Cannabis legalization, tobacco prevention policies, and Cannabis use in E-cigarettes among youth

Public Health Interventions Targeting the Prevention of Adolescent Vaping: A Scoping Review

OBJECTIVE

Despite a brief decline during the COVID-19 pandemic, vaping behaviors among adolescents continue to be an international public health concern because of associated health risks and harms. A thorough investigation of existing interventions preventing adolescent vaping is needed to help address this public health crisis and reduce serious and avoidable vaping-related health risks. We reviewed the literature to identify public health interventions aimed at preventing adolescent vaping and summarized their key components and outcome measures.

DESIGN

We conducted a scoping review of the literature using the Joanna Briggs Institute methodology searching in MEDLINE, CINAHL, Embase, PubMed, PsycINFO, ProQuest, and Web of Science. Two reviewers screened 589 records for relevance. Studies from any location, reported in English, and described vaping prevention interventions targeting adolescents were included. Records were excluded if they were reported in other languages, published outside the review timeframe, lacked an evaluation, focused on cessation-based interventions, or were review articles. Data extracted included intervention type, key components, and outcome measures.

RESULTS

Thirty-eight included articles were identified and categorized into three intervention categories: school-based, public education/risk communication campaigns, and public policies/government regulations. Key components of the interventions included format, duration, and topics. Formats varied from single to multi-sessions. Prominent topics covered included risks and harms associated with vaping, and the most frequently reported outcome measures used were knowledge, attitudes, and beliefs.

CONCLUSION

Our findings summarize existing public health interventions found in the literature and insights into approaches used to address the global adolescent vaping crisis.

A systematic review and network meta-analysis of population-level interventions to tackle smoking behaviour

This preregistered systematic review and meta-analysis (PROSPERO: CRD 42022311392) aimed to synthesize the effectiveness of all available population-level tobacco policies on smoking behaviour. Our search across 5 databases and leading organizational websites resulted in 9,925 records, with 476 studies meeting our inclusion criteria. In our narrative summary and both pairwise and network meta-analyses, we identified anti-smoking campaigns, health warnings and tax increases as the most effective tobacco policies for promoting smoking cessation. Flavour bans and free/discounted nicotine replacement therapy also showed statistically significant positive effects on quit rates. The network meta-analysis results further indicated that smoking bans, anti-tobacco campaigns and tax increases effectively reduced smoking prevalence. In addition, flavour bans significantly reduced e-cigarette consumption. Both the narrative summary and the meta-analyses revealed that smoking bans, tax increases and anti-tobacco campaigns were associated with reductions in tobacco consumption and sales. On the basis of the available evidence, anti-tobacco campaigns, smoking bans, health warnings and tax increases are probably the most effective policies for curbing smoking behaviour.

Products and patterns through which adolescents, young adults, and adults initiate co-use of tobacco and cannabis

BACKGROUND

Co-use of tobacco and cannabis is common. However, few studies have examined the temporal sequencing through which individuals initiate co-use, and how these patterns vary across age. This study addresses this gap by examining the specific products and temporal sequencing through which adolescents, young adults, and adults initiate co-use of tobacco and cannabis. Among adolescents, young adults, and adults who co-used tobacco and cannabis in the past 30 days, we examined (a) whether tobacco or cannabis was used first in their lifetime and (b) which specific tobacco or cannabis product (e.g., nicotine e-cigarettes, cannabis edibles) was the first used.

METHODS

Data were from a cross-sectional national survey (N = 6,131, 13-40 years old) in which participants reported ever use, past-30-day-use, and order of use for 17 different tobacco and cannabis products. Results were analyzed overall and by age group (13-20; 21-24; 25-40).

RESULTS

38.4% of participants reported use of both tobacco and cannabis in the past 30 days. Among these participants, 70.9% used tobacco first in their lifetime (66.6% < 21; 71.7% 21-24; 76.6% > 24). Approximately 60% of participants who initiated co-use with tobacco reported nicotine e-cigarettes as their first tobacco product (63.3% < 21; 66.7% 21-24; 49.6% > 24).

CONCLUSIONS

The majority of participants who used both tobacco and cannabis used tobacco first in their lifetime, and nicotine e-cigarettes were the most common form of tobacco initiation, particularly among adolescents and young adults. Findings emphasize the need for co-use prevention programs to target common products of initiation.

Clinician perspectives on adolescent cannabis-related beliefs and behaviors following recreational cannabis legalization

BACKGROUND

As more states legalize cannabis, studies are needed to understand the potential impacts of recreational cannabis legalization (RCL) on adolescents from the perspective of clinicians who care for them.

METHODS

This qualitative study characterized clinician perspectives on whether cannabis legalization is associated with changes in adolescents' cannabis use beliefs, behaviors, and consequences. Semi-structured qualitative interviews were conducted with 32 clinicians in a large healthcare organization from 9/6/2022-12/21/2022. Video-recorded interviews were transcribed and analyzed using thematic analysis.

RESULTS

The 32 participants (56.3 % female, mean [SD] age, 45.9 [7.6] years; 65.3 % non-Hispanic White) were from Addiction Medicine (n = 13), Psychiatry/Mental Health (n = 7), Pediatrics (n = 5), and the Emergency Department (n = 7). Clinicians described post-RCL increases in adolescent cannabis use, use of non-combustible modes and high-potency products, and younger age of first use. Clinicians reported social, physical, and policy changes, including changes in social norms, appealing advertisements, marketing, and easier access. Many noted fewer perceived harms among adolescents and greater self-medication post-RCL. They described how RCL contributed to increased parental cannabis use and permissiveness around adolescent use. Finally, many described post-RCL increases in cannabis hyperemesis syndrome, and several noted increased cannabis-related psychosis and acute intoxication, and decreased court-mandated treatment.

