Unknown population-level harms of cannabis and tobacco co-use: if you don't measure it, you can't manage it

Nicotine and cannabis routes of administration and dual use among U.S. young adults who identify as Hispanic, non-Hispanic Black, and non-Hispanic White

Background

Use of cannabis and nicotine is at record levels among young adults, and health consequences vary by route of administration. However, there is a paucity of research characterizing use of both substances, especially among individuals of racial/ethnic minoritized identities.

Method

Participants (N = 1,032; age 18-25 years) completed a cross-sectional survey administered through an online panel in 2021 in eight U.S. states where cannabis was legal for both recreational and medical use and eight states where cannabis was not legal for medical or recreational purposes. Sampling was stratified by race/ethnicity (Hispanic, non-Hispanic Black, non-Hispanic White) and gender (male, female). Survey weighting was based on state-level gender and race/ethnicity data in the 2021 U.S. Census Bureau.

Results

Over one third (37.9%) of respondents reported current use of both cannabis and tobacco, more than double the proportion using tobacco (12.1%) or cannabis (4.1%) only. Vaporization was the most common method for using nicotine (40.2%). Disposable nicotine vape products were used more than any other method (27.1%). Smoking was the most common route of administration for cannabis (35.7%). Simultaneous use of tobacco and cannabis was common (27.0%) overall and greater among those who identify as non-Hispanic Black than non-Hispanic White. There were few differences in product use by gender or state legality.

Discussion

Dual cannabis and tobacco use is prevalent among young adults. Given the dynamic regulatory landscape, continued monitoring of specific cannabis formulations and tobacco products is recommended. Trends in simultaneous use of cannabis and tobacco and associated adverse effects warrant continued assessment.

Urgent need for treatment addressing co-use of tobacco and cannabis: An updated review and considerations for future interventions

BACKGROUND

There are no clinical practice guidelines addressing the treatment of tobacco-cannabis co-use and a dearth of studies to inform treatment for co-use. This narrative review aims to (1) summarize promising intervention components used in published co-use treatment studies, (2) describe key gaps and emerging issues in co-use, and (3) provide recommendations and considerations in the development and evaluation of co-use interventions.

METHODS

We conducted a literature search in June 2024 across several databases to update previous reviews on tobacco-cannabis co-use treatment. We found 9 published intervention studies that specifically addressed treatment for both substances. Data from these studies were manually extracted and summarized.

RESULTS

Most of the 9 included studies (1) focused on acceptability and/or feasibility, (2) provided both psychosocial/behavioral and pharmacotherapy intervention components, (3) were conducted in adults, and (4) were delivered in-person, with some having digital asynchronous components, for a 5-to-12-week duration. The most common psychosocial/behavioral strategies used were Cognitive Behavioral Therapy, Motivational Interviewing, and Contingency Management; while the most common pharmacotherapy was Nicotine Replacement Therapy. There was no evidence of compensatory use of tobacco or cannabis when providing simultaneous treatment for both substances.

CONCLUSIONS

The literature to date provides support for well-integrated multi-component interventions of psychosocial/behavioral and pharmacotherapy strategies for co-use treatment. This review reinforces an urgent need for treatments targeting tobacco and cannabis co-use. Future interventions should address key gaps, including co-use of vaporized products among youth and young adults, tailored interventions for priority populations, and digital applications to increase reach and advance health equity.

Understanding Cannabis-Related Information Needs: An Analysis of Inquiries to the National Cancer Institute's Cancer Information Service

Purpose: Given increased cannabis use for medical and nonmedical purposes alike, there is growing public interest related to the potential risks and benefits of cannabis use, particularly related to cancer. The purpose of this descriptive study was to analyze cannabis inquiries to the National Cancer Institute's Cancer Information Service (CIS). Materials and Methods: From September 2018 to June 2023, 190,070 noncannabis and 425 cannabis inquiries were documented by the CIS. Cannabis inquiries were delineated into two categories: nonmedical cannabis (NMC, n=240) or medical cannabis (MC, n=185). Chi-square tests were performed to determine differences between noncannabis and cannabis inquiries and descriptive analyses were used to identify patterns within cannabis-specific inquiries. Results: Statistically significant differences between noncannabis and cannabis inquiries were observed. In addition, there were variations in MC and NMC inquiries. For example, 73% of MC inquiries originated from cancer survivors and caregivers, whereas almost half of NMC inquiries (48%) were from individuals identifying as tobacco users. MC and NMC inquiries also differed by CIS access channel (e.g., instant chat, telephone), language used (English vs. Spanish), discussions of cancer continuum phases and cancer sites, and referrals provided to individuals for additional information and resources. Conclusion: Cannabis-related information needs of the public-as documented by the CIS-varied by several factors. Health information sources such as the CIS can help address cannabis-related questions and concerns, while noting differences in who is inquiring, how, and why.

Dual-Vaping of Nicotine and Cannabis Among Adults Who Currently Use Tobacco Products in Five New England States

INTRODUCTION

Current measures of vaping behaviors in the U.S. do not distinguish what substances participants are vaping and to what extent they are dual-vaping nicotine and cannabis. This study describes the use of new survey questions that more specifically ask whether participants who vape are vaping nicotine, cannabis, cannabidiol (CBD), or another substance.

AIMS AND METHODS

Adults, who reported any past 30-day tobacco use, from five New England states participated in an online survey from April 2021 to July 2022. Participants who vaped were asked, "Have you used any of the following vape substances in the past 30 days?" with the possible responses of nicotine, cannabis, CBD, other, and "don't know." Dual use of both nicotine and cannabis was defined as the vaping of both nicotine and cannabis and/or CBD in the past 30 days, operationalized as a dichotomous outcome. Data were collected in monthly, repeated cross-sectional waves. Multinomial logistic regression was used to examine correlates of dual-vaping.

RESULTS

The analytic sample included 1547 adults who reported past 30-day tobacco use (mean age 42.9 years, 62.8% female, 85.4% White, 48.5% income of less than $50 000). Over one-quarter (26.1%) reported dual-vaping in the past 30 days. Identifying as male (p = .002) and self-rated anxiety (p = .043) were associated with a higher odds of dual-vaping.

CONCLUSIONS

Our findings show that a sizable proportion of a sample of New England adults who have used tobacco in the past 30 days are dual-vaping nicotine and cannabis. Adequate survey measures for assessing the vaping of multiple substances can help in better screening and characterization of health behaviors around dual-use.

IMPLICATIONS

This study addresses a key gap in adequate survey measures for assessing vaping of multiple substances. We found that among adults with past 30-day tobacco use, dual-vaping was prevalent and associated with different correlates, such as self-reported anxiety and education level, compared to sole-vaping of nicotine or cannabis. Our findings may help in characterizing and targeting future population-level surveillance and intervention efforts for multiple substance use behaviors.

Tobacco-cannabis co-use among cancer patients and survivors: findings from 2 US cancer centers

BACKGROUND

Cannabis use is prevalent among cancer patients and survivors and may provide some therapeutic benefits for this population. However, benefits may be attenuated when cannabis is co-used with tobacco, which is associated with more severe tobacco and cannabis use and adverse outcomes in noncancer populations. We compared cannabis use, primary mode of use, and therapeutic and/or nontherapeutic use among 3 groups of patients and survivors based on cigarette smoking status.

METHODS

Survey data was collected from patients and survivors with cancer (n = 1732) at 2 US National Cancer Institute-designated cancer centers in states with varying cannabis regulatory policy. Prevalence of cannabis use (prior to diagnosis, after diagnosis, before treatment, after treatment), primary mode of use, and therapeutic and/or nontherapeutic use were assessed by cigarette smoking status (current, former, never) within and across centers using weighted bivariate analyses and multivariable logistic regression, controlling for demographic and clinical variables.

