A systematic review and Bayesian meta-analysis of interventions which target or assess co-use of tobacco and cannabis in single- or multi-substance interventions

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.

Predicting cannabis use moderation among a sample of digital self-help subscribers: A machine learning study

BACKGROUND

For individuals who wish to reduce their cannabis use without formal help, there are a variety of self-help tools available. Although some are proven to be effective in reducing cannabis use, effect sizes are typically small. More insight into predictors of successful reduction of use among individuals who frequently use cannabis and desire to reduce/quit could help identify factors that contribute to successful cannabis use moderation.

METHODS

We analyzed data taken from a randomized controlled trial comparing the effectiveness of the digital cannabis intervention ICan to four online modules of educational information on cannabis. For the current study, we included 253 participants. Success was defined as reducing the grams of cannabis used in the past 7 days at baseline by at least 50 % at 6-month follow-up. To train and evaluate the machine learning models we used a nested k-fold cross-validation procedure.

RESULTS

The results show that the two models applied had comparable low AUROC values of .61 (Random Forest) and .57 (Logistic Regression). Not identifying oneself as a cannabis user, not using tobacco products, high levels of depressive symptoms, high levels of psychological distress and high initial cannabis use values were the relatively most important predictors for success, although overall the associations were not strong.

CONCLUSIONS

Our study found only modest prediction accuracy when using machine learning models to predict success among individuals who use cannabis and desire to reduce/quit and show interest in digital self-help tools.

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.

Anxiety sensitivity reduction-smoking cessation intervention among individuals who engage in dual cigarette and cannabis use: A secondary analysis

INTRODUCTION

Cannabis use among individuals who smoke is prevalent in the general population and related to adverse health effects, including higher levels of interoceptive perturbation (i.e., a disturbance in internal experiences). An important aspect of smoking cessation among individuals who co-use cannabis is to address behavioral associations between physiological sensations and habitual behaviors via integrated treatments focused on reducing reactivity to internal perturbations such as anxiety sensitivity (i.e., the belief that such symptoms produce personal harm).

METHODS

The current study involved a secondary analysis of a randomized clinical trial (RCT) of an integrated anxiety sensitivity-smoking cessation intervention compared to standard smoking cessation. The current study sought to extend findings from the initial trial to examine if the integrated intervention produced better smoking cessation outcomes than standard care among individuals who engage in dual cigarette and cannabis use. Participants were 149 adults who engage in dual cigarette and cannabis use (41.6 % female; Mage = 30.89, SD = 13.1).

RESULTS

Results indicated that the anxiety sensitivity intervention produced statistically significant differences in distal (long-term) smoking abstinence at 3-, 6-, and 12-month follow-up assessments but not proximal (short-term; quit-week to 2-weeks) smoking abstinence.

CONCLUSIONS

Overall, the potential of an integrated anxiety sensitivity smoking cessation intervention to yield better long-term smoking abstinence rates than standard cessation treatment among individuals who engage in dual cigarette and cannabis use is clinically significant.

Nicotine replacement therapy 'gift cards' for hospital inpatients who smoke: a prospective before-and-after controlled pilot evaluation

INTRODUCTION

A common barrier identified by individuals trying to quit smoking is the cost of cessation pharmacotherapies. The purpose of this evaluation was to: (1) Assess the feasibility of offering nicotine replacement therapy (NRT) 'gift cards' to hospitalised smokers for use posthospitalisation; and, (2) Estimate the effect of providing NRT gift cards on 6-month smoking abstinence.

METHODS

A prospective, quasi-experimental, before-and-after controlled cohort design with random sampling was used to compare patients who had received the Ottawa Model for Smoking Cessation (OMSC) intervention ('control') with patients who received the OMSC plus a $C300 Quit Card ('QCI'), which they could use to purchase any brand or form of NRT from any Canadian pharmacy.

RESULTS

750 Quit Cards were distributed to the three participating hospitals of which 707 (94.3%) were distributed to patients. Of the cards received by patients, 532 (75.2%) were used to purchase NRT. A total of 272 participants completed evaluation surveys (148 control; 124 QCI).Point prevalence abstinence rates adjusted for misreporting among survey responders were 15.3% higher in the QCI group, compared with controls (44.4% vs 29.1%; OR 1.95, 1.18-3.21; p=0.009). Satisfaction was high among participants in both groups, and among staff delivering the QCI. QCI participants rated the intervention as high in terms of motivation, ease of use and helpfulness.