CONCLUSIONS

Clinicians from diverse specialties described post-RCL increases in adolescent cannabis use and cannabis-related consequences, alongside changes in social norms, access, marketing and advertisements, and decreased perceptions of harms. Findings can inform strategies to support adolescents in the context of increased cannabis availability and acceptability post-legalization and support the development of hypotheses for broader-scale quantitative work.

Immigration status-related exclusive e-cigarette use and cannabis use and their dual use disparities associated with mental health disorder symptoms

INTRODUCTION

E-cigarette and cannabis use has been linked to various health risks, including respiratory and cardiovascular conditions. Yet, extant knowledge about the risk factors for exclusive and dual use of e-cigarettes and cannabis is limited, especially among immigrants. We examined exclusive e-cigarette and cannabis use and their dual use associated with mental health disorders among immigrants and U.S.-born.

METHODS

We analyzed national cross-sectional data collected between May 13, 2021, and January 9, 2022, among adults aged >18 years (n= 4766) living in U.S. Multinomial logistic regression analyses were conducted to model the associations of exclusivity and dual-use (reference group= non-use) with anxiety/depression.

RESULTS

The dual-use prevalence was higher than exclusive e-cigarette and cannabis use, especially among U.S.-born (dual use= 14.79% vs. cannabis use= 13.53% vs. e-cigarette use= 7.11%) compared to immigrants (dual use= 8.23% vs. cannabis use= 5.03% vs. e-cigarette use= 6.31%). Immigrants had lower risks of exclusive cannabis and dual use compared to U.S.-born. Anxiety/depression was associated with higher risks of exclusive cannabis use and dual use across immigration status, but was associated with exclusive e-cigarette use among only immigrants. While effect sizes of dual-use associated with anxiety/depression were higher among U.S.-born, the effect sizes of exclusive e-cigarette and cannabis use associated with anxiety/depression were higher among immigrants.

CONCLUSIONS

The findings revealed significant mental health risks for e-cigarette, cannabis, and their dual use among immigrants and U.S.-born, especially among U.S.-born. These findings highlight the need for public health research and interventions to consider immigration status-related disparities in substance use.

Legalization and retail availability of recreational marijuana and adolescent use in schools

Legalization of use and retail sales of recreational marijuana in U.S. states and the associated potential increase in access to marijuana and normalization of its use by adults could lead to increased use by adolescents. Studies have found that states with legal recreational marijuana have higher rates of adolescent use and frequency of use compared to states without legal use. We examined changes in student office discipline referrals (ODRs) for substance use offenses in Oregon middle and high schools before and after the legalization of recreational marijuana relative to comparison schools in other states. We found that rates of substance use related ODRs in middle schools increased by 0.14 per 100 students (30% of the mean) with legalization relative to comparison schools. This increase was moderated by the presence of a marijuana outlet within one mile of the school. We found no statistically discernible changes in high school ODRs. Marijuana use in adolescence has been linked to negative health and social consequences, including academic problems, mental health issues, and impaired driving. Potential adverse impact on adolescents and investments in school-based prevention programs could be important considerations for policymakers and public health officials when evaluating marijuana legalization.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

Health, safety, and socioeconomic impacts of cannabis liberalization laws: An evidence and gap map

Background

Globally, cannabis laws and regulations are rapidly changing. Countries are increasingly permitting access to cannabis under various decriminalization, medicalization, and legalization laws. With strong economic, public health, and social justice incentives driving these domestic cannabis policy reforms, liberalization trends are bound to continue. However, despite a large and growing body of interdisciplinary research addressing the policy-relevant health, safety, and socioeconomic consequences of cannabis liberalization, there is a lack of robust primary and systematic research that comprehensively investigates the consequences of these reforms.

Objectives

This evidence and gap map (EGM) summarizes the empirical evidence on cannabis liberalization policies. Primary objectives were to develop a conceptual framework linking cannabis liberalization policies to relevant outcomes, descriptively summarize the empirical evidence, and identify areas of evidence concentration and gaps.

Search Methods

We comprehensively searched for eligible English-language empirical studies published across 23 academic databases and 11 gray literature sources through August 2020. Additions to the pool of potentially eligible studies from supplemental sources were made through November 2020.

Selection Criteria

The conceptual framework for this EGM draws upon a legal epidemiological perspective highlighting the causal effects of law and policy on population-level outcomes. Eligible interventions include policies that create or expand access to a legal or decriminalized supply of cannabis: comprehensive medical cannabis laws (MCLs), limited medical cannabidiol laws (CBDLs), recreational cannabis laws (RCLs), industrial hemp laws (IHLs), and decriminalization of cultivations laws (DCLs). Eligible outcomes include intermediate responses (i.e., attitudes/behaviors and markets/environments) and longer-term consequences (health, safety, and socioeconomic outcomes) of these laws.

Data Collection and Analysis

Both dual screening and dual data extraction were performed with third person deconfliction. Primary studies were appraised using the Maryland Scientific Methods Scale and systematic reviews were assessed using AMSTAR 2.

Main Results

The EGM includes 447 studies, comprising 438 primary studies and nine systematic reviews. Most research derives from the United States, with little research from other countries. By far, most cannabis liberalization research focuses on the effects of MCLs and RCLs. Studies targeting other laws-including CBDLs, IHLs, and DCLs-are relatively rare. Of the 113 distinct outcomes we documented, cannabis use was the single most frequently investigated. More than half these outcomes were addressed by three or fewer studies, highlighting substantial evidence gaps in the literature. The systematic evidence base is relatively small, comprising just seven completed reviews on cannabis use (3), opioid-related harms (3), and alcohol-related outcomes (1). Moreover, we have limited confidence in the reviews, as five were appraised as minimal quality and two as low quality.