RESULTS

Current cigarette use was associated with greater rates of cannabis use prior to diagnosis, after diagnosis, during treatment, and after treatment within each center (all P < .001) and in pooled analyses across centers (all P < .001). Primary mode of use, knowledge of cannabis products, and therapeutic and/or nontherapeutic use also statistically differed by tobacco status and study site.

CONCLUSIONS

Results illustrate the importance of conducting assessments for both tobacco and cannabis use among cancer patients during and after cancer treatment, regardless of the cannabis regulatory environment. Given previous data indicating harms from co-use and continued tobacco use during cancer treatment, this issue introduces new priorities for cancer care delivery and research.

Tobacco Quitline Callers Who Use Cannabis and Their Likelihood of Quitting Cigarette Smoking

INTRODUCTION

Cigarette smoking continues to decline in the U.S., but cannabis use is increasing. Many people who smoke cigarettes also use cannabis. This study examines the characteristics of persons who co-use and those who do not co-use and the likelihood of quitting cigarettes for callers to Kick It California, a large state tobacco quitline.

METHODS

Data were examined from Kick It California callers from January 2020 through December 2023 (N=45,151), including those from a subgroup randomly sampled and reached for evaluation at 7 months after quitline enrollment (n=3,545). The rate of cigarette smoking cessation at 7 months after enrollment for people who co-use cannabis was compared with that for people who do not. Analyses started in 2023 and concluded in January 2024.

RESULTS

More than a quarter (27.2%) of Kick It California callers co-used cannabis. They were more likely to be male, to be younger, and to have a mental health condition than those who did not. Those who co-use cannabis and those who do not have similar rates of receiving quitline counseling or using Food and Drug Administration-approved cessation aids. Controlled for effects of personal characteristics and use of smoking-cessation services, people who co-use cannabis were less likely to quit cigarette smoking 7 months after enrollment (23.2% vs 28.9%; p<0.001). Among those who co-use, 42.9% intended to quit using cannabis in the next 30 days.

CONCLUSIONS

A substantial percentage of tobacco quitline callers use cannabis. Those who do co-use quit cigarette smoking at a lower rate than those who do not. Over 40% of people who co-use reported intention to quit cannabis, making tobacco quitlines a rich environment to learn about people who co-use and develop strategies for intervention.

Predicting Time to Return to Cannabis Use After a Cessation Attempt: Impact of Cumulated Exposure to Nicotine-Containing Products

Objective: Cannabis is frequently co-used with tobacco/nicotine products, especially among young adults. Little is known about the effects of this co-use on cannabis cessation outcomes. Within a sample of young adults using cannabis frequently (current use of ≥5 days/week in the past 3 months), this study aimed to (a) document sources of exposure to tobacco/nicotine products, whether used simultaneously with cannabis or on different occasions, (b) examine if the level of cumulated exposure to tobacco/nicotine (self-reported or from biochemical testing) could predict time to cannabis lapse during a cannabis abstinence period, and (c) explore the relationship between nicotine/tobacco exposure and time to cannabis lapse according to tobacco cigarette smoking status. Method: Urine cotinine measures and self-reported data on use of different tobacco/nicotine products, collected from 32 participants (aged 19 to 23), were analyzed to predict time to lapse during a 2-week period of attempted abstinence from cannabis, controlling for cannabis dependence and sex. Results: Half of participants (56.3%) used at least one tobacco/nicotine product. Higher urine cotinine, representing higher cumulated tobacco/nicotine exposure, was related to a higher risk of lapsing (Hazard Ratio [HR] = 1.64; 95%CI [1.04, 2.58]). The risk of lapsing was even higher ([HR] = 3.46; 95%CI [1.17, 10.25]) among heavily tobacco/nicotine exposed (>600 ng/mL, urine cotinine) participants than among unexposed (<50 ng/mL) or lightly/moderately exposed (50-600 ng/mL) participants. Among those smoking cigarettes (solely or in combination with other products), there was no relation between cotinine level and time to lapse, likely due to a reduced variability in abstinence probability and a high likelihood of lapse observed for higher cotinine levels, mainly achieved by cigarette use. Conclusions: With a rapidly changing landscape of tobacco/nicotine use, our results underscore the need to consider all sources of tobacco/nicotine exposure to fully understand the specific and cumulative contributions of tobacco/nicotine to cannabis cessation outcomes.

Classification of patterns of tobacco and cannabis co-use based on temporal proximity: A qualitative study among young adults

PURPOSE

Co-use of tobacco and cannabis is a common and complex behavior. The lack of harmonized measures of co-use yields confusion and inconsistencies in synthesizing evidence about the health effects of co-use. We aimed to classify co-use patterns based on temporal proximity and describe preferred products and motives for each pattern in order to improve co-use surveillance.

METHODS

We conducted semi-structured interviews in a sample of 34 young adults (Mage = 22.8 years, 32.4 % female) during 2017-2019 in California, USA. We employed a qualitative thematic analysis to identify timing, reasons, and contexts for tobacco and cannabis co-use and classify co-use patterns.

RESULTS

Four emergent patterns of co-use with increasing temporal proximity between tobacco use and cannabis use were: Same-month different-day co-use (Pattern 1); Same-day different-occasion co-use (Pattern 2); Same-occasion sequential co-use (Pattern 3); and Same-occasion simultaneous co-use (Pattern 4). Participants used various product combinations within each pattern. Similar motives for all patterns were socialization, product availability, and coping with stress/anxiety. Unique motive for temporally distant patterns (Patterns 1 and 2) was seeking substance-specific effects (e.g., stimulant effect from nicotine, relaxation effects from cannabis), while unique motives for temporally close patterns (Patterns 3 and 4) were seeking combined effects from both substances (e.g., more intense psychoactive effects, mitigating cannabis adverse effects) and behavioral trigger (e.g., cannabis use triggers tobacco use).

CONCLUSIONS

Our classification of co-use patterns can facilitate consistency for measuring co-use and assessing its health impacts. Future research should also measure product types and motives for different patterns to inform intervention efforts.

Quantity of cigarettes smoked when co-used with alcohol and cannabis: Consideration of different definitions of co-use based on daily diary data

INTRODUCTION

Cigarettes are frequently co-used with alcohol and cannabis. However, definitions of co-use vary and the extent to which cigarette use changes on days with different patterns of co-use is unclear. We compared the number of cigarettes smoked on different days based on co-use patterns of cigarettes and alcohol or cannabis.

METHODS

This study analyzed 2408 smoking days collected in a 30-day smartphone-based daily diary study among 146 young adults (aged 18-26) with an oversample from sexual minority groups. Two separate multilevel models were estimated: one for cigarette and alcohol co-use and the other for cigarette and cannabis co-use. Both models examined day-level associations between the number of cigarettes smoked and 3 different types of days (smoking-only days, same-occasion co-use days, different-occasion co-use days), controlling for demographic characteristics.

RESULTS

More cigarettes were smoked on same-occasion co-use days compared to cigarette-smoking-only days for both alcohol (b=1.474, SE=0.136, t=10.8, p<.001) and cannabis (b=0.822, SE=0.209, t=3.9, p<.001). There were no significant differences in cigarettes smoked on days with co-use on the same day, but on different occasions, compared to days with smoking only.

CONCLUSIONS

Compared to days with cigarette smoking only, more cigarettes are smoked on days when cigarettes are co-used with alcohol or cannabis on the same occasion, while the same is not true for days with co-use on different occasions. Conflating different definitions of co-use may impact findings on associations between co-use and smoking behavior.

