.

Predictors of marijuana vaping onset and escalation among young adults.

BACKGROUND: Little is known about factors that influence marijuana vaping among young people. We examined cigarette, e-cigarette and marijuana use experiences, social network characteristics and exposure to direct e-cigarette marketing as predictors of marijuana vaping initiation and escalation. METHODS: One-year prospective data were collected between 2017 and 2019 from 2327 young adults (Mean age = 21.2; SD = 2.1; 54 % women) attending 2-year and 4-year colleges in Hawaii. RESULTS: Among participants who were never marijuana users at baseline, being a dual user of cigarette and e-cigarette at baseline was the strongest predictor of marijuana vaping initiation, followed by baseline cigarette-only and e-cigarette-only use. Higher prevalence of regular marijuana users in one's social networks, but not e-cigarette users or cigarette smokers, significantly predicted marijuana vaping initiation a year later. Among baseline current e-cigarette users and lifetime marijuana users, higher presence in social networks of individuals who frequented vape shops at baseline was a significant predictor of increased current marijuana vaping at one-year follow-up. CONCLUSIONS: Dual use of cigarette and e-cigarette and greater presence in social networks of marijuana users and people who frequent vape shops appear to be robust predictors of marijuana vaping onset and escalation among young adults. In addition to promoting e-cigarette use prevention/cessation, efforts to control marijuana vaping may need to consider promoting smoking prevention/cessation and the effects of increasing prevalence of marijuana use.

Vaping while high: Factors associated with vaping marijuana among youth in the United States.

INTRODUCTION: The use of e-cigarette and other vaping devices have become popular among youth in US. In addition to nicotine, vaping devices can be used to vaporize marijuana. However, factors associated with vaping marijuana among youth remain unexplored. This study examined the rates of vaping marijuana and its correlates among youth in the US. METHODS: We conducted a cross-sectional analysis of survey data from the 2018 National Youth Tobacco Survey of middle-and high-schoolers who provided information regarding ever use of vaping devices to vape marijuana (n = 10,680). Multivariable regression model was conducted to assess factors associated with vaping marijuana. RESULTS: Overall, 26.2 % of participants reported ever vaping marijuana. High-schoolers [vs middle-schoolers; aOR = 2.16,95 %CI:1.76-2.67], Hispanics [vs Whites; aOR = 2.30,95 %CI:1.90-2.80], and Blacks [vs Whites; aOR = 1.42,95 %CI:1.04-1.92] were more likely to ever vape marijuana. Those who perceived e-cigarette as equally addictive to cigarettes, were less likely to ever vape marijuana [aOR = 0.79, 95 %CI:0.65-0.97]. In addition, those who reported ever trying cigarettes [aOR = 1.63,95 %CI:1.29-2.06], cigars [aOR = 2.62, 95 %CI:2.08-3.30], or hookah [aOR = 2.88,95 %CI:2.14-3.89] were more likely to ever vape marijuana. Lifetime frequency of e-cigarette use was associated with greater odds of ever vaping marijuana (p-values <0.001). CONCLUSION: Large numbers of youth in the US have ever vaped marijuana. Our findings indicate that sociodemographic characteristics, tobacco product use, frequency of e-cigarette use are important factors associated with vaping marijuana. Tobacco control campaigns targeted at curbing the use of e-cigarette and other vaping devices among youth in the US should be extended to address vaping substances other than nicotine such as marijuana.

Prospective associations of e-cigarette use with cigarette, alcohol, marijuana, and nonmedical prescription drug use among US adolescents.

BACKGROUND: As e-cigarette use continues to increase in the U.S., research is needed to understand its prospective risk for cigarette smoking and other substance use in young adulthood, including alcohol, marijuana, and nonmedical prescription drugs (NMPDs). METHODS: This study used data from the Monitoring the Future (MTF) study a nationally representative annual survey of 12th graders (modal age 18) in the US. The analytic sample included 2014-2016 MTF cohorts that were selected and completed follow up one year later (modal age 19; n = 717). Using logistic regression, we examined cross-sectional and prospective associations of past 30-day e-cigarette use with past 30-day cigarette, alcohol, marijuana, and NMPD use. We examined prospective associations among the full sample and associations with incidence of each of these substances among those who reported no history of use in 12th grade. RESULTS: In cross-sectional analysis, those who reported past 30-day e-cigarette use at age 18 were more likely to report past 30-day cigarette use, alcohol use, marijuana use, and NMPD use at age 19. In multivariable longitudinal analysis, past 30-day e-cigarette users at age 18 were more likely to report past 30-day cigarette, marijuana, and NMPD use at age 19, including e-cigarette users who had no history of using these substances at age 18. CONCLUSIONS: This study suggests that e-cigarette use may be an indicator of future substance use risk in young adulthood. Adolescent e-cigarette users may benefit from secondary prevention efforts to mitigate this risk.