Authors’ Conclusions

More primary and systematic research is needed to better understand the effects of cannabis liberalization laws on longer-term-and arguably more salient-health, safety, and socioeconomic outcomes. Since most research concerns MCLs and RCLs, there is a critical need for research on the societal impacts of industrial hemp production, medical CBD products, and decriminalized cannabis cultivation. Future research should also prioritize understanding the heterogeneous effects of these laws given differences in specific provisions and implementation across jurisdictions.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

Thermal Degradants Identified from the Vaping of Vitamin E Acetate

Studies have suggested that vitamin E acetate (VEA), when used in an electronic vaping device, undergoes thermal degradation and is considered one of the main contributors in e-cigarette or vaping product use-associated lung injury (EVALI). Using a Borgwaldt 5.1 linear smoker, a SVS250 Electronic Vaporizer and two types of tank systems, VEA was analyzed for degradation products produced via the Cooperation Centre for Scientific Research Relative to Tobacco method 81 when the filter containing vaporized VEA was extracted using acetonitrile. Two of the major products identified were 2,3,5,6-tetramethyl-1,4-benzoquinone and 2,6,10,14-tetramethyl-1-pentadecene, which were confirmed using analytical standards and gas chromatography-high-resolution mass spectrometry (GC-HRMS). Additional synthesis of 4-acetoxy-2,3,5,6-tetramethyl-2,4-cyclohexadienone and subsequent characterization using nuclear magnetic resonance and GC-HRMS suggested that this is not one of the products produced. Identification of these degradants will allow future studies to quantify and examine the degradants in vivo and in vitro as biomarkers for exposure and toxicity assessment.

“Returning to Ordinary Citizenship”: A Qualitative Study of Chinese PWUD’s Self-Management Strategies and Disengagement Model of Identity

How PWUD (people who use drugs) live under drug governance is an important research question. This study adopts a qualitative research method to explore how PWUD in China self-manage after perceiving the dilemma of incomplete citizenship and the social pressure brought by drug control arrangements. Through analysis of 130 PWUD’s files and in-depth interviews with 10 interviewees (from the 24 preliminary interviews), this study found that PWUD developed action strategies of hidden mobility (spatial isolation), disconnection of past experiences (time isolation), instrumental actions, as well as narrative strategies of reframing themselves as ordinary citizens with attempts of reversing identity disadvantages. Further, PWUD’s self-management strategies manifest as a disengagement model in which the actors (PWUD, not rehabilitation agencies) do not intend to develop integrative positive identities through dispersed, practiced behavioral strategies, but attempt to return to pre-addiction, non-socially exclusionary citizenship experiences. The disengagement model and its negative effect on PWUD’s social integration help us reflect on the current implementation of rehabilitation projects and institutional settings of drug governance.

Longitudinal Associations Between Use of Tobacco and Cannabis Among People Who Smoke Cigarettes in Real-world Smoking Cessation Treatment

OBJECTIVES

Cannabis use is common among people who use tobacco. However, little is known about the relationship between change in use of tobacco and cannabis over time. We examined the longitudinal associations between use of the two substances in a realworld smoking cessation context.

METHODS

This study analyzed data from a 3-month smoking cessation program delivered via Facebook in the San Francisco Bay Area, USA during 2016-2020. The sample included 487 participants who smoked cigarettes ( Mage = 25.4 years old, 39.6% Male, 40.3% White). The regressors (ie, frequency or number of days during the past 30 days using cigarettes, e-cigarettes, and cigars) and the outcome (ie, frequency of cannabis use) were measured at both baseline and 3-month follow-up. Random-effects modeling examined the longitudinal associations between the regressors and the outcome controlling for alcohol use and baseline demographics.

RESULTS

Participants who increased (or decreased) their frequency of use of cigarettes (β = 0.17, 95% confidence interval [CI] = 0.10, 0.24), e-cigarettes (β = 0.11, 95% CI = 0.05, 0.17), or cigars (β = 0.19, 95% CI = 0.06, 0.32) also increased (or decreased) their frequency of cannabis use after 3 months. Sexual minority participants (vs heterosexuals) (β = 2.12, 95% CI = 0.01, 4.24) and those whose education attainment being high school or less (vs higher education) (β = 3.89, 95% CI = 1.25, 6.53) were more likely to increase their frequency of cannabis use over time.

CONCLUSIONS

The findings indicated positive associations between change in use of tobacco and cannabis use. Promoting cessation among people who use tobacco may help to reduce their cannabis use.

A difference-in-difference approach to examining the impact of cannabis legalization on disparities in the use of cigarettes and cannabis in the United States, 2004-17

AIMS

To estimate the impact of recreational and medical cannabis laws (RCL, MCL) on the use of cannabis and cigarettes in the United States.

DESIGN

A difference-in-difference approach was applied to data from the 2004-17 National Survey on Drug Use and Health (NSDUH).

SETTING

United States.

PARTICIPANTS

Nationally representative cross-sectional survey of Americans aged 12 years and older (combined analytical sample for 2004-17, n = 783 663).

MEASUREMENTS

Data on past-month use of (1) cigarettes and (2) cannabis were used to classify respondents into four groups: cigarette and cannabis co-use, cigarette-only use, cannabis-only use or no cigarette or cannabis use. State of residence was measured by self-report. MCL/RCL status came from state government websites.