Marijuana and E-cigarette Initiation Among Adolescents: A Survival Analysis

PURPOSE

Prior literature suggests marijuana and e-cigarette initiation among adolescents is surpassing combustible cigarette uptake. Marijuana and nicotine co-use is also a concern as these products grow in popularity. Initiation trajectories for marijuana and e-cigarette products are not well understood, let alone how the use of one product may impact initiation susceptibility for the other.

METHODS

We used national longitudinal data from the Population Assessment of Tobacco and Health study from 2013 to 2018. Eighth graders in Wave 1 made up the analytic sample (N = 2,270). We employed discrete time survival analyses to determine the likelihood of initiating marijuana and e-cigarettes between Waves 2 and 5. We used survival analyses to estimate the relationships between prior cigarette and marijuana use and subsequent e-cigarette initiation, as well as prior cigarette and e-cigarette use and subsequent marijuana initiation.

RESULTS

Previous marijuana initiation was associated with later e-cigarette initiation (odds ratio = 6.88, 95% confidence interval [4.89, 9.67]). Previous e-cigarette initiation was associated with later marijuana initiation (odds ratio = 9.28, 95% confidence interval [6.86, 12.56]). By wave 5, adolescents were more than 42% likely to initiate marijuana and e-cigarettes.

DISCUSSION

Susceptibility to marijuana and e-cigarette products starts as early as eighth grade and increases over time. The use of one product is significantly related to later initiation for the other. Rather than addressing marijuana and nicotine as separate concerns, interventions may benefit by recognizing the closely related nature of these products.

Perceived Effectiveness of Cigar Warnings in Discouraging Blunt Use

INTRODUCTION

Many people remove the tobacco leaf from cigars and replace it with cannabis (ie, blunts), but few studies have examined whether messages about the risks of cigars, like warnings on cigar packages, can affect blunt use.

METHODS

Participants were 438 U.S. adults who reported past 30-day cigar use and ever blunt use, recruited from a probability-based national panel to take an online survey. In a 2 × 2 experiment with a between-subjects design, we manipulated two cigar warning characteristics: (1) warning type: text-only versus pictorial (ie, text + image) and (2) warning size: 30% (smaller) versus 50% (larger) of the product package. Participants then viewed six different warnings on a fictious cigarillo package, within their randomly assigned condition. After evaluating all stimuli, participants were asked the extent to which the warnings discouraged them from wanting to use cigars to smoke cannabis (ie, blunt perceived warning effectiveness). Response options ranged from "not at all" (1) to "a great deal" (5).

RESULTS

We observed no main effects of warning type or size on blunt perceived warning effectiveness. However, a significant interaction existed between the two experimental manipulations (p = .009). Whereas adding images made no difference to blunt perceived warning effectiveness when warnings were smaller (simple effect: -0.22, p = .28), images mattered for larger warnings. Specifically, adding images increased blunt perceived warning effectiveness when warnings were 50% of the product package (simple effect: 0.52, p = .008).

CONCLUSIONS

This experiment provides preliminary evidence that larger pictorial cigar warnings may discourage blunt use relative to larger but text-only warnings.

IMPLICATIONS

Blunts, which are hollowed out cigars with tobacco leaf wrappers that are filled with cannabis leaf, are one of the most common ways in which tobacco and cannabis are used simultaneously, yet few studies have examined whether messages about the risks of cigars can affect blunt use. We conducted an online experiment concerning the perceived effectiveness of cigar warnings among people who use blunts recruited from a probability-based panel. Results provide novel, preliminary evidence that larger pictorial cigar warnings may discourage blunt use, relative to larger but text-only warnings. More research evaluating cigar warnings on blunt use is needed.

Genetic and shared environmental factors explain the association between adolescent polysubstance use and high school noncompletion

OBJECTIVE

Examine the nature of the relationship between adolescent polysubstance use and high school noncompletion.

METHOD

Among a sample of 9,579 adult Australian twins (58.63% female, Mage = 30.59), we examined the association between the number of substances used in adolescence and high school noncompletion within a discordant twin design and bivariate twin analysis.

RESULTS

In individual-level models controlling for parental education, conduct disorder symptoms, childhood major depression, sex, zygosity, and cohort, each additional substance used in adolescence was associated with a 30% increase in the odds of high school noncompletion (OR = 1.30 [1.18, 1.42]). Discordant twin models found that the potentially causal effect of adolescent use on high school noncompletion was nonsignificant (OR = 1.19 [0.96, 1.47]). Follow-up bivariate twin models suggested genetic (35.4%, 95% CI [24.5%, 48.7%]) and shared environmental influences (27.8%, 95% CI [12.7%, 35.1%]) each contributed to the covariation in adolescent polysubstance use and early school dropout.

CONCLUSIONS

The association between polysubstance use and early school dropout was largely accounted for by genetic and shared environmental factors, with nonsignificant evidence for a potentially causal association. Future research should examine whether underlying shared risk factors reflect a general propensity for addiction, a broader externalizing liability, or a combination of the two. More evidence using finer measurement of substance use is needed to rule out a causal association between adolescent polysubstance use and high school noncompletion. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The effects of nicotine use during adolescence and young adulthood on gray matter cerebral blood flow estimates

Nicotine and tobacco product (NTP) use remains prevalent in adolescence/young adulthood. The effects of NTPs on markers of brain health during this vulnerable neurodevelopmental period remain largely unknown. This report investigates associations between NTP use and gray matter cerebral blood flow (CBF) in adolescents/young adults. Adolescent/young adult (16-22 years-old) nicotine users (NTP; N = 99; 40 women) and non-users (non-NTP; N = 95; 56 women) underwent neuroimaging sessions including anatomical and optimized pseudo-continuous arterial spin labeling scans. Groups were compared on whole-brain gray matter CBF estimates and their relation to age and sex at birth. Follow-up analyses assessed correlations between identified CBF clusters and NTP recency and dependence measures. Controlling for age and sex, the NTP vs. non-NTP contrast revealed a single cluster that survived thresholding which included portions of bilateral precuneus (voxel-wise alpha < 0.001, cluster-wise alpha < 0.05; ≥7 contiguous voxels). An interaction between NTP group contrast and age was observed in two clusters including regions of the left posterior cingulate (PCC)/lingual gyrus and right anterior cingulate cortex (ACC): non-NTP exhibited positive correlations between CBF and age in these clusters, whereas NTP exhibited negative correlations between CBF and age. Lower CBF from these three clusters correlated with urine cotinine (rs=-0.21 - - 0.16; ps < 0.04) and nicotine dependence severity (rs=-0.16 - - 0.13; ps < 0.07). This is the first investigation of gray matter CBF in adolescent/young adult users of NTPs. The results are consistent with literature on adults showing age- and nicotine-related declines in CBF and identify the precuneus/PCC and ACC as potential key regions subserving the development of nicotine dependence.

Cannabis use disorder and adverse cardiovascular outcomes: A population-based retrospective cohort analysis of adults from Alberta, Canada

AIM

To measure the association between cannabis use disorder (CUD) and adverse cardiovascular disease (CVD) outcomes.

DESIGN AND SETTING

We conducted a matched, population-based retrospective cohort study involving five linked administrative health databases from Alberta, Canada.

PARTICIPANTS

We identified participants with CUD diagnosis codes and matched them to participants without CUD codes by gender, year of birth and time of presentation to the health system. We included 29 764 pairs (n = 59 528 individuals in total).

MEASUREMENTS

CVD events were defined by at least one incident diagnostic code within the study period (1 January 2012-31 December 2019). Covariates included comorbidity, socio-economic status, prescription medication use and health service use. Using mortality-censored Poisson regression models, we computed survival analyses for time to incident CVD stratified by CUD status. In addition, we calculated crude and stratified risk ratios (RRs) across various covariates using the Mantel-Haenszel technique.

