Co-Use, Simultaneous Use, and Mixing of Cannabis and Tobacco: A Cross-National Comparison of Canada and the US by Cannabis Administration Type

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.

The relationship between cannabis and nicotine use: A systematic review and meta-analysis

BACKGROUND AND AIMS

Cannabis and nicotine (tobacco or e-cigarettes) use commonly co-occurs and understanding their relationship can help to inform public health strategies to prevent their harms. We conducted a systematic review and meta-analysis to estimate the association of cannabis use given prior nicotine use and vice versa.

METHODS

PubMed, Embase, PsycINFO, Google Scholar and a hand-search were conducted in 2023 for longitudinal studies of the general population with no restrictions in settings (locations). Random-effects meta-analysis was conducted to estimate odds ratios between cannabis and nicotine use in both directions. The impact of unmeasured confounding was assessed using E-values.

RESULTS

From 5387 identified records, we included 20 studies. Among cannabis-naïve youths, baseline use of any nicotine products was positively associated with initiation of any cannabis use at follow-up [odds ratio (OR) = 5.39, 95% confidence interval (CI) = 3.19, 9.11; adjusted OR (aOR) = 2.59, 95% CI = 2.01, 3.32]. In nicotine-naïve participants (youths + adults), baseline cannabis use was positively associated with the initiation of any nicotine use at follow-up (OR = 4.08, 95% CI = 2.05, 8.11; aOR = 2.94, 95% CI =1.54, 5.61). There were no significant associations between baseline cannabis use and subsequent initiation of any nicotine (aOR = 3.29, 95% CI = 0.85, 12.76) or daily nicotine use (aOR = 2.63, 95% CI = 0.41, 16.95) among youths. The median E-values were 5.5 for nicotine exposure and cannabis use initiation and 4.1 for cannabis exposure and nicotine use initiation, indicating that substantial unmeasured confounding would need to have a strong association with both outcomes to fully explain away the cannabis and nicotine relationship.

CONCLUSION

Although the evidence for associations between cannabis use and tobacco use is mixed, a majority of studies to date have found that cannabis use is associated with prior nicotine use and vice versa.

Testing a Brief Quitline Intervention for Tobacco Cannabis Co-Users: A Randomized Controlled Pilot Study

Background: Tobacco cannabis co-use is common and becoming more prevalent. Frequent and heavy users of cannabis may struggle to quit smoking. Quitlines offer free cessation treatment in the United States and 25% of quitline callers may also be cannabis users. The present paper describes a randomized pilot study of a tailored intervention for cannabis and cigarette co-users. The intervention combines the quitline smoking cessation treatment with a motivational enhancement therapy-based cannabis intervention. Methods: The randomized pilot study was conducted within four state-funded quitlines with quitline coaches as interventionists. 102 quitline callers who were cannabis and cigarette co-users were randomized to receive treatment as usual (TAU) or the new Quitline Check-Up (QLCU) intervention. Outcomes were collected 90 days post-randomization. Primary outcomes included feasibility and acceptability of delivering the QLCU in the quitline setting. Secondary outcomes included 7-day point prevalence tobacco abstinence, past 30-day cannabis use, and Cannabis Use Disorder Identification Test scores. Results: Study participants were heavy cannabis users, averaging 25 days of use in the past 30; nearly 70% used at a level considered hazardous. Fidelity ratings indicated coaches were successful at delivering the intervention. Treatment engagement was high for both groups (TAU m = 3.4 calls; QLCU m = 3.6 calls) as was treatment satisfaction. Intent-to-treat quit rates (with survey non-responders classified as smokers) were 28.6% for the TAU control group and 24.5% for the QLCU group (P = .45). Discussion: Hazardous cannabis use rates were high in this sample of tobacco cannabis co-users calling quitlines to quit smoking. The intervention for co-users was acceptable and feasible to deliver. No improvements in tobacco cessation outcomes were observed. Pragmatic intervention development within a real-world clinical setting can streamline the intervention development process. More research is needed on tobacco cannabis co-users and who can benefit from a tailored intervention. Registered: ClinicalTrials.gov NCT04737772, February 4, 2021.

The Combined Effects of Nicotine and Cannabis on Cortical Thickness Estimates in Adolescents and Emerging Adults

Early life substance use, including cannabis and nicotine, may result in deleterious effects on the maturation of brain tissue and gray matter cortical development. The current study employed linear regression models to investigate the main and interactive effects of past-year nicotine and cannabis use on gray matter cortical thickness estimates in 11 bilateral independent frontal cortical regions in 223 16-22-year-olds. As the frontal cortex develops throughout late adolescence and young adulthood, this period becomes crucial for studying the impact of substance use on brain structure. The distinct effects of nicotine and cannabis use status on cortical thickness were found bilaterally, as cannabis and nicotine users both had thinner cortices than non-users. Interactions between nicotine and cannabis were also observed, in which cannabis use was associated with thicker cortices for those with a history of nicotine and tobacco product (NTP) use in three left frontal regions. This study sheds light on the intricate relationship between substance use and brain structure, suggesting a potential modulation of cannabis' impact on cortical thickness by nicotine exposure, and emphasizing the need for further longitudinal research to characterize these interactions and their implications for brain health and development.