FINDINGS

Difference-in-difference analyses suggest that MCL was associated with an increase in cigarette-cannabis co-use overall [adjusted odds ratio (aOR) = 1.09; 95% confidence interval (CI) = 1.02-1.16], with the greatest increases among those aged 50 years and above (aOR = 1.60; CI = 1.39-1.84), married (aOR = 1.19; CI = 1.07-1.31), non-Hispanic (NH) black (aOR = 1.14; CI = 1.02-1.07) and with a college degree or above (aOR = 1.15; CI = 1.06-1.24). MCL was associated with increases in cigarette-only use among those aged 50 years and above (aOR = 1.07; CI = 1.01-1.14) and NH black (aOR = 1.16; CI = 1.06-1.27) and increases in cannabis-only use among those aged 50 years and above (aOR = 1.24; CI = 1.07-1.44) and widowed/divorced/separated (aOR = 1.18; CI = 1.01-1.37). RCL was associated with an increase in cannabis-only use overall (aOR = 1.21; 95% CI = 1.09-1.34), a decline in cigarette-only use overall (aOR = 0.89; 95% CI = 0.81-0.97) and increases in co-use among those who were married (aOR = 1.24; CI = 1.02-1.50) and aged 50 years and above (aOR = 1.37; CI = 1.03-1.84).

CONCLUSIONS

Recreational and medical cannabis legalization have had a varying impact on the use, and co-use, of cannabis and cigarettes in the United States.

Cannabis Vaping Among Youth and Young Adults: a Scoping Review

Purpose of Review

The purpose of this review was to describe the state-of-the-literature on research specific to cannabis vaping among youth and young adults.

Recent Findings

Out of 1801 records identified, a total of 202 articles met eligibility criteria for inclusion in this review. Most of this literature (46.0% of studies) was specific to the health effects of cannabis vaping, particularly EVALI (e-cigarette and vaping associated lung injury). Other research areas identified in the review included the etiology (24.3%) and epidemiology (24.8%) of cannabis vaping, in addition to articles on regulation (8.4%) and marketing (5.5%) of the same.

Summary

Cannabis vaping is increasingly common among youth and young adults and more prevalent is settings where recreational use for adults has been legalized. The literature documents a number of negative health effects of cannabis vaping for young people, along with risk factors and reasons for the same.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40429-022-00413-y.

Effects of combined THC and heroin vapor inhalation in rats

RATIONALE

Opioids are effective medications, but they have several key limitations including the development of tolerance, establishment of dependence, diversion for non-medical use, and the development of addiction. Therefore, any drugs which act in an additive or synergistic fashion with opioids to address medical applications have the potential to reduce opioid-related harms.

OBJECTIVES

To determine if heroin and Δ9-tetrahydrocannabinol (THC) interact in an additive or independent manner to alter nociception, body temperature, and spontaneous locomotor activity when inhaled or injected.

METHODS

Groups of female and male rats, implanted with radiotelemetry transmitters, were exposed to vapor generated from heroin (50 mg/mL in propylene glycol vehicle; PG), THC (50 mg/mL), or the combination for assessment of effects on temperature and activity. Thermal nociception was assessed with a warm water tail-withdrawal assay.

RESULTS

Heroin inhalation increased temperature and activity whereas THC inhalation decreased temperature and activity in both female and male Sprague-Dawley rats. Effects of combined inhalation were in opposition, and additional experiments found the same outcome for the injection of heroin (0.5 mg/kg, s.c.) and THC (10 mg/kg, i.p.) alone and in combination. In contrast, the co-administration of heroin and THC by either inhalation or injection produced additive effects on thermal nociception in both male and female Sprague-Dawley and Wistar rats.

CONCLUSIONS

This study shows that additive effects of THC with an opioid on a medical endpoint such as analgesia may not generalize to other behavioral or physiological effects, which may be a positive outcome for unwanted side effects.

Effect modification of legalizing recreational cannabis use on the association between e-cigarette use and future cannabis use among US adolescents

BACKGROUND

Many states have legalized recreational cannabis use for adults. However, no study has examined how this policy may interact with youth vaping to influence cannabis use among US adolescents. This study investigates whether the association between baseline e-cigarette use and subsequent cannabis use differs by state recreational cannabis legalization status.

METHODS

This study analyzed data from the first four waves (2013-2018) of the Population Assessment of Tobacco and Health Study, a nationally representative longitudinal survey. The study sample included adolescents (aged 12-17) who reported never used cannabis at baseline. Generalized estimating equations were used to analyze the effect modification of state recreational cannabis law on the association between baseline e-cigarette use and cannabis use at 12-month follow-up, controlling for individual characteristics.

RESULTS

Among adolescents who have never used cannabis at baseline, baseline past-30-day e-cigarette use was significantly associated with past-30-day cannabis use at 12-month follow-up (aOR=5.92, 95% CI: 3.52-9.95). This association was different by state recreational cannabis legalization status, as indicated by the significant interaction term. Subgroup analysis showed that the aOR was 18.39 (95% CI: 4.25-79.68) for adolescents living in states that legalized adult recreational cannabis use and 5.09 (95% CI: 2.86-9.07) for adolescents living in states without such laws.

CONCLUSIONS

E-cigarette use is associated with cannabis initiation among youth. This association is stronger among those living in states that legalized adult recreational cannabis use. Further examination of the impact of e-cigarette use on cannabis initiation in relation to state cannabis laws is warranted.

The Effects of Nicotine and Cannabis Co-Use During Late Adolescence on White Matter Fiber Tract Microstructure

OBJECTIVE

Co-use of cannabis and nicotine and tobacco products (NTPs) in adolescence/young adulthood is common and associated with worse outcomes than the use of either substance in isolation. Despite this, little is known about the unique contributions of co-use to neurostructural microstructure during this neurodevelopmentally important period. This study sought to investigate the interactive effects of nicotine and cannabis co-use on white matter fiber tract microstructure in emerging adulthood.