FINDINGS

The overall prevalence of documented CUD was 0.8%. Approximately 2.4% and 1.5% of participants in the CUD and unexposed groups experienced an incident adverse CVD event (RR = 1.57; 95% confidence interval = 1.40-1.77). CUD was significantly associated with reduced time to incident CVD event. Individuals who appeared to have greater RRs for incident CVD were those without mental health comorbidity, who had not used health-care services in the previous 6 months, who were not on prescription medications and who did not have comorbid conditions.

CONCLUSIONS

Canadian adults with cannabis use disorder appear to have an approximately 60% higher risk of experiencing incident adverse cardiovascular disease events than those without cannabis use disorder.

How much cannabis is used in a joint in Australia? An experimental investigation into use by potency and frequency

INTRODUCTION

Cannabis use is highly prevalent in Australia, yet current survey metrics measure tetrahydrocannabinol (THC) exposure with limited accuracy. Often survey items measure cannabis quantity by assuming specific modes of use (i.e., 'how many joints do you use?'), which fail to capture variations in cannabis use and the diverse modes of use (e.g., joints, cones, spliffs). This study investigated how much cannabis is used in these modes of administration in an Australian sample.

METHODS

Participants (N = 31, Mage  = 25.77; 51% university students) completed the Roll a Joint Paradigm in which they rolled joints, spliffs and packed cones as they would typically, using oregano as 'cannabis.' Participants then prepared each again but with cannabis of higher or lower potency.

RESULTS

The amount of cannabis used across different modes of administration was variable: joints (range 0.10-1.25 g), spliffs (range 0.12-1.21 g) and cones (range 0.03-0.41 g). Participants who used cannabis daily rolled three times the amount of cannabis into a joint.

DISCUSSION AND CONCLUSIONS

The amount of cannabis used in common modes of administration may be highly variable. Daily use may be associated using larger quantities of cannabis. Titration attempts based on potency were not proportional or consistent across modes of administration. The results indicate people may adjust the quantity of cannabis based on perceived potency, however, not proportional to THC concentration. Inconsistency in the amount of cannabis used based on potency and within different modes of administration may represent a problem for self-report metrics which ask participants to report cannabis use in joints.

Prevalence and correlates of past 30-day dual-vaping of nicotine and cannabis among adolescents in five New England states

SIGNIFICANCE

Adolescent vaping behavior includes vaping of multiple substances, including both nicotine and cannabis (dual-vaping). This study describes the prevalence and the sociodemographic correlates of past 30-day dual-vaping.

METHODS

We recruited adolescents ages 13-17 from five New England states (Massachusetts, Connecticut, Rhode Island, Vermont, New Hampshire) through the Prodege online survey panel from April 2021 to August 2022. Dual-vaping was defined as vaping both nicotine and cannabis (THC and/or CBD) in the past 30-days. We analyzed the prevalence of sole-nicotine, sole-cannabis, and dual-vaping of nicotine and cannabis and used multinomial logistic regression to examine associations between sociodemographic factors and sole- and dual-vaping of nicotine and cannabis.

RESULTS

The analytic sample included 2013 observations from 1858 participants (mean age 15.1 years, 46.2% female, 74.1% White, 82.2% heterosexual). Among these observations, 5.6% reported past 30-day sole-nicotine vaping, 5.5% reported sole-cannabis vaping, and 7.3% had dual-vaped. Correlates for higher odds of past 30-day dual-vaping included total social media sites used and household tobacco use, in contrast with sole-cannabis vaping, which included older age and self-reported depression (all p's <0.05).

DISCUSSION

Adolescent past 30-day dual-vaping of nicotine and cannabis was more prevalent than past 30-day sole-vaping of either nicotine or cannabis alone. Future studies should continue to collect detailed data on the type of substances, besides nicotine, that adolescents are vaping.

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

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

What Substances Are Adolescents Vaping? Estimating Nicotine-Specific and Cannabis-Specific Vaping from US National Youth Surveys

BACKGROUND

Youth use of electronic cigarettes ("e-cigarettes") is an ongoing concern. Vaping is usually assumed to be of nicotine, but survey responses may also include vaping of non-nicotine substances (particularly cannabis), which can impose different risks. The current study quantifies the proportions of nicotine-specific and cannabis-specific vaping among adolescents.

METHODS

Data from the Monitoring the Future (MTF) 2021 survey were analyzed with respect to the substance vaped: nicotine, cannabis, or flavoring only. Past-30-day (P30D) nicotine-specific vaping (exclusively, or also having vaped other substances) and cannabis-specific vaping were calculated. Results were also broken down by grade level, cigarette smoking history (current, former, or never), and frequency of e-cigarette use (<20 vs. 20+ days in P30D).

RESULTS

Among 4706 P30D e-cigarette users, 84.2% vaped nicotine; the remaining 15.8% reported not vaping any nicotine in P30D. Cannabis vaping was reported by 48.4% of P30D vapers. Vaping both nicotine and cannabis in P30D was more common in current and former smokers than in never-smokers, and in frequent vapers (of any substance). Conversely, never-smokers were more commonly vaping cannabis but not nicotine, compared to current and former smokers. Supplementary NYTS 2022 analyses were consistent with these findings.

CONCLUSIONS

A notable proportion of self-reported P30D vapers reported not vaping nicotine; nearly half vaped cannabis. Capturing the variety of substances used in vaping devices is imperative for accurate public health surveillance of both nicotine and cannabis vaping among US adolescents, considering their different respective harms and regulatory frameworks.

Assessing use of inhalable nicotine products within complex markets: the dilemma of heated tobacco products

The introduction of electronic inhalable products, such as nicotine vaping products (NVPs) and heated tobacco products (HTPs), has further diversified the nicotine market landscape. This poses unique challenges in measuring self-reported nicotine use behaviours, which have been the hallmark of tobacco surveillance systems. This paper raises concerns of potential measurement error for electronic inhalable product use in surveys due to similarities in product design between NVPs and HTPs, as well as changing trends in cannabis administration. We identify several strategies for addressing this issue (eg, including descriptive preambles in surveys that differentiate product classes from one another; incorporating survey questions that probe beyond an initial question regarding product use). In the absence of comprehensive validation studies, caution is warranted when interpreting survey results that rely on self-reported HTP use.

Understanding the complexity, patterns, and correlates of alcohol and other substance use among young people seeking help for mental ill-health

PURPOSE

Use of alcohol and other substances is a multifaceted issue impacting young people across multiple life domains. This paper aims to elucidate patterns of substance use and associated demographic and clinical factors among young people seeking treatment for their mental health.

METHODS

Young people (12-25 years old) were recruited from five youth-specific primary mental health ("headspace") services in Australia. Self-reported substance use and harms in the past 3 months were measured using WHO-ASSIST. Network analyses were conducted to evaluate interrelationships between use and harms associated with different substances. Subgroups were then identified based on whether participants reported using high centrality substances, and associated demographic and clinical factors were assessed with multinomial logistic regression.

RESULTS

1107 youth participated. 70% reported use of at least one substance in the past 3 months, with around 30% of those reporting related health, social, legal or financial problems. Network analysis highlighted substantial interconnections between use and harm indicators for all substances, with amphetamine-type stimulants (ATS) and cannabis being high central substances. Higher levels of substance use and harms were reported in subgroups with ATS or cannabis use and different risk factors were associated with these subgroups.

CONCLUSIONS

Findings highlight the importance of screening for substance use in youth primary mental healthcare settings, offering a key opportunity for early intervention. Clinicians should be aware of the inner connections of use and harms of different drugs and the role of cannabis and amphetamine use as a marker for more substance use profiles.