CONCLUSIONS

The NRT gift card appears to be a feasible and effective smoking cessation tool that removes a primary barrier to the use of evidence-based smoking cessation pharmacotherapies, while motivating both patients and health providers.

Does tobacco dependence worsen cannabis withdrawal in people with and without schizophrenia-spectrum disorders?

BACKGROUND AND OBJECTIVES

Rates of cannabis use disorder (CUD) are higher in people with schizophrenia than in the general population. Irrespective of psychiatric diagnosis, tobacco co-use is prevalent in those with CUD and leads to poor cannabis cessation outcomes. The cannabis withdrawal syndrome is well-established and increases cannabis relapse risk. We investigated whether cannabis withdrawal severity differed as a function of high versus no/low tobacco dependence and psychiatric diagnosis in individuals with CUD.

METHOD

Men with CUD (N = 55) were parsed into four groups according to schizophrenia diagnosis and tobacco dependence severity using the Fagerstrom Test for Nicotine Dependence (FTND): men with schizophrenia with high tobacco dependence (SCT+, n = 13; FTND ≥ 5) and no/low tobacco dependence (SCT-, n = 22; FTND ≤ 4), and nonpsychiatric controls with high (CCT+, n = 7; FTND ≥ 5) and no/low (CCT-, n = 13; FTND ≤ 4) tobacco dependence. Participants completed the Marijuana Withdrawal Checklist following 12-h of cannabis abstinence.

RESULTS

There was a significant main effect of tobacco dependence on cannabis withdrawal severity (p < .001). Individuals with high tobacco dependence had significantly greater cannabis withdrawal severity (M = 13.85 [6.8]) compared to individuals with no/low tobacco dependence (M = 6.49, [4.9]). Psychiatric diagnosis and the interaction effects were not significant. Lastly, cannabis withdrawal severity positively correlated with FTND (r = .41, p = .002).

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Among individuals with CUD and high tobacco dependence, cannabis withdrawal severity was elevated twofold, irrespective of diagnosis, relative to individuals with CUD and no/low tobacco dependence. Findings from this study emphasize the importance of addressing tobacco co-use when treating CUD.

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.

Educational Attainment and Differences in Patterns of Alcohol, Cannabis, and Tobacco Use Among Young Adults

Multigroup latent profile analysis examined whether patterns of alcohol, cannabis, and tobacco use varied between college student and nonstudent young adults ( N = 745), and profiles were characterized by alcohol- and drug-related problems, psychological distress, and perceived stress. Findings supported three profiles (high use across substances, primarily high tobacco use, and low use across substances) among students. Students in the high use group, relative to other groups, experienced the highest number of problems and psychological distress. Among nonstudents, two profiles emerged (high use across substances and primarily high tobacco use), and noncollege participants in the high use group experienced the highest problems, psychological distress, and perceived stress. Students, compared to nonstudents, reported more variability in their substance use profiles, as a low substance use group was not observed among nonstudents. Prevention and intervention efforts should target nonstudents, which could aid in reducing negative health outcomes based on disparities in education.

Prevalence, perceptions, and patterns of cannabis use among cardiac inpatients at a tertiary care hospital: A cross-sectional survey

Background

Cannabis use may adversely affect cardiovascular health. Patterns of use by cardiac patients are unknown. We evaluated the prevalence, perceptions, and patterns of cannabis use among cardiac inpatients.

Methods

A consecutive cross-section of cardiac inpatients, hospitalized between November 2019 and May 2020, were surveyed in-person or via telephone. Descriptive statistics and logistic regression were used to examine the characteristics of cannabis use.