METHOD

A total of 111 late adolescent (16-22 years old) nicotine (NTP; n = 55, all past-year cannabis users) and non-nicotine users (non-NTP; n = 56, 61% reporting cannabis use in the past year) completed demographic and clinical interviews and a neuroimaging session comprising anatomical and diffusion-weighted imaging scans. Group connectometry analysis identified white matter tracts significantly associated with the interaction between nicotine group and past-year cannabis use according to generalized fractional anisotropy (GFA).

RESULTS

Nicotine Group × Cannabis Use interactions were observed in the right and left cingulum and left fornix tracts (false discovery rate = 0.053), where greater cannabis use was associated with increased GFA in the cingulum and left fornix, but only when co-used with nicotine.

CONCLUSIONS

This report represents the first group connectometry analysis in late adolescent/young adult cannabis and/or NTP users. Results suggest that co-use of cannabis and NTPs results in a structurally distinct white matter phenotype as compared with cannabis use only, although to what extent this may change over time with more chronic nicotine and cannabis use remains to be examined in future work.

The Effects of Nicotine and Cannabis Co-Use During Late Adolescence on White Matter Fiber Tract Microstructure

OBJECTIVE

Co-use of cannabis and nicotine and tobacco products (NTPs) in adolescence/young adulthood is common and associated with worse outcomes than the use of either substance in isolation. Despite this, little is known about the unique contributions of co-use to neurostructural microstructure during this neurodevelopmentally important period. This study sought to investigate the interactive effects of nicotine and cannabis co-use on white matter fiber tract microstructure in emerging adulthood.

METHOD

A total of 111 late adolescent (16-22 years old) nicotine (NTP; n = 55, all past-year cannabis users) and non-nicotine users (non-NTP; n = 56, 61% reporting cannabis use in the past year) completed demographic and clinical interviews and a neuroimaging session comprising anatomical and diffusion-weighted imaging scans. Group connectometry analysis identified white matter tracts significantly associated with the interaction between nicotine group and past-year cannabis use according to generalized fractional anisotropy (GFA).

RESULTS

Nicotine Group × Cannabis Use interactions were observed in the right and left cingulum and left fornix tracts (false discovery rate = 0.053), where greater cannabis use was associated with increased GFA in the cingulum and left fornix, but only when co-used with nicotine.

CONCLUSIONS

This report represents the first group connectometry analysis in late adolescent/young adult cannabis and/or NTP users. Results suggest that co-use of cannabis and NTPs results in a structurally distinct white matter phenotype as compared with cannabis use only, although to what extent this may change over time with more chronic nicotine and cannabis use remains to be examined in future work.

Exploring Patterns of the Use of Electronic Nicotine Delivery Systems among Adolescents in High-Risk Appalachian (U.S.A) Communities

Background: Electronic nicotine delivery systems (ENDS) use among adolescents in the United States (U.S.) has surpassed conventional tobacco products (CTPs), including cigarettes. Increasingly, ENDS are used concurrently with CTPs and substances such as cannabis. However, few studies involve Central Appalachia, a region with historically high rates of tobacco and other substance use. Objective:  To examine prevalence of concurrent use of ENDS and cannabis among school-going adolescents in Appalachian Tennessee and delineate associations between ENDS use and substance-related risk behavior (cannabis use), social relations (peer use), and school-related risk behavior (academic performance). Methods: Data were obtained from a survey conducted with youth aged 13-17 years in 2018 in a county in Appalachian Tennessee (n = 280). A multivariable logistic regression model was fit to evaluate associations between ENDS and cannabis use, and other factors. Results: Overall, lifetime ENDS and cannabis prevalence estimates were 31.1% and 18.6%, respectively. Lifetime ENDS users had increased odds of also being lifetime cannabis users [OR = 9.22, 95% confidence interval (CI): 3.44-24.75]. Lifetime ENDS users had increased odds of reporting ENDS use among peers [OR = 12.11; 95% CI: 5.40-27.12] and lower academic performance (OR associated with mostly C or D vs. A grades was 4.28, 95% CI: 1.68-10.90). Conclusion: This study found an association between ENDS and cannabis use among adolescents in Appalachian Tennessee exists. Additionally, peer use and academic performance were associated with ENDS use. The findings have implications for public health intervention planning to address not only ENDS but also substance use among Appalachian youth.

Prevalence of Adolescent Cannabis Vaping: A Systematic Review and Meta-analysis of US and Canadian Studies

IMPORTANCE

Vaping products were initially designed to deliver nicotine as a tobacco cigarette substitute (eg, electronic cigarettes) but are now frequently used to deliver psychoactive substances, such as cannabis and its derivatives. Large, nationally representative surveys, such as Monitoring the Future, found that approximately 1 in 3 grade-12 students vaped cannabis in 2018 alone.

OBJECTIVE

To summarize the findings of epidemiological studies that reported the global prevalence of cannabis vaping in adolescents by survey year and school grades.

DATA SOURCES

PubMed, PsycINFO, Scopus, and Web of Science were searched systematically on August 19, 2020, for studies published globally between January 1, 2003, and August 19, 2020.

STUDY SELECTION

Publications that reported the prevalence of cannabis vaping in adolescents in the general population were included.

DATA EXTRACTION AND SYNTHESIS

Study characteristics and prevalence estimates were extracted from each article. Random-effects meta-analysis based on the DerSimonian and Laird method and meta-regression were performed on lifetime, 12-month, and 30-day prevalence estimates. Meta-regression was also conducted using survey year and school grades as moderators.

MAIN OUTCOMES AND MEASURES

Prevalence of cannabis vaping.