Cannabinoids for Substance Use Disorder Treatment: What Does the Current Evidence Say?

Background: The prevalence of Substance Use Disorder (SUD) is increasing along with the need to develop approaches to reduce the harm associated with substance use, including investigating alternatives such as cannabinoids, which show promising results, although the current evidence is limited. This scoping review focuses on the limitations and potentials of cannabinoid-based treatments for SUDs. Methods: We examined between-subject randomized controlled trials (RCTs) investigating the use of CBD and THC as pharmacological treatment for SUDs in adults, with the procedures attending the expectations of the Preferred Reporting Items for Scoping reviews and Meta-Analyses (PRISMA) for Scoping Reviews guidelines and assessed risk of bias using the Cochrane Risk of Bias Assessment Tool 2. Results: Ten RCTs were included, with six demonstrating low risk of bias, and positive results were found for treating Cannabis Use Disorder, while contradictory results were found for Opioid Use Disorder, and inconclusive results for treating Cocaine Use Disorder. Conclusions: CBD and THC demonstrate potential for treating some SUDs, but evidence is limited. Robust RCTs with larger samples and longer follow-up periods are necessary to assess carefully developed outcomes for different SUD patients. New cannabinoid-based medications and scientific-based policies may advance SUD treatment. A comprehensive approach to treatment and careful methodological choices may benefit patients with SUD.

Flavored Cannabis Use and Cannabis-Tobacco Co-use: Patterns In U.S. States With Legalized Nonmedical Adult Use

INTRODUCTION

Little is known about inhaled flavored cannabis use. This study aimed to investigate the prevalence and patterns of flavored cannabis use and cannabis-tobacco co-use.

METHODS

This study surveyed adult past 30-day cannabis users in U.S. states and districts that have legalized cannabis for nonmedical/adult use (n=9) (November 2018; n=2,978). By product/behavior (any cannabis, cannabis extract vaporizers, mixed cannabis-nicotine vaporizers, blunts, chasing), the association between flavored (versus non-flavored) use and sociodemographic characteristics, cannabis use disorder symptoms, and tobacco use was estimated using weighted multivariable logistic regression in January 2022.

RESULTS

Almost half of adult cannabis users reported using at least one flavored cannabis product (46.5%). Flavored cannabis use was more likely among respondents who were female (AOR=1.2, CI=1.0, 1.4), were Black (ref: White; AOR=2.2, CI=1.5, 3.1), were Hispanic/Latino/a/x (ref: White; AOR=1.6, CI=1.2, 1.9), had cannabis use disorder symptoms (AOR=2.0, CI=1.6, 2.4), or were currently using tobacco (AOR=2.4, CI=2.1, 2.9). Use was less likely among middle-aged/older adults (ref: ages 21-34 vs 35-49 years; AOR=0.6, CI=0.5, 0.7).

CONCLUSIONS

Observed differences in flavored cannabis use are concerning if flavors raise appeal or dependence. Integrating flavored cannabis and tobacco research and practice is warranted.

Associations between tobacco and cannabis use and anxiety and depression among adults in the United States: Findings from the COVID-19 citizen science study

BACKGROUND

Little is known about whether people who use both tobacco and cannabis (co-use) are more or less likely to have mental health disorders than single substance users or non-users. We aimed to examine associations between use of tobacco and/or cannabis with anxiety and depression.

METHODS

We analyzed data from the COVID-19 Citizen Science Study, a digital cohort study, collected via online surveys during 2020-2022 from a convenience sample of 53,843 US adults (≥ 18 years old) nationwide. Past 30-day use of tobacco and cannabis was self-reported at baseline and categorized into four exclusive patterns: tobacco-only use, cannabis-only use, co-use of both substances, and non-use. Anxiety and depression were repeatedly measured in monthly surveys. To account for multiple assessments of mental health outcomes within a participant, we used Generalized Estimating Equations to examine associations between the patterns of tobacco and cannabis use with each outcome.

RESULTS

In the total sample (mean age 51.0 years old, 67.9% female), 4.9% reported tobacco-only use, 6.9% cannabis-only use, 1.6% co-use, and 86.6% non-use. Proportions of reporting anxiety and depression were highest for the co-use group (26.5% and 28.3%, respectively) and lowest for the non-use group (10.6% and 11.2%, respectively). Compared to non-use, the adjusted odds of mental health disorders were highest for co-use (Anxiety: OR = 1.89, 95%CI = 1.64-2.18; Depression: OR = 1.77, 95%CI = 1.46-2.16), followed by cannabis-only use, and tobacco-only use. Compared to tobacco-only use, co-use (OR = 1.35, 95%CI = 1.08-1.69) and cannabis-only use (OR = 1.17, 95%CI = 1.00-1.37) were associated with higher adjusted odds for anxiety, but not for depression. Daily use (vs. non-daily use) of cigarettes, e-cigarettes, and cannabis were associated with higher adjusted odds for anxiety and depression.

CONCLUSIONS

Use of tobacco and/or cannabis, particularly co-use of both substances, were associated with poor mental health. Integrating mental health support with tobacco and cannabis cessation may address this co-morbidity.

A latent class analysis of patterns of tobacco and cannabis use in Australia and their health-related correlates

INTRODUCTION

The shifting landscape in Australia's tobacco and cannabis policies and emerging new products and modes of administration may increase experimentation and the risks of addiction to these drugs.

METHODS

We analysed cross-sectional data from the 2019 National Drug Strategy and Household Survey (n = 22,015) of Australians aged 14 and above. Latent class analysis was used to identify distinct groups based on types of tobacco and cannabis products used. The socio-demographic, health-rated correlates and past-year substance use of each latent class was examined.

RESULTS

A four-class solution was identified: co-use of tobacco and cannabis (2.4%), cannabis-only (5.5%), tobacco-only (8.0%) and non-user (84.0%). Males (odds ratio [OR] range 1.5-2.9), younger age (OR range 2.4-8.4), moderate to high psychological distress (OR range 1.3-3.0), using illicit substances in the last year (OR range 1.41-22.87) and high risk of alcohol use disorder (OR range 2.0-21.7) were more likely to be in the tobacco/cannabis use classes than non-users. Within the co-use class, 78.4% mixed tobacco with cannabis and 89.4% had used alcohol with cannabis at least once.

DISCUSSION AND CONCLUSIONS

Approximately 16% of respondents used tobacco or cannabis, or both substances, and no major distinct subgroups were identified by the use of different product types. Mental health issues and the poly-substance use were more common in the class who were co-users of cannabis and tobacco. Existing policies need to minimise cannabis and tobacco-related harms to reduce the societal burden associated with both substances.

Cannabis and nicotine co-use among primary care patients in a state with legal cannabis access

The aim of this exploratory analysis was to evaluate cannabis exposure, reasons for use and problematic cannabis use among adult primary care patients in Washington state (United States) who co-use cannabis and nicotine (tobacco cigarettes and/or nicotine vaping) compared to patients who endorse current cannabis use only. As part of a NIDA Clinical Trials Network (CTN) parent study, patients who completed a cannabis screen as part of routine primary care were randomly sampled (N = 5,000) to a receive a confidential cannabis survey. Patients were stratified and oversampled based on the frequency of past-year cannabis use and for Black, indigenous, or other persons of color. Patients who endorsed past 30-day cannabis use are included here (N = 1388). Outcomes included; prevalence of cannabis use, days of cannabis use per week and times used per day, methods of use, THC:CBD content, non-medical and/or medical use, health symptoms managed, and cannabis use disorder (CUD) symptom severity. We conducted unadjusted bivariate analyses comparing outcomes between patients with cannabis and current nicotine co-use to patients with cannabis-only use. Nicotine co-use (n = 352; 25.4 %) was associated with differences in method of cannabis use, THC:CBD content, days of use per week and times used per day, number of health symptoms managed, and CUD severity (all p < 0.001), compared to primary care patients with cannabis-only use (n = 1036). Interventions targeting cannabis and nicotine co-use in primary care are not well-established and further research is warranted given findings of more severe cannabis use patterns and the adverse health outcomes associated with co-use.