Results

The prevalence of past-12-month cannabis use was 13.8% (95% confidence interval [CI]: 11.8%-16.0%). Characteristics independently associated with cannabis use were as follows: age < 64 years (< 44 years, odds ratio [OR] = 3.96 [95% CI: 1.65-9.53]; age 45-64 years, OR = 2.72 [95% CI: 1.65-4.47]); tobacco use in the previous 6 months (OR = 1.91 [95% CI: 1.18-3.07]); having a cannabis smoker in one's primary social group (OR = 4.17 [95% CI: 2.73-6.38]); and a history of a mental health diagnosis (OR = 1.82 [95% CI: 1.19-2.79]). Among those using cannabis, 70.5% reported smoking or vaping it; 47.2% reported daily use. Most did not know the tetrahydrocannabinol (THC; 71.6%) or cannabidiol (CBD; 83.3%) content of their cannabis, or the dose of cannabis in their edibles (66.7%). As defined by Canada's Lower Risk Cannabis Use Guidelines, 96.7% of cannabis users reported ≥ 1 higher-risk use behaviour (mean = 2.3, standard deviation = 1.2). Over 60% of patients expressed no intention to quit or reduce cannabis use in the next 6 months.

Conclusions

Cannabis use appears prevalent among cardiac patients. Most users demonstrated higher-risk use behaviours and low intentions to quit. Further work is needed to understand the impacts of cannabis use on the cardiovascular system and to develop guidelines and educational tools relating to lower-risk use, for cardiac patients and providers.

Cannabis Use in Young and Adult University Students Before and During the COVID-19 Lockdown, According to Gender and Age

The objectives were: (a) to establish cannabis use prevalence in university students; (b) to determine the changes in consumption of cannabis between prior to and during lockdown. Problematic consumption, gender, and age were taken into account to establish risk groups. Of 1,472 participants between 18-54 years (M = 27.51), 8.01% reported using cannabis before and/or during lockdown (56.6% male). The Cannabis Abuse Screening Test (CAST) was used to detect cannabis abuse. The main form of consumption was spliffs (89.9%). The mean of spliffs consumed per day decreased during lockdown, but was only significant in male and in the 18-24 group. This decrease was also significant for all three levels of CAST problematic use. Users with moderate addiction and dependence reduced their average number of spliffs consumed per day during lockdown to a greater extent than those without addiction. These findings establish target groups of prevention interventions in the university.

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.

Age-period-cohort analysis of trends in tobacco smoking, cannabis use, and their co-use in the Australian population

BACKGROUND AND AIM

The prevalence of tobacco smoking has declined in most high-income countries, while cannabis use has been rising. Moreover, cannabis use has been found to have increased among cigarette smokers in recent years in jurisdictions where it has been either decriminalized or legalized. This study measured trends in cannabis, tobacco and the co-use of cannabis and tobacco in Australia.

DESIGN

Age-period-cohort analysis.

SETTING AND PARTICIPANTS

Participants were n = 143 344 individuals aged 18-80 years who participated in Australia's National Drug Strategy Household Surveys (NDSHS) between 2001 and 2019.

MEASUREMENTS

Regular (weekly/more frequently): (1) tobacco smoking only, (2) cannabis use only and (3) the co-use of cannabis and tobacco.

FINDINGS

Prevalence of only smoking tobacco decreased in all age groups (P < 0.001) and birth cohorts between 2001 and 2019, but the co-use of cannabis and tobacco did not. Younger cohorts were much less likely to co-use tobacco and cannabis (P = 0.02). Period trends showed that both cannabis use only and the co-use of cannabis and tobacco have increased since 2013.

CONCLUSION

There has been a consistent decrease in exclusive tobacco smoking across age, period and birth cohorts between 2001 and 2019 in Australia, although there is a recent increasing period trend in cannabis use with or without tobacco. The non-decreasing trend of co-use may reflect the strong tobacco control policies introduced over the period and changing attitudes towards cannabis use in Australia.

Clinical management of cannabis withdrawal

BACKGROUND AND AIMS

Cannabis withdrawal is a well-characterized phenomenon that occurs in approximately half of regular and dependent cannabis users after abrupt cessation or significant reductions in cannabis products that contain Δ⁹ -tetrahydrocannabinol (THC). This review describes the diagnosis, prevalence, course and management of cannabis withdrawal and highlights opportunities for future clinical research.

METHODS

Narrative review of literature.