RESULTS

Seventeen studies met the eligibility criteria (n = 198 845 adolescents). Although no restrictions were imposed on study location, all 17 studies were from the US and Canada. Across all school grades, the pooled prevalence increased for lifetime use (6.1% in 2013-2016 to 13.6% in 2019-2020), use in the past 12 months (7.2% in 2017-2018 to 13.2% in 2019-2020), and use in the past 30 days (1.6% in 2013-2016 to 8.4% in 2019-2020). Heterogeneity across studies was large. The limited evidence from studies using similar survey and study designs suggested that adolescents' preference for cannabis products other than dried herbs, which usually contain higher Δ9-tetrahydrocannabinol levels, may have shifted over time.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that the prevalence of cannabis vaping has increased among adolescents in the US and Canada and that more effective preventive and response measures are required.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42020219644.

Cannabis Legalization and Adolescent Use of Electronic Vapor Products, Cannabis, and Cigarettes

OBJECTIVES

Cannabis legalization may have unintended consequences, such as effects on prevalence of adolescent use of other substances. We hypothesize that in states that have legalized recreational cannabis (RCL states), electronic vapor product use ("vaping"), cannabis, and cigarette use among adolescents is more prevalent than in states that have only legalized medical cannabis (MCL states) and states that have neither legalized recreational nor medical cannabis (NL states).

METHODS

Data are from the Center for Disease Control's 2017 Youth Risk Behavior Surveillance Survey (n = 107,665), a nationally representative survey of US high school students. We categorized student responses by cannabis legalization status of the state in which they lived at time of survey, then tested associations between cannabis legalization status and adolescent vaping, cannabis, and cigarette use, using logistic regressions.

RESULTS

Students in RCL states were significantly more likely to report current vaping behaviors compared to NL students [odds ratios (OR's) 2.07-2.21]. Students in cannabis-legal states were significantly more likely to report ever or currently using cannabis compared to NL students (OR's 1.27-1.40). MCL students were significantly less likely to report current cigarette smoking (OR = 0.86) compared to NL students.

CONCLUSIONS

Adolescents in cannabis-legal states were more likely to report vaping and cannabis use compared to adolescents in NL states. Public health officials, policymakers, and clinicians should consider the associations between cannabis legalization and adolescent vaping, cigarette, and cannabis use patterns.

Changes in cannabis use modes among Canadian youth across recreational cannabis legalization: Data from the COMPASS prospective cohort study

INTRODUCTION

Canadian youth consume cannabis in multiple ways, including by smoking, vaping, and eating or drinking. Existing evidence suggests that these behaviours may change after law liberalization, though data regarding youth are scarce. We investigated changes in cannabis modes of use and associated factors across the federal legalization of recreational cannabis use for adults in Canada, among a large sample of underage youth before alternative products were made legally available.

METHODS

Data were available from 2953 longitudinally linked Canadian high school students who reported on their cannabis use during the 2017/2018 and 2018/2019 school years. We explored whether students maintained a single or multiple cannabis use mode(s), contracted, or expanded the number of modes used. We then used generalized estimating equations to analyse associations of baseline characteristics with use mode trajectory.

RESULTS

Expansion of cannabis use modes (42.3%) was more common than maintenance of a single mode (31.3%), maintenance of multiple modes (14.3%), or reduction (12.1%). Students who maintained multiple modes were significantly more likely to have high amounts of weekly spending money (AOR 1.68), to binge drink (AOR 2.25) or vape (AOR 1.99), to use cannabis regularly (AOR 2.67), and to endorse more symptoms of depression (AOR 1.06). School support for quitting tobacco, drug, or alcohol use appeared to have no effect.

CONCLUSIONS

Multi-modal cannabis use increased among Canadian youth in our sample. Its association with other substance use and depressive symptoms may indicate clustering of additional harms. Screening for this use pattern may assist in identifying high-risk substance use and should be considered in the design of harm reduction programming.

Use of electronic cigarettes as a predictor of cannabis experimentation: A longitudinal study among German youth

INTRODUCTION

Experimentation with e-cigarettes is rising among youth, and there are concerns that e-cigarettes could be a new risk factor for initiating substance use. This study aimed to investigate whether e-cigarette use longitudinally predicts experimentation with cannabis.

METHODS

During 2017-2019, a prospective cohort study with an observation period of 18 months was conducted with 3,040 students from Germany who had never used cannabis (mean age = 14.8, range: 13-18 years). A multiple poisson regression was used to investigate whether e-cigarette use was an independent predictor of future cannabis use.

RESULTS

Lifetime e-cigarette use was reported by 29.4 % of the survey population (n = 894) at baseline, and 17.4 % (n = 529) initiated cannabis use during the observation period. Among e-cigarette ever users, the initiation rate was 34.5 % compared to 10.4 % of never users. Results were robust to adjustment for age, sex, migrant status, type of school, sensation seeking, peer cannabis use, the use of alcohol and conventional cigarettes (ARR = 1.83; 95 % CI: 1.48-2.25). Further analyses revealed that the association between e-cigarette use and cannabis experimentation was stronger among youth with low sensation seeking scores (ARR = .77, CI: .61-.97) and no conventional cigarette use (ARR = .48, CI: .37-.64) at baseline.

CONCLUSION

E-cigarette use is associated with a subsequent initiation of cannabis use. This association seems to be stronger for youth who have a lower risk for substance use in general. Future studies need to investigate whether this is only true for experimental or also more frequent cannabis use.

IMPLICATIONS

The study indicates a prospective association between e-cigarette use and initiation of cannabis experimentation independent of other risk factors. It suggests that e-cigarette use is more strongly associated with cannabis initiation for youth with a lower propensity to use substances (low sensation-seekers and non-smokers).