Associations Between Product Type and Intensity of Tobacco and Cannabis Co-use on the Same Day Among Young Adult Smokers: Smartphone-Based Daily-Diary Study

BACKGROUND

Co-use of tobacco and cannabis is highly prevalent among young US adults. Same-day co-use of tobacco and cannabis (ie, use of both substances on the same day) may increase the extent of use and negative health consequences among young adults. However, much remains unknown about same-day co-use of tobacco and cannabis, in part due to challenges in measuring this complex behavior. Nuanced understanding of tobacco and cannabis co-use in terms of specific products and intensity (ie, quantity of tobacco and cannabis use within a day) is critical to inform prevention and intervention efforts.

OBJECTIVE

We used a daily-diary data collection method via smartphone to capture occurrence of tobacco and cannabis co-use within a day. We examined (1) whether the same route of administration would facilitate co-use of 2 substances on the same day and (2) whether participants would use more tobacco on a day when they use more cannabis.

METHODS

This smartphone-based study collected 2891 daily assessments from 147 cigarette smokers (aged 18-26 years, n=76, 51.7% female) during 30 consecutive days. Daily assessments measured type (ie, cigarette, cigarillo, or e-cigarette) and intensity (ie, number of cigarettes or cigarillos smoked or number of times vaping e-cigarettes per day) of tobacco use and type (ie, combustible, vaporized, or edible) and intensity (ie, number of times used per day) of cannabis use. We estimated multilevel models to examine day-level associations between types of cannabis use and each type of tobacco use, as well as day-level associations between intensities of using cannabis and tobacco. All models controlled for demographic covariates, day-level alcohol use, and time effects (ie, study day and weekend vs weekday).

RESULTS

Same-day co-use was reported in 989 of the total 2891 daily assessments (34.2%). Co-use of cigarettes and combustible cannabis (885 of the 2891 daily assessments; 30.6%) was most commonly reported. Participants had higher odds of using cigarettes (adjusted odds ratio [AOR] 1.92, 95% CI 1.31-2.81) and cigarillos (AOR 244.29, 95% CI 35.51-1680.62) on days when they used combustible cannabis. Notably, participants had higher odds of using e-cigarettes on days when they used vaporized cannabis (AOR 23.21, 95% CI 8.66-62.24). Participants reported a greater intensity of using cigarettes (AOR 1.35, 95% CI 1.23-1.48), cigarillos (AOR 2.04, 95% CI 1.70-2.46), and e-cigarettes (AOR 1.48, 95% CI 1.16-1.88) on days when they used more cannabis.

CONCLUSIONS

Types and intensities of tobacco and cannabis use within a day among young adult smokers were positively correlated, including co-use of vaporized products. Prevention and intervention efforts should address co-use and pay attention to all forms of use and timeframes of co-use (eg, within a day or at the same time), including co-use of e-cigarettes and vaporized cannabis, to reduce negative health outcomes.

"What Do You Consider Use?" Perspectives of Black Youth on Cannabis Use

PURPOSE

Adolescent health surveillance systems are critical for understanding patterns of cannabis use; however, their limitations underscore the need for studies that generate new insights, particularly from individuals who are most impacted by negative outcomes. Our objectives were to learn about youths' cannabis use and their perceptions of their peers' cannabis use; their perspectives about trajectories of cannabis use over time and factors that influence trajectories; and perceived risks and benefits associated with cannabis use.

METHODS

A group model building approach was used to gather data about cannabis use from a sample of urban, Black youth. Information about participants' cannabis use was assessed on eligibility screener, enrollment survey, and through structured activities over the course of four group model building workshops.

RESULTS

Participants [(n = 20) mean age 18; 35% male and 95% Black] exclusively used the terms weed and blunts for cannabis. Youth who consume peers' blunts would not characterize themselves as cannabis users. Collectively, youth estimated the majority of Baltimore youth used cannabis by age 16 and that most used daily. Youth described cannabis as more beneficial than harmful. There were no gender differences in prevalence of use, but there were gender dynamics to shared use.

DISCUSSION

Participatory research with urban, Black youth suggests youths' perceptions are misaligned with the ways that researchers conceptualize cannabis use. To better understand the scope of youth cannabis use and its harms, it is critical to leverage input from youth with lived experience to ensure survey tools adequately capture the way youth see themselves using cannabis.

Determining the impact of cannabis use and severity on tobacco cessation outcomes: study protocol for a prospective tobacco treatment trial

BACKGROUND

Several evidence-based tobacco cessation treatment strategies exist, though significant barriers to cessation remain which must be addressed to improve abstinence rates for sub-populations of those smoking cigarettes. Cannabis co-use among those who use tobacco is common and appears to be increasing among adults in the United States (US). The literature evaluating the impact of cannabis use on tobacco cessation has been mixed and has several important limitations, which precludes development of treatment recommendations specific to individuals who use tobacco and co-use cannabis. To date, no prospective studies have evaluated the impact of cannabis use and severity on tobacco cessation or quantified cannabis use changes during tobacco treatment to assess for concurrent reductions, abstinence, or compensatory (i.e., increased) cannabis use. This study's aims are to: (1) evaluate tobacco cessation outcomes among participants who co-use cannabis compared to participants only using tobacco, (2) using daily diaries and biochemical verification, assess changes in cannabis use during tobacco treatment, and (3) assess for a dose-dependent impact of cannabis use on tobacco cessation.

METHOD

A multi-site, prospective, quasi-experimental 12-week tobacco treatment trial enrolling treatment-seeking adults (ages 18-40; N = 208) from three sites across South Carolina (US) who use tobacco daily and oversampling (2:1) those who co-use cannabis. Participants receive tobacco cessation pharmacotherapy (varenicline) paired with behavioral support, while cannabis use is not addressed as part of treatment. The primary outcome is 7-day point prevalence tobacco abstinence at the week 12 end of treatment visit, measured via biochemical verification and self-report. Secondary outcome measures include changes in cannabis use (via biochemical verification and self-report) during tobacco cessation treatment.

DISCUSSION

Results from this trial have the potential to inform tobacco treatment among those co-using cannabis, which may require a tailored approach to address the role of cannabis in quitting tobacco.

TRIAL REGISTRATION

The trial is registered with ClinicalTrials.gov: NCT04228965. January 14th, 2020.

Daily Cannabis Use Is a Barrier to Tobacco Cessation Among Tobacco Quitline Callers at 7-Month Follow-up

INTRODUCTION

Cannabis use is increasing among cigarette smokers in the United States. Prior studies suggest that cannabis use may be a barrier to smoking cessation. Yet, the extent to which this is the case among adults seeking to quit tobacco use remains unclear. Tobacco quitlines are the most common provider of no-cost treatment for adults who use smoke in the United States. This study investigated the association between cannabis use and smoking cessation outcomes among quitline callers.

AIMS AND METHODS

Participants included callers to the New York State Smokers' Quitline, who were seeking to quit smoking cigarettes and were contacted for outcome assessment 7 months after intake. Thirty-day point prevalence abstinence rates were calculated and compared among cannabis use groups, based on frequency of past-30-day cannabis use at baseline (none: 0 days, occasional: 1-9 days, regular: 10-19 days, and daily: 20-30 days).