Prenatal Exposure to Tobacco and Cannabis in Six Race/Ethnicity Groups during the First Three Years after Legalization of Cannabis for Recreational Use in California

There are known health concerns linked to prenatal tobacco and cannabis exposures. This study aims to objectively determine the level of exposure to tobacco and cannabis in pregnant individuals from six race/ethnicity groups (Black, Hispanic, Asian Indian, Native American, Vietnamese, and White) in the first three years following legalization of recreational marijuana use in 2018 in California. We used a cross-sectional sample of prenatal screening program participants (2018-2020) from southern and central California (N = 925). Exposures were estimated by a lab analysis of cotinine (tobacco) and 11-hydroxy-Δ9-tetrahydrocannabinol (OH-THC, cannabis) in banked serum. Disparities in tobacco exposure were evident, with Black subjects experiencing the highest smoking rate (16%) followed by Native American (10%) and White (8%) subjects, and ≤2% among Hispanic, Asian Indian, and Vietnamese subjects. Environmental tobacco exposure generally showed a similar pattern of exposure to tobacco smoking across race/ethnicity groups. Cannabis detection ranged from 5% among Hispanic subjects to 12% and 13% among White and Black subjects, respectively, and was higher among tobacco users and those exposed to environmental tobacco smoke than those with no cotinine detected. Tobacco and cannabis exposure were generally greatest in younger subjects and those with indices of a lower economic status; however, among Black subjects, cannabis exposure was greatest in older subjects and those with a higher socioeconomic status. Race/ethnicity, age, and socioeconomic factors can inform targeting of high-exposure groups for intervention.

Use of the Therapy App Prescinde for Increasing Adherence to Smoking Cessation Treatment

Tobacco use poses major health risks and is a major contributor to causes of death worldwide. Mobile phone-based cessation apps for this substance are gaining popularity, often used as a component of traditional interventions. This study aimed to analyze adherence to an intervention using a mobile phone application (App-therapy Prescinde (v1)) as a function of sociodemographic variables (age, gender, educational level, and profession) as well as the primary activities supported by the app (reducing tobacco or cannabis use and increasing physical exercise). The participants were recruited through the web pages of the Occupational Risk Prevention Service and the Psychology Clinic of the University of Granada during the COVID-19 confinement period. The application's contents include three components (self-report, motivational phrases, and goal setting). Our findings indicate that being male, being aged between 26 and 62, having a high school education, and being unemployed increase the likelihood of adherence to the Prescinde therapy app three months after usage. Our findings highlight the importance of developing new therapeutic approaches and conducting in-depth studies on the factors associated with adherence to tobacco cessation and cannabis cessation treatments via mobile phone applications.

Racial and Ethnic Disparities in Mental Health Problems and Tobacco and Cannabis Use Among US Emerging Adults

INTRODUCTION

Mental health problems in emerging adulthood are linked to tobacco and cannabis use, but whether race and ethnicity modifies these associations is unclear.

METHODS

We used data from wave 4 of the Population Assessment of Tobacco and Health Study (youth n = 6898, young adult n = 10,304) to conduct latent class analysis (LCA) of six past 30-day tobacco and cannabis use indicators (i.e., cigarettes, electronic nicotine delivery systems (ENDS), cigars, blunts, cannabis vaping, other cannabis). We estimated associations between past 30-day internalizing and externalizing (i.e., low (referent), moderate, high) problems and latent classes of tobacco/cannabis use (vs. never/former use) using adjusted multinomial logistic regression. We explored whether associations varied by race and ethnicity through stratification.

RESULTS

We identified four exclusive use latent classes and two dual/poly use latent classes for both youth and young adult samples. Race/ethnicity-stratified models identified associations between internalizing/externalizing problems and most use classes for Hispanic and non-Hispanic White youth/young adults, with mixed results for non-Hispanic Black youth/young adults. For example, Hispanic (OR: 2.50, 95% CI: 1.09-5.74) and non-Hispanic White (OR: 1.90, 95% CI: 1.18-3.06) youth with high internalizing problems had higher odds of ENDS + cannabis vaping. Externalizing problems were not associated with use among non-Hispanic Black youth while internalizing problems were not associated with use among non-Hispanic Black young adults.

CONCLUSION

We observed racial/ethnic variation in mental health problems and tobacco and cannabis use. Understanding mental health problem and tobacco product and cannabis use comorbidity may better inform culturally relevant interventions aimed to prevent and reduce use.

Analysis of postoperative complications related to cannabis and tobacco usage in patients undergoing mandible facial fracture surgeries

BACKGROUND

Cannabis is the third most used controlled substance in the world. Despite its widespread use, minimal research investigates cannabis usage in patients undergoing facial fracture surgeries. This study aimed to evaluate patterns of postoperative complications related to cannabis and tobacco usage after mandible fracture surgeries.

MATERIALS AND METHODS

PearlDiver™, a commercially available healthcare database, was used to identify patients endorsing the use of cannabis, tobacco, or both who underwent mandible fracture surgeries for cross-sectional analysis. The study population was categorized into groups using the Classification of Diseases, 9th revision (ICD-9), ICD-10, and Current Procedural Terminology (CPT) codes. A chi-square analysis was performed to assess the influence of cannabis and tobacco use on postoperative complications.

RESULTS

A total of 8288 patients met the inclusion criteria, with 72 patients with cannabis-only usage, 914 patients with cannabis and tobacco usage, 3236 patients with tobacco-only usage, and 4066 in the control group. For patients using only cannabis, there was not an increased risk of developing postoperative complications compared with the control population. Patients with concurrent cannabis and tobacco usage and those with tobacco-only usage had an increased risk of surgical site infection, facial nonunion, facial abscess, debridement, and malocclusion after surgical repair of mandibular facial fracture.

CONCLUSION

Patients with tobacco-only as well as cannabis and tobacco usage had an increased risk of all postoperative complications, except malocclusion, compared with cannabis-only. Based on the results of this study, it is recommended that healthcare providers consider a patient's history of tobacco use when planning and performing surgical treatment for traumatic mandible fractures.