Electronic cigarette and cannabis use: results from the 2018 Maryland Youth Risk Behavior Survey

OBJECTIVE

To determine the relationship between lifetime e-cigarette use and current cannabis use among youth. Our analyses accounted for county variability, in addition to student-level covariates.

METHODS

This study examined responses from high school students on a state-level population survey, the 2018 Maryland Youth Risk Behavior Survey/Youth Tobacco Survey, a cross-sectional, complex survey sample. Of participating students, final analyses included an unweighted sample of 41,091 9th to 12th grade students who provided complete reports for measured variables. Analyses with survey weights were conducted between August 2019 and May 2020. A multivariable logistic regression was conducted to investigate the association between lifetime e-cigarette use and current (past 30-day) cannabis use, after controlling for county, lifetime cigarette use, current (past 30-day) alcohol use, emotional distress, and demographics.

RESULTS

Lifetime e-cigarette use significantly increased the odds of current cannabis use among Maryland high school students (aOR = 6.04; 95% CI 5.27, 6.93). Other significant risk factors for current cannabis use included lifetime cigarette use (aOR 2.23, 95% CI 1.86, 2.68) and current alcohol use (aOR 5.21, 95% CI 4.42, 6.14). Significantly higher odds of current cannabis use were also found among older high school students, males, non-Hispanic Blacks and students identifying as other race, and those reporting emotional distress.

CONCLUSIONS

Lifetime e-cigarette use among Maryland high school students is strongly associated with current cannabis use when including counties as a covariate. Non-significant county differences, however, suggest smaller geographical units may be required to control for variability. Efforts should focus on reducing youth e-cigarette use to decrease cannabis use. Maryland's recent implementation of Tobacco 21 and a ban on flavored e-cigarettes will be of interest for future evaluations.

Where There Is (No) Smoke, There Is Still Fire: a Review of Trends, Reasons for Use, Preferences and Harm Perceptions of Adolescent and Young Adult Electronic Cigarette Use

Purpose of the review

To review the current prevalence, trends, perceptions, and effects of e-cigarette or vaping product use associated lung injury (EVALI) on e-cigarette use among US adolescents and young adults.

Recent findings

COVID-19 diagnosis was more likely among the current/ever dual cigarette and e-cigarettes users, as well as ever e-cigarette only users. Additionally, the EVALI outbreak may have influenced harm perceptions, as daily nicotine vaping declined significantly from 2019 to 2020, and more youth and young adults perceived vaping as harmful.

Summary

The prevalence of e-cigarette use, specifically flavored use, remains high among adolescents and young adults, which is concerning due to the short-term and unknown long-term effects of e-cigarettes and their association with future cigarette and other substance use.

State Medical Marijuana Laws and Initiation of Cigarettes among Adolescents in the U.S., 1991-2015

Objective

Although cigarette use has declined among adolescents, marijuana use has increased in subgroups of this population. The association between medical marijuana laws (MMLs) and cigarette initiation among adolescents, however, needs further examination. We investigated the association between MMLs and age of cigarette initiation and stratified findings by gender, race/ethnicity, and state dispensary status.

Method

Data were from N=939,725 adolescents in 9th-12th grade living in 46 states who participated in the Youth Risk Behavior Surveillance System between 1991-2015. Participants were asked the age they first smoked a cigarette and other sociodemographic characteristics. States were categorized as MML states if they had legalized marijuana for medicinal purposes by 2015. We used a difference-in-difference methodology and logistic regressions to assess the relationship between MMLs and cigarette initiation.

Results

Our results indicate lower odds of initiating cigarettes, in every age group (8 years old or younger, 9-10, 11-12, 13-14, 15-16, 17 years old or older) in states with MMLs when compared to non-MML states. After stratification, we find lower odds of cigarette initiation in certain age groups by gender, race/ethnicity, and state dispensary status. We report no difference in state MML implementation and age of cigarette initiation among Hispanic adolescents in every age group, and Black adolescents 8 years or younger and 17 years or older.

Conclusions

Cigarette initiation has decreased among adolescents in MML states compared with those in non-MML states. Further research should evaluate how MMLs and recreational marijuana policies are associated with e-cigarette initiation and use.

Prevalence and modes of cannabis use among youth in Canada, England, and the US, 2017 to 2019

OBJECTIVE

Cannabis markets are evolving in terms of greater diversity and potency of products. The current study examined changes in cannabis use and modes of consumption among 16- to 19-year-olds in three markets with different regulatory frameworks: England, Canada, and the United States (US).

METHODS

Repeat cross-sectional online surveys were conducted in 2017, 2018, and 2019, with samples of 16- to 19-year-olds recruited from commercial panels in Canada (n = 11,779), England (n = 11,117), and the US (n = 11,869). Regression models examined changes in the prevalence of any cannabis use and use of seven modes of consumption, across the countries.

RESULTS

Cannabis use among youth was more prevalent among respondents in Canada and the US than in England in all years and increased to a greater extent between 2017 and 2019 (p < .001 for all contrasts). Among past 30-day cannabis consumers, the prevalence of vaping oils/liquids and the use of cannabis extracts (oil, wax and shatter) increased in all countries, and was significantly higher in Canada and US. For example, the prevalence of vaping oils/liquids increased from 24.2 % in 2017 to 52.1 % in 2019 among past 30-day cannabis consumers in the US (AOR = 3.46, 95 %CI = 2.57-4.66).

CONCLUSION

Prevalence is increasing for the most potent categories of cannabis products, particularly among youth in Canada and the US. Future research should examine the potential risks of these products and whether shifts in modes of cannabis reflect recent permissive changes to cannabis policy.