RESULTS

Approximately 8.3% (n = 283) of participants (n = 3396) reported past-30-day cannabis use at baseline. Callers with daily cannabis use (20-30 days per month) had significantly lower odds of 30-day abstinence, relative to those who did not use cannabis (odds ratio = 0.5; 95% confidence interval [0.3, 0.9]).

CONCLUSIONS

Daily cannabis use appears to be associated with poorer smoking cessation treatment outcomes among adults seeking to quit smoking cigarettes via a quitline. Because quitlines are among the most accessible, affordable, and frequently utilized community-based treatments available in the United States, and the prevalence of cannabis use is increasing among cigarette smokers, detailed inquiry into cannabis use might enhance cigarette smoking cessation outcomes.

IMPLICATIONS

Quitlines are free of cost and accessible to millions of smokers in the United States. The current study found an inverse relationship between daily cannabis use at baseline and 30-day abstinence from cigarette smoking at 7-month follow-up among New York State Smokers' Quitline callers. Findings suggest that daily cannabis use may be a barrier to smoking cessation and sustained abstinence among those seeking help to stop smoking cigarettes.

Simultaneous quantification of urinary tobacco and marijuana metabolites using solid-supported liquid-liquid extraction coupled with liquid chromatography tandem mass spectrometry

Co-exposure to tobacco and marijuana has become common in areas where recreational marijuana use is legal. To assist in the determination of the combined health risks of this co-exposure, an analytical method capable of simultaneously measuring tobacco and marijuana metabolites is needed to reduce laboratory costs and the required sample volume. So far, no such analytical method exists. Thus, we developed and validated a method to simultaneously quantify urinary levels of trans-3'-hydroxycotinine (3OH-COT), cotinine (COT), and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (COOH-THC) to assess co-exposure to tobacco and marijuana. Urine (200 µL) was spiked with labelled internal standards and enzymatically hydrolyzed to liberate the conjugated analytes before extraction using solid-supported liquid-liquid extraction (SLE) with ethyl acetate serving as an eluent. The target analytes were separated on a C18 (4.6 × 100 mm, 5 μm) analytical column with a gradient mobile phase elution and analyzed using tandem mass spectrometry with multiple reaction monitoring of target ion transitions. Positive electrospray ionization (ESI) was used for 3OH-COT and COT, while negative ESI was used for COOH-THC. The total run time was 13 min. The extraction recoveries were 18.4-23.9 % (3OH-COT), 65.1-96.8 % (COT), and 80.6-95.4 % (COOH-THC). The method limits of quantification were 5.0 ng/mL (3OH-COT) and 2.5 ng/mL (COT and COOH-THC). The method showed good accuracy (82.5-98.5 %) and precision (1.22-6.21 % within-day precision and 1.42-6.26 % between-day precision). The target analytes were stable for at least 144 h inside the autosampler (10 °C). The analyses of reference materials and 146 urine samples demonstrated good method performance. The use of a 96-well plate for preparation makes the method useful for the analysis of large numbers of samples.

Prevalence of cannabis use among tobacco smokers: a systematic review protocol

INTRODUCTION

Understanding the prevalence of cannabis use among tobacco smokers has important implications for research in terms of intervention effectiveness and measurement in smoking cessation trials. The co-use of these substances also has important implications for health service planning, specifically ensuring appropriate and adequate clinical treatment. To date, there have been no synthesis of the literature on the prevalence of tobacco and cannabis co-use in adult clinical populations. Improved understanding of the current prevalence, route of administration and specific subpopulations with the highest rates of tobacco and cannabis co-use will support future intervention development. We aim to provide a pooled estimate of the percentage of smokers who report using cannabis and to examine the prevalence of co-use by sociodemographic characteristics.

METHODS AND ANALYSIS

We will conduct a systematic review using six scientific databases with published articles from 2000 to 2022 inclusive (CENTRAL, CINAHL, EMBASE, Medline, PsycINFO, Psychology and Behavioural Sciences Collection, Scopus). Peer-reviewed journal articles published in English that report on tobacco and cannabis use will be included. Rates of co-use (simultaneous or sequentially) and routes of administration will be assessed. Use in populations groups will be described. Quality assessments will be conducted for all included studies. Data will be synthesised using a narrative approach. This study will be conducted from June 2022 to the end of August 2022.

ETHICS AND DISSEMINATION

This review is based on previously published data and, therefore, ethical approval or written informed consent will not be required. It is the intention of the research team to disseminate the results of the systematic review as a peer-reviewed publication and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42020194051.

Smartphone Apps for Vaping Cessation: Quality Assessment and Content Analysis

Background

As the prevalence of electronic cigarette (e-cigarette) use, or vaping, continues to grow, particularly among young people, so does the need for research and interventions to address vaping.

Objective

This study examines the quality of free vaping cessation apps, their contents and features, popularity among users, and adherence to evidence-based principles.

Methods

A systematic search of existing apps for vaping cessation was conducted in December 2020. Eligible apps were free, in English, and included features specifically targeting vaping cessation. Each app included in the analysis was used daily for at least seven consecutive days, assessed using the Mobile App Rating Scale, and rated by at least two authors (AK, EL, or SS) based on adherence to evidence-based practices. Intraclass correlation coefficient (ICC) estimates were computed to assess interrater reliability (excellent agreement; ICC 0.92; 95% CI 0.78-0.98).

Results

A total of 8 apps were included in the quality assessment and content analysis: 3 were developed specifically for vaping cessation and 5 focused on smoking cessation while also claiming to address vaping cessation. The mean of app quality total scores was 3.66 out of 5. Existing vaping cessation apps employ similar approaches to smoking cessation apps. However, they are very low in number and have limited features developed specifically for vaping cessation.

Conclusions

Given the lack of vaping cessation interventions at a time when they are urgently needed, smartphone apps are potentially valuable tools. Therefore, it is recommended that these apps apply evidence-based practices and undergo rigorous evaluations that can assess their quality, contents and features, and popularity among users. Through this process, we can improve our understanding of how apps can be effective in helping users quit vaping.

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.

Use of Inhaled Nicotine and Cannabis Products among Adults Who Vape Both Substances

BACKGROUND

Co-occurring use (co-use) of nicotine and cannabis is common, and represents a broad range of use behaviors, including concurrent use, sequential use, and co-administration. Co-use has primarily been examined through the lens of smoked tobacco and cannabis. Little is known about those who co-use vaped nicotine and cannabis, and the degree to which specific co-use behaviors are associated, based on mode of use and/or substance.

METHODS

We conducted an online pilot survey on use behaviors related to inhaled modes of nicotine and cannabis. The survey was administered to 112 concurrent vapers of these substances. Descriptive analyses examined sample characteristics and co-administered vaping and smoking behaviors. Logistic regressions examined associations in use behaviors by mode and substance.

RESULTS

Participants who vaped nicotine and cannabis monthly also reported monthly smoking of cannabis (100%), and cigarettes (58%). Most exhibited moderate-to-high degrees of mental health and substance use problems requiring clinical intervention. Monthly concurrent use exhibited more differences by mode, and more similarities by substance. Specific sequential use practices showed mode-specific associations; with greater frequency of cigarette smoking and nicotine vaping. Co-administration was associated with more frequent tobacco and cannabis smoking.

CONCLUSIONS

Those who regularly vape nicotine and cannabis tend to engage in some form of smoking. Different subsets of nicotine and cannabis co-use behaviors showed different associations with patterns of use and modes of drug delivery. Findings underscore the diversity of nicotine and cannabis use behaviors among co-users, and the importance of considering associations by both substance and mode of use.

