The co-occurring use and misuse of cannabis and tobacco: a review

Trajectories of polysubstance use: Are past-year internalizing and externalizing problems associated with trajectories of polysubstance use over time?

OBJECTIVE

Polysubstance use among adults has been a public health concern in the U.S. and is associated with adverse consequences. This study aimed to identify the longitudinal trajectory of polysubstance use and test whether internalizing and externalizing problems predict it.

METHODS

Data of adults aged 18 and older (N = 15076) were extracted from the Waves 1-5 Population Assessment of Tobacco and Health Study (2013-2019). Group-Based Trajectory Modeling was performed to identify the trajectory of polysubstance use. Examined substances included use of cigarettes, e-cigarettes, excessive alcohol, cannabis, painkillers, and cocaine in past 30 days from all waves. Weighted multinomial logistic regressions were conducted to investigate the associations between internalizing and externalizing problems and the trajectory of polysubstance use, controlling for demographic variables.

RESULTS

Five trajectory groups were identified: (1) No to minimal polysubstance use risk (45.6 %); (2) Polysubstance use-low risk (10.7 %); (3) Cigarette-leading polysubstance use-high risk (23.5 %); (4) Cigarette-cannabis co-leading polysubstance use-high risk (12.3 %); and (5) Cannabis-leading polysubstance use-high risk (7.8 %). Compared with Group 1, higher internalizing problems predicted the membership of Group 3 [Relative risk ratio (RRR) range: 1.07-1.17] and Group 4 (RRR range: 1.04-1.21). Compared with Group 1, higher externalizing problems predicted the membership of Group 5 (RRR range: 1.01-1.10).

CONCLUSIONS

Prevention efforts should consider internalizing problems and associated trajectories of high-risk polysubstance use (e.g., cigarette-leading and cigarette-cannabis co-leading) as well as externalizing problems and associated trajectories of high-risk polysubstance use (e.g., cannabis-leading), when designing interventions to prevent polysubstance use.

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.

Cannabis policy liberalization is only associated with increased blunt use if states lack strong tobacco control

INTRODUCTION

Co-use of tobacco and cannabis has long been an issue for prevention and intervention efforts targeting these substances. Blunt use-cannabis inside a cigar wrapper-has been a consistent mode of cannabis consumption since the 1990s. Since then, both tobacco control and cannabis policies have changed considerably. This paper examines the influence of tobacco taxes and smoke-free policies as well as medical and recreational cannabis policies on blunt use among young people.

METHODS

Combining state-level tobacco control and cannabis policy data with the restricted-access youth cohort of the Population Assessment of Tobacco and Health (PATH) study, we use multilevel logistic regression models to examine the impact of these policies on past-year blunt use.

RESULTS

While we found a main effect whereby both legal medical and recreational cannabis policies are associated with higher odds of blunt use among youth, interaction effects demonstrate that this association only emerges in states lacking a comprehensive tobacco smoke-free policy. In states with smoke-free policies, we found no significant associations between cannabis policy and odds of blunt use.

CONCLUSIONS

Denormalization through smoke-free policies may mitigate the effects of recreational and medical cannabis policies on blunt use. Smoke-free policies represent a possible cost-effective mechanism to curb the co-use of tobacco and cannabis in the form of blunts. States with medical and recreational cannabis policies may benefit from greater prevention efforts for young people specifically focused on blunt use, especially in states that do not have strong tobacco control.

Cross-ancestry genetic investigation of schizophrenia, cannabis use disorder, and tobacco smoking

Individuals with schizophrenia frequently experience co-occurring substance use, including tobacco smoking and heavy cannabis use, and substance use disorders. There is interest in understanding the extent to which these relationships are causal, and to what extent shared genetic factors play a role. We explored the relationships between schizophrenia (Scz; European ancestry N = 161,405; African ancestry N = 15,846), cannabis use disorder (CanUD; European ancestry N = 886,025; African ancestry N = 120,208), and ever-regular tobacco smoking (Smk; European ancestry N = 805,431; African ancestry N = 24,278) using the largest available genome-wide studies of these phenotypes in individuals of African and European ancestries. All three phenotypes were positively genetically correlated (rgs = 0.17-0.62). Genetic instrumental variable analyses suggested the presence of shared heritable factors, but evidence for bidirectional causal relationships was also found between all three phenotypes even after correcting for these shared genetic factors. We identified 327 pleiotropic loci with 439 lead SNPs in the European ancestry data, 150 of which were novel (i.e., not genome-wide significant in the original studies). Of these pleiotropic loci, 202 had lead variants which showed convergent effects (i.e., same direction of effect) on Scz, CanUD, and Smk. Genetic variants convergent across all three phenotypes showed strong genetic correlations with risk-taking, executive function, and several mental health conditions. Our results suggest that both shared genetic factors and causal mechanisms may play a role in the relationship between CanUD, Smk, and Scz, but longitudinal, prospective studies are needed to confirm a causal relationship.