RESULTS

Symptom onset typically occurs 24-48 hours after cessation and most symptoms generally peak at days 2-6, with some symptoms lasting up to 3 weeks or more in heavy cannabis users. The most common features of cannabis withdrawal are anxiety, irritability, anger or aggression, disturbed sleep/dreaming, depressed mood and loss of appetite. Less common physical symptoms include chills, headaches, physical tension, sweating and stomach pain. Despite limited empirical evidence, supportive counselling and psychoeducation are the first-line approaches in the management of cannabis withdrawal. There are no medications currently approved specifically for medically assisted withdrawal (MAW). Medications have been used to manage short-term symptoms (e.g. anxiety, sleep, nausea). A number of promising pharmacological agents have been examined in controlled trials, but these have been underpowered and positive findings not reliably replicated. Some (e.g. cannabis agonists) are used 'off-label' in clinical practice. Inpatient admission for MAW may be clinically indicated for patients who have significant comorbid mental health disorders and polysubstance use to avoid severe complications.

CONCLUSIONS

The clinical significance of cannabis withdrawal is that its symptoms may precipitate relapse to cannabis use. Complicated withdrawal may occur in people with concurrent mental health and polysubstance use.

Characterizing tobacco and marijuana use among youth combustible tobacco users experiencing homelessness - considering product type, brand, flavor, frequency, and higher-risk use patterns and predictors

BACKGROUND

Cigarette smoking is three times more prevalent among youth experiencing homelessness compared with the general population. Co-use of tobacco and marijuana is also common. The aim of this study is to characterize tobacco and marijuana use among youth experiencing homelessness who use combustible tobacco in a Midwestern city to inform smoking cessation intervention.

METHODS

This study included 96 youth (ages 14-24 years; 52% male, 39% female, 5% transgender/non-binary) attending a homeless drop-in center who had used at least one combustible tobacco product in the past week. We assessed past-month use of tobacco products and marijuana, other product use characteristics (e.g., frequency, brand and flavor), and psychosocial predictors of more frequent (i.e., daily) use of combustible tobacco and marijuana.

RESULTS

Most youth experiencing homelessness with past-week combustible tobacco use had used cigarettes (n = 85, 88.5%), cigars (n = 89, 92.7%), and marijuana (n = 82, 85.4%) in the past month. One-third (n = 34) used electronic vapor products (EVPs), 19.8% (n = 19) smoked hookah, and 11.5% (n = 11) used smokeless tobacco (ST). Most marijuana users co-administered with tobacco (n = 67, 69.8%). Daily combustible tobacco smoking was associated with having a child and smoking out of boredom/habit. Daily marijuana use was associated with using substances to cope with one's housing situation. Newport (n = 66, 72.5%) and Black & Mild (n = 48, 51.1%) were the most popular brands of cigarettes and cigars among ever users. Most non-combustible tobacco ever users reported not having a usual brand (EVPs: n = 51, 73.9%; ST: n = 16, 57.1%). Cigar smokers reported the most varied selection of flavors.

CONCLUSIONS

Young combustible tobacco users experiencing homelessness engage in high-risk use patterns, including poly-tobacco use, co-use of tobacco with marijuana, and frequent combustible product use. Interventions that consider the full context of tobacco and marijuana use are needed to support smoking cessation in this population.

Towards quantifying the reciprocal associations between frequency of cannabis use and alcohol consumption: a cross-lagged analysis from the CONSTANCES cohort

OBJECTIVE

Disentangle the temporal relationships between frequency of cannabis use and alcohol consumption.

METHODS

A cross-lagged model providing standardised coefficients (SCs)±their standard errors in 13 255 men and 13 696 women enrolled in 2015 or 2016 in the French population-based 'CONSulTANts des Centres d'Examens de Santé' (CONSTANCES) cohort. Cannabis use was categorised as follows: 'No use during the past 12 months', 'Use during the past 12 months but not in the past month' and 'Use in the past month' for cannabis use at baseline, and No use during the past 12 months, 'Use less than once per month' and 'Use once per month or more' for cannabis use at 1 year of follow-up. Alcohol consumption was measured at baseline and at 1 year of follow-up and three categories were determined: low risk (<28 drinks per week in men; <14 drinks per week in women), moderate risk (≥28 and<42 in men; ≥14 and<28 in women) and high risk (≥42 in men; ≥28 in women). Analyses were adjusted for age, sex, education, income, tobacco consumption, self-rated health status and depressive symptoms.

RESULTS

Both associations from alcohol to cannabis and from cannabis to alcohol were significant (SC=0.02±0.01 with p=0.003 and SC=0.06±0.01 with p<0.001, respectively). However, the SC of the association from cannabis to alcohol was three times higher than the opposite association (p<0.001). After stratification for sex, SCs of the association from cannabis to alcohol were more than two times higher than for the opposite association in men, and more than four times higher in women (both p<0.001).