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

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.

Availability of substances for use in personal vaporisers on three online cryptomarkets.

BACKGROUND: Personal vaporisers are gaining popularity as an alternative route of administration for a range of substances. Online cryptomarkets are becoming increasingly popular among people who use substances due to their perceived anonymity, ease of use, and reduced risk of violence compared to traditional face-to-face dealers. We examined the diversity of substances marketed for use in a personal vaporiser on these marketplaces. METHODS: Vaping related listings were extracted from three online cryptomarkets ('Agartha', 'Cryptonia', and 'Tochka') using The Onion Router browser. Data collection occurred between October and November 2019. RESULTS: We identified 1929 listings from 201 unique sellers. The top product on Agartha, Cryptonia, and Tochka were vape cartridges prefilled with the e-liquid (70.4 %, 39.4 %, 52.3 % respectively). The most common substance in these products was cannabis oil (96.1 %, 82.1 %, 87.8 %), followed by synthetic cannabinoids (3.7 %, 9.7 %, 9.8 %) and psychedelic substances (0.2 %, 6.4 %, 1.2 %). Vendors were primarily from the USA. Many products offered worldwide shipping (96.3 %, 42.4 %, 51.2 %). CONCLUSION: Vaping products listed on online cryptomarkets in 2019 primarily contained cannabis oils. Future studies should continue to examine cryptomarkets to identify emerging trends of substances that can be used in personal vaporisers.

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

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

Changes in the Order of Cigarette and Marijuana Initiation and Associations with Cigarette Use, Nicotine Vaping, and Marijuana Use: U.S. 12th Grade Students, 2000-2019.

This study (a) examined changes in marijuana and cigarette initiation sequencing and (b) considered implications of such changes for prevention efforts by examining associations between initiation sequencing and current adolescent substance use. Analyses used 2000-2019 cross-sectional data from the national Monitoring the Future (MTF) study (78,252 U.S. 12th grade students). Models examined trends in six distinct patterns of initiation order, and multivariable associations between order of initiation and 30-day cigarette and marijuana use prevalence, cigarette and marijuana use frequency among users, and nicotine and marijuana vaping prevalence. While the percentage of students initiating neither cigarettes nor marijuana increased, increases also were observed in marijuana-only initiation (the fastest-growing pattern) and initiation of marijuana before cigarettes; these increases were accompanied by a significant decrease in cigarette-only initiation. Cigarette use prevalence and frequency were highest among students initiating cigarettes before marijuana; marijuana use prevalence and frequency were highest among students initiating marijuana before cigarettes. Cigarette and marijuana prevalence, as well as marijuana frequency, were lowest among students initiating only a single substance. Nicotine vaping was less prevalent among students initiating a single substance versus both substances, but no significant differences were observed in nicotine vaping prevalence between those initiating only cigarettes versus only marijuana. Implications of these findings for prevention efforts are discussed in the frameworks of both the common liability model and route of administration model.

Trends and correlates of cannabis use in Canada: a repeated cross-sectional analysis of national surveys from 2004 to 2017.

BACKGROUND: Cannabis is the most widely used drug in Canada. We examined the trends in past-year cannabis consumption by sociodemographic and geographic characteristics. METHODS: We conducted a repeated cross-sectional analysis of the Canadian Tobacco Use Monitoring Survey, the Canadian Tobacco, Alcohol and Drugs Survey and the Canadian Alcohol and Drug Use Monitoring Survey from 2004 to 2017. Respondents were aged 15 years and older. Past-year cannabis use was analyzed using multivariable logistic regression and segmented logistic regression. RESULTS: We analyzed 289 823 respondents (51% female) between 2004 and 2017. Between 2004 and 2017, the overall prevalence of cannabis use increased from 12.2% (95% confidence interval [CI] 11.0%-13.5%) to 18.7% (95% CI 16.2%-21.5%) among men and from 6.6% (95% CI 5.9%-7.4%) to 11.1% (95% CI 9.4%-13.0%) among women. The crude rate of change was greater between 2011 and 2017 than that between 2004 and 2011 in men (odds ratio [OR] per annual change: 1.08, 95% CI 1.05-1.11) and women (OR 1.11, 95% CI 1.07-1.15). After adjustment for age, education, tobacco smoking and province, the 2011-2017 trend was stronger in men (adjusted OR 1.24, 95% CI 1.05-1.46), but not in women (adjusted OR 1.13, 95% CI 0.93-1.37). Cannabis use was associated with tobacco smoking (OR 4.94, 95% CI 4.65-5.25). Heterogeneity was found in cannabis use trends by age, education and province. Cannabis use decreased among respondents aged 15-19 years and increased in other age groups. INTERPRETATION: Cannabis consumption in Canada has increased and varies by sex, age, level of education and geography. Increases vary by sociodemographic factors and may be faster among certain groups. Further studies are warranted post-legalization.