Blunt Talk on "Blunts": The Increasingly Popular Tobacco Product That Is Potentially Exacerbating Tobacco-Related Health Disparities

A "blunt" is a hollowed-out cigar/cigarillo from which much of the loose tobacco has been removed, and the remaining tobacco wrapper filled with cannabis. Although blunts contain significant levels of tobacco/nicotine, they are often treated as if they were exclusive cannabis products and omitted from surveys of tobacco products. Whereas the prevalence of virtually all other tobacco products is on the decline in the USA, available data suggest that the prevalence of blunt smoking is not - and in fact, it may be increasing. Blunts are most frequently used by people who self-identify as Black. As a result of misperceptions and perhaps biases, there is a dearth of scientific investigation, hence knowledge, surrounding the health effects associated with blunt smoking. Co-use of tobacco and cannabis has been reported to have additive and even synergistic adverse health effects. Lack of investigations into the health effects of tobacco products most frequently used by Black people may contribute to tobacco-related health disparities. We argue that the scientific and public health communities must treat blunts as the potentially lethal tobacco product that they are, studying their prevalence and use patterns, and investigating their adverse health effects, both short and long term.

A robust brain network for sustained attention from adolescence to adulthood that predicts later substance use

Substance use, including cigarettes and cannabis, is associated with poorer sustained attention in late adolescence and early adulthood. Previous studies were predominantly cross-sectional or under-powered and could not indicate if impairment in sustained attention was a predictor of substance use or a marker of the inclination to engage in such behavior. This study explored the relationship between sustained attention and substance use across a longitudinal span from ages 14 to 23 in over 1000 participants. Behaviors and brain connectivity associated with diminished sustained attention at age 14 predicted subsequent increases in cannabis and cigarette smoking, establishing sustained attention as a robust biomarker for vulnerability to substance use. Individual differences in network strength relevant to sustained attention were preserved across developmental stages and sustained attention networks generalized to participants in an external dataset. In summary, brain networks of sustained attention are robust, consistent, and able to predict aspects of later substance use.

A Bivariate Twin Study of Lifetime cannabis Initiation and Lifetime Regular Tobacco Smoking Across Three Different Countries

Regular cigarette smoking and cannabis consumption are strongly positively related to each other, yet few studies explore their underlying variation and covariation. We evaluated the genetic and environmental decomposition of variance and covariance of these two traits in twin data from three countries with different social norms and legislation. Data from the Netherlands Twin Register, FinnTwin12/16, and the Minnesota Center for Twin Family Research (total N = 21,617) were analyzed in bivariate threshold models of lifetime regular smoking initiation (RSI) and lifetime cannabis initiation (CI). We ran unstratified models and models stratified by sex and country. Prevalence of RSI was lowest in the Netherlands and prevalence of CI was highest in Minnesota. In the unstratified model, genetic (A) and common environmental factors (C) contributed substantially to the liabilities of RSI (A = 0.47, C = 0.34) and CI (A = 0.28, C = 0.51). The two liabilities were significantly phenotypically (rP = 0.56), genetically (rA = 0.74), and environmentally correlated in the unstratified model (rC = 0.47and rE = 0.48, representing correlations between common and unique environmental factors). The magnitude of phenotypic correlation between liabilities varied by country but not sex (Minnesota rP ~ 0.70, Netherlands rP ~ 0.59, Finland rP ~ 0.45). Comparisons of decomposed correlations could not be reliably tested in the stratified models. The prevalence and association of RSI and CI vary by sex and country. These two behaviors are correlated because there is genetic and environmental overlap between their underlying latent liabilities. There is heterogeneity in the genetic architecture of these traits across country.

The association of tobacco smoking and metabolite levels in the anterior cingulate cortex of first-episode psychosis patients: A case-control and 6-month follow-up 1H-MRS study

Tobacco smoking is highly prevalent among patients with psychosis and associated with worse clinical outcomes. Neurometabolites, such as glutamate and choline, are both implicated in psychosis and tobacco smoking. However, the specific associations between smoking and neurometabolites have yet to be investigated in patients with psychosis. The current study examines associations of chronic smoking and neurometabolite levels in the anterior cingulate cortex (ACC) in first-episode psychosis (FEP) patients and controls. Proton magnetic resonance spectroscopy (1H MRS) data of 59 FEP patients and 35 controls were analysed. Associations between smoking status (i.e., smoker yes/no) or cigarettes per day and Glx (glutamate + glutamine, as proxy for glutamate) and total choline (tCh) levels were assessed at baseline in both groups separately. For patients, six months follow-up data were acquired for multi-cross-sectional analysis using linear mixed models. No significant differences in ACC Glx levels were found between smoking (n = 28) and non-smoking (n = 31) FEP patients. Smoking patients showed lower tCh levels compared to non-smoking patients at baseline, although not surving multiple comparisons correction, and in multi-cross-sectional analysis (pFDR = 0.08 and pFDR = 0.044, respectively). Negative associations were observed between cigarettes smoked per day, and ACC Glx (pFDR = 0.02) and tCh levels (pFDR = 0.02) in controls. Differences between patients and controls regarding Glx might be explained by pre-existing disease-related glutamate deficits or alterations at nicotine acetylcholine receptor level, resulting in differences in tobacco-related associations with neurometabolites. Additionally, observed alterations in tCh levels, suggesting reduced cellular proliferation processes, might result from exposure to the neurotoxic effects of smoking.