The Relationship between Cannabis and Tobacco Co-administration and Long-Term Patterns of Cannabis Use in Young Adults Who Use Stimulants: A Prospective Population-Based Study

BACKGROUND

Co-administering cannabis with tobacco (i.e. co-administration of the substances mixed together) is a common practice among cannabis users, but the consequences of this practice are not well understood. This study examines the relationship between co-administering cannabis with tobacco and the long-term frequency of cannabis use in a young adult population group with high rates of cannabis and tobacco use.

METHODS

The data are from an Australian prospective population-based study of young adults who recurrently used amphetamine-type stimulants (ATS). The mean age of participants was 20.8 years at baseline, sample size (n = 277), and 47% were female. We examined the frequency and quantity of cannabis consumption over 4 ½ years. Negative binomial regression analysis was conducted to examine the frequency of cannabis use at 12-month follow-up and at 4 ½ years, with co-administering practices as the predictor.

RESULTS

At every time interval, participants who always co-administered their cannabis with tobacco used cannabis on more days in the last month than those who only sometimes co-administered, rarely co-administered, or never co-administered these substances (p < 0.001). Sometimes co-administering cannabis with tobacco at baseline predicted more frequent cannabis use at 12-month follow-up (adjusted IRR: 2.25, 95% CI: 1.05, 4.78), independently of the baseline frequency of cannabis use. However, levels of co-administering cannabis with tobacco at 12-month follow-up (rarely, sometimes, and always) did not predict high levels of cannabis use at 4 ½ years follow-up after adjusting for cannabis use at 12-month follow-up.

CONCLUSIONS

Among people who use ATS and cannabis, frequent cannabis use may be a marker of the practice of co-administering cannabis with tobacco, and can be used to target tobacco cessation interventions in these populations.

An Examination of Risk Factors for Tobacco and Cannabis Smoke Exposure in Adolescents Using an Epigenetic Biomarker

Objective: Evolving patterns of nicotine and cannabis use by adolescents require new tools to understand the changing epidemiology of these substances. Here we describe the use of a novel epigenetic biomarker sensitive to both tobacco and cannabis smoke in a longitudinal sample of high-risk adolescents. We examine risk factors for positivity for this epigenetic biomarker in comparison to positivity for conventional serum biomarkers of nicotine and cannabis use. Method: Eastern Iowa 10th graders who had a friend or family member who smoked were eligible to participate in a longitudinal study over 10-12th grades. Subjects provided self-report data on nicotine, tobacco, and cannabis use patterns as well as blood samples that were used for serum cotinine and THC assays. DNA was prepared for analysis of methylation at the CpG cg05575921, a sensitive indicator of smoke exposure. Relationships between positivity for each these biomarkers and a variety of risk factors, including demographics, family and peer relationships, psychopathology, willingness to smoke, and perceptions of typical cigarette and cannabis users, were examined at the 10th (n = 442), 11th (n = 376), and 12th (n = 366) grade timepoints. Results: A increasing proportion of subjects were positive for cotinine (5-16%), THC (3-10%), and cg05575921 methylation (5-7%) across timepoints, with some overlap. Self-reported combusted tobacco and cannabis use was strongly correlated with all biomarkers, whereas cg05575921 methylation was not correlated with reported e-cigarette use. Dual users, defined as those positive for nicotine and THC in the 12th grade showed the greatest cumulative smoke exposure, indicated by cg05575921 methylation. Subjects reported more positive attitudes toward cannabis users than cigarette smokers, and willingness to smoke and positive perceptions of tobacco and cannabis smokers were significant risk factors for biomarker positivity across timepoints. Conclusion: We conclude that measurement of cg05575921 methylation in adolescents is a useful tool in detecting tobacco smoking in adolescents, and may be a novel tool for the detection of cannabis smoking and cannabis and tobacco co-use, though non-combusted forms of nicotine use do not appear to be detectable by this method.

Cannabis use and co-use in tobacco smokers and non-smokers: prevalence and associations with mental health in a cross-sectional, nationally representative sample of adults in Great Britain, 2020

BACKGROUND AND AIMS

In Great Britain, cannabis and tobacco are commonly used substances, both independently and together. Use of either substance is associated with mental health problems, but prevalence of co-use within these populations is unknown. We aimed to (1) estimate prevalence of cannabis use, frequency of use and routes of administration (ROA) among tobacco smokers and non-smokers and (2) investigate mental health problems among non-users, tobacco-only, cannabis-only and co-users of both substances.

DESIGN

Cross-sectional national on-line survey (Action on Smoking and Health) fielded in February-March 2020.

SETTING

Great Britain.

PARTICIPANTS

Adults in Great Britain aged ≥ 18 years (n = 12 809) MEASUREMENTS: Tobacco use status [smoker (daily or non-daily) or non-smoker (never or ex-smoker)], cannabis use frequency (never to daily), detailed ROAs of cannabis, self-reported treatment for mental health disorders (depression, anxiety and any). Statistically weighted prevalence estimates were computed to ensure representativeness. Correlates were assessed using χ² tests and logistic regression.

FINDINGS

In Great Britain in 2020, 7.1% of the sample had used cannabis in the past year. Tobacco smokers had greater odds of using cannabis in the past year (21.9%) and using cannabis daily (8.7%) than non-smokers [past-year: 4.7%; adjusted odds ratio (aOR) = 10.07, 95% confidence interval (CI) = 8.4-12.0; daily: 0.7%; aOR = 24.6, 95% CI = 18.0-33.6)]. Co-administration with tobacco was common (46.2% of non-smokers, 80.8% of tobacco smokers). Co-users reported the highest prevalence of any treatment for mental health problems (54.2%) in comparison to cannabis-only (45.8%), tobacco-only (33.2%) and non-users (22.7%; all P ≤ 0.05).

CONCLUSION

Approximately one in 13 adults in Great Britain reports having used cannabis in the past year, approximately four times as many among cigarette smokers as non-smokers. Co-administration of cannabis and tobacco, via smoking, appears to be common, including among self-identified non-smokers. Mental health problems appear to be particularly common among dual users.

A mixed-methods study to inform the clarity and accuracy of cannabis-use and cannabis-tobacco co-use survey measures

BACKGROUND

Legalization of medical and recreational cannabis in US states has been accompanied by increases in availability, acceptability, and diversity in methods of cannabis use, as well as an increase in devices and methods for cannabis-tobacco co-use. Updated and specific survey measures of cannabis and cannabis-tobacco co-use are needed.

METHODS

We employed a mixed-methods approach to identify sources of specification and measurement error in cannabis and cannabis-tobacco co-use measures. We surveyed and interviewed 36 young adult (age 18-29) cannabis and tobacco co-users in California (2017-2018), triangulated with document analysis of online cannabis websites and forums. We investigated how survey reports of cannabis use and cannabis-tobacco co-use compared to narrative descriptions provided during in-depth interviews. We identify key strategies for researchers collecting self-reported survey data to enhance accuracy and comprehensiveness of measures.

FINDINGS

Potential sources of survey error included: broad variation in cannabinoid content and concentration, inconsistent interpretation of questions between participants and researchers (e.g. blunts were not considered co-use), and substantial variation in dosage within and between products. No evidence of survey recall bias or response editing was detected.

CONCLUSION

To enhance survey accuracy, we recommend surveys specify which cannabis delivery methods and forms are included and excluded in each measure, differentiate between cannabis products, and explicitly include or exclude CBD product use.

Accurate and sufficient measurement of cannabis and tobacco co-use: agreement, consensus and the path forward

Expert consensus surrounding cannabis-tobacco co-use measurement is critical and necessary in providing a harmonized data bank to those interested in measuring co-use but require expert recommendations. The need for consensus signifies the next step forward in the accurate and sufficient measurement of cannabis-tobacco co-use to improve public health efforts.

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.