CONCLUSIONS

The association between frequency of cannabis use and subsequent alcohol consumption was stronger than the opposite association. This finding encourages considering the risk of increased alcohol consumption among cannabis users.

Barriers and facilitators to using vaporised nicotine products as smoking cessation aids among people receiving treatment for substance use disorder

INTRODUCTION

Vaporised nicotine products (VNPs) may be useful smoking cessation aids for people in alcohol and other drug (AOD) treatment, a population with high tobacco-related morbidity and mortality rates. This qualitative study aimed to examine the barriers and facilitators of using VNPs as part of a clinical trial to reduce or quit smoking among people in AOD treatment.

METHODS

Thirteen people in AOD treatment who were participating in a trial of VNPs for smoking cessation (QuitENDs) completed a brief semi-structured interview examining experiences of using VNPs to reduce or quit smoking. Transcribed data was analysed using the iterative categorisation framework.

RESULTS

Many participants expressed the benefit of having a smoking cessation aid that addressed nicotine cravings and the behavioural hand-to-mouth action to help them reduce or quit smoking. Although many participants reported that VNPs were easy to use, some found maintaining the device to be challenging. Some participants described Australian regulations limiting use of VNPs as reducing their desire to use the device as a cessation aid. Many participants attempting to reduce or quit tobacco and cannabis simultaneously stated that VNPs alone were insufficient to help them reduce or quit tobacco.

CONCLUSIONS

VNPs hold significant promise as smoking cessation aids among people in AOD treatment because of their unique ability to satisfy both nicotine cravings and behavioural habits. However, multiple barriers, such as accessibility, maintenance, and the challenges of reducing other substance use simultaneously also need to be addressed for optimal engagement in clinical trials with VNPs to quit smoking.

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.

Correlates of lifetime blunt/spliff use among cigarette smokers in substance use disorders treatment

BACKGROUND

Co-use of tobacco and cannabis has been associated with greater dependence on and lower quit rates for both substances. Tobacco/cannabis co-use among individuals with substance use disorders (SUDs), a population with high rates of cigarette smoking, may hinder the effectiveness of smoking cessation interventions. We examined rates of lifetime (i.e., ever vs. never) cannabis use among current cigarette smokers in SUD treatment, and we identified the subgroup who had used tobacco and cannabis together in the form of blunts and/or spliffs. We then examined variables associated with lifetime use of blunts and/or spliffs.

METHODS

We surveyed 562 clients in 20 residential SUD treatment programs in California, USA, in 2019. Measures included demographics, lifetime use of any cannabis product, lifetime use of blunt/spliffs, patterns of tobacco use, and smoking cessation-related questions. We asked current cigarette smokers who also reported lifetime cannabis use whether they had ever used blunts and/or spliffs. We then assessed relationships of demographic, tobacco use, use of cannabis/tetrahydrocannabinol (THC) in e-cigarettes/vape pens, and smoking cessation-related variables with ever use versus never use of blunts/spliffs.

RESULTS

Among 340 current cigarette smokers, 93.2% (n = 317) reported lifetime use of any cannabis product. Among current cigarette smokers with lifetime cannabis use, 64.4% reported lifetime blunt/spliff use. Compared to those who had never used blunts/spliffs, lifetime blunt/spliff users were more likely to be younger (OR = 0.93, 95% CI 0.90-0.95), more likely to report lifetime use of cigars/cigarillos (OR = 2.95, CI 1.37-6.32), and to have ever used cannabis/THC in e-cigarettes/vape pens (OR = 4.26, CI 1.54-11.80). They were less often ready to quit smoking within 30 days (OR = 0.37, CI 0.23-0.60), but more likely to want help with smoking cessation (OR = 2.39, CI 1.52-3.77).

CONCLUSION

Current cigarette smokers in SUD treatment reported a high prevalence of lifetime cannabis use. Smokers with a history of blunt/spliff use were more likely to report lifetime use of e-cigarettes/vape pens for cannabis/THC delivery. They wanted help to quit smoking, but felt less prepared to quit in the next 30 days. Cannabis co-use may warrant clinicians' attention when providing smoking cessation interventions during SUD treatment.

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.