The effects of nicotine and cannabis co-use during adolescence and young adulthood on white matter cerebral blood flow estimates

RATIONALE

Co-use of cannabis and nicotine is common among adolescents/young adults and is associated with poorer psychological and physical outcomes, compared with single substance use. Little is known about the impact of co-use on the developing brain.

OBJECTIVES

Preliminary investigation of the effects of nicotine on white matter (WM) cerebral blood flow (CBF) in adolescents/young adults and its potential moderation by cannabis use.

METHODS

Adolescent/young adult (16-22 years old) nicotine and tobacco product users (NTP; N = 37) and non-nicotine users (non-NTP; N = 26) underwent a neuroimaging session comprised of anatomical, optimized pseudo-continuous arterial spin labeling, and diffusion tensor imaging scans. Groups were compared on whole-brain WM CBF estimates and their relation to past-year cannabis use. Follow-up analyses assessed correlations between identified CBF clusters and corresponding fractional anisotropy (FA) values.

RESULTS

Group by cannabis effects were observed in five clusters (voxel-wise alpha < 0.001, cluster-wise alpha < 0.05; ≥ 11 contiguous voxels): non-NTP exhibited positive correlations between CBF and cannabis use in all clusters, whereas no significant relationships were observed for NTP. Greater CBF extracted from one cluster (including portions of right superior longitudinal fasciculus) was associated with reduced FA for non-NTP group only.

CONCLUSIONS

This is the first investigation of WM health as indexed by CBF, and its association with FA, in adolescents/young adults with nicotine and/or cannabis use. Results suggest that cannabis use by itself may be related to increased CBF in WM fiber tracts demonstrating poorer structural intergrity, yet the occurrence of even infrequent NTP use (greater than once per month) appears to diminish this relationship.

Treatment Implications Associated with Cannabis and Tobacco Co-Use

PURPOSE OF THE REVIEW

The goal of this article is to summarize the treatment-focused literature on cannabis and tobacco co-use and the treatment implications of co-use. This review will focus on: 1) the impact of co-use on cessation outcomes, 2) compensatory use/substitution of the non-treated substance among co-users, and 3) treatment interventions to address co-use. This article will highlight the limitations to co-use captured in the literature and offer considerations and directives for co-use research and treatment moving forward.

RECENT FINDINGS

The degree to which co-use affects cessation for a single, targeted substance remains in question, as the literature is largely mixed. Cannabis treatment trials are better equipped to answer these questions given that they do not typically exclude tobacco users. While the relationship between tobacco use and poorer cannabis outcomes appears to have some evidence, the reverse relationship (cannabis use affecting tobacco outcomes) is not consistently supported.

SUMMARY

The co-use of cannabis and tobacco and its impact on single substance cessation and/or compensatory substance use during cessation is generally overlooked in treatment trials, while interventions to address both substances are rare. Capturing co-use adds burden for researchers, clinicians, and participants, but is warranted given the prevalence of co-use and a rapidly changing cannabis and tobacco regulatory environment, which may further complicate co-occurring substance use. Co-users are a heterogeneous population; trials focused on co-users, in addition to better data capture and consistent terminology, will aid in an understanding of nuanced patterns of co-use critical to inform treatment interventions.

Systematic Review of Electronic Cigarette Use (Vaping) and Mental Health Comorbidity Among Adolescents and Young Adults

Introduction

The prevalence of electronic cigarette (EC) use has risen dramatically among adolescents and young adults (AYA, ages 12–26) over the past decade. Despite extensive established relationships between combustible cigarette use and mental health problems, the mental health comorbidities of EC use remain unclear.

Aims and Methods

To provide a systematic review of existing literature on mental health comorbidities of EC use among AYA. Database searches using search terms related to EC, AYA, and mental health identified 1168 unique articles, 87 of which prompted full-text screening. Multiple authors extracted data, applied the Effective Public Health Practice Project Quality Assessment Tool to evaluate the evidence, and synthesized findings.

Results

Forty articles met eligibility criteria (n = 24 predominantly adolescent and 16 predominantly young adult). Analyses yielded three main categories of focus: internalizing disorders (including depression, anxiety, suicidality, eating disorders, post-traumatic stress disorder), externalizing disorders (attention-deficit/hyperactivity disorder and conduct disorder), and transdiagnostic concepts (impulsivity and perceived stress). Significant methodological limitations were noted.

Conclusions

Youth EC use is associated with greater mental health problems (compared with nonuse) across several domains, particularly among adolescents. Because many existing studies are cross-sectional, directionality remains uncertain. Well-designed longitudinal studies to investigate long-term mental health sequelae of EC use remain needed.

Implications

Forty recent studies demonstrate a variety of mental health comorbidities with AYA EC use, particularly among adolescents. Mental health comorbidities of EC use generally parallel those of combustible cigarette use, with a few exceptions. Future EC prevention and treatment strategies may be enhanced by addressing mental health.

Digital health for assessment and intervention targeting tobacco and cannabis co-use

Purpose of review

This article aims to summarize current research on digital health for assessment and intervention targeting tobacco and cannabis co-use and to answer the following questions: Which digital tools have been used? Which populations have been targeted? And what are implications for future research?

Recent findings

Ecological Momentary Assessment (EMA) via text messages or interactive voice response calls has been used to capture co-use patterns within a time window or co-administration of both substances via blunts among young adults. Feasibility of multicomponent interventions targeting dual cessation of both substances among adult co-users with cannabis use disorder, delivered via smartphone apps, online, and computer modules has been demonstrated.

Summary

Digital tools, particularly those using EMAs and mobile sensors, should be expanded to assess co-use of emerging tobacco and cannabis products. Digital cessation interventions should be tailored to different groups of co-users and address specific mechanisms underlying different co-use patterns.