Genetic influences and causal pathways shared between cannabis use disorder and other substance use traits

Cannabis use disorder (CanUD) has increased with the legalization of the use of cannabis. Around 20% of individuals using cannabis develop CanUD, and the number of users has grown with increasing ease of access. CanUD and other substance use disorders (SUDs) are associated phenotypically and genetically. We leveraged new CanUD genomics data to undertake genetically-informed analyses with unprecedented power, to investigate the genetic architecture and causal relationships between CanUD and lifetime cannabis use with risk for developing SUDs and substance use traits. Analyses included calculating local and global genetic correlations, genomic structural equation modeling (genomicSEM), and Mendelian Randomization (MR). Results from the genetic correlation and genomicSEM analyses demonstrated that CanUD and cannabis use differ in their relationships with SUDs and substance use traits. We found significant causal effects of CanUD influencing all the analyzed traits: opioid use disorder (OUD) (Inverse variant weighted, IVW β = 0.925 ± 0.082), problematic alcohol use (PAU) (IVW β = 0.443 ± 0.030), drinks per week (DPW) (IVW β = 0.182 ± 0.025), Fagerström Test for Nicotine Dependence (FTND) (IVW β = 0.183 ± 0.052), cigarettes per day (IVW β = 0.150 ± 0.045), current versus former smokers (IVW β = 0.178 ± 0.052), and smoking initiation (IVW β = 0.405 ± 0.042). We also found evidence of bidirectionality showing that OUD, PAU, smoking initiation, smoking cessation, and DPW all increase risk of developing CanUD. For cannabis use, bidirectional relationships were inferred with PAU, smoking initiation, and DPW; cannabis use was also associated with a higher risk of developing OUD (IVW β = 0.785 ± 0.266). GenomicSEM confirmed that CanUD and cannabis use load onto different genetic factors. We conclude that CanUD and cannabis use can increase the risk of developing other SUDs. This has substantial public health implications; the move towards legalization of cannabis use may be expected to increase other kinds of problematic substance use. These harmful outcomes are in addition to the medical harms associated directly with CanUD.

Bidirectional relationships between pain and patterns of cannabis and tobacco use in a US nationally representative sample

ABSTRACT

One-fifth of US adults experience chronic pain, which is associated with increased tobacco and cannabis use. Although bidirectional relationships between tobacco and pain have been demonstrated, pathways between pain, cannabis use, and co-use of cannabis and tobacco are understudied. We aimed to estimate the effects of (1) substance use (exclusive and co-use of cannabis and tobacco) on later pain intensity, and (2) pain intensity on later substance use. Data were from 31,983 adults in biennial surveys (2015-2021) of the US nationally representative longitudinal Population Assessment of Tobacco and Health Study (n = 71,055 pairs of consecutive surveys; T1 and T2). Past-week pain intensity was dichotomized (≤4/10 no/low pain; >4/10 moderate/severe pain). Mutually exclusive substance use categories (past 30 days) were no cannabis/tobacco use; exclusive cannabis/tobacco use; and co-use. Logistic regression assessed whether T1 substance use affected moderate/severe pain at T2. Multinomial models assessed whether pain status at T1 affected substance use at T2. Compared with no cannabis/tobacco use at T1, co-use (OR: 2.29 [95% CI: 2.09-2.51]), exclusive tobacco use (2.00 [1.86-2.14]), and exclusive cannabis use (1.35 [1.13-1.61]) were all associated with moderate/severe pain at T2. Moderate/severe pain at T1 increased odds of co-use (2.43 [2.22-2.66]), exclusive tobacco (2.12 [1.98-2.28]), and exclusive cannabis use (1.46 [1.29-1.65]) compared with no cannabis/tobacco use at T2, and increased odds of co-use at T2 compared with exclusive cannabis/tobacco use. Findings demonstrated bidirectional relationships between pain and the exclusive use and co-use of cannabis and tobacco and indicate potential synergy in the co-use of cannabis and tobacco with respect to pain.

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.

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.

Neurological Complications of Cannabinoids

Cannabinoid use, particularly for recreational purposes, is increasing exponentially across all age groups, especially in younger populations, due to its perceived low risk and legalization. While cannabinoids may be largely considered as safe, there is mounting evidence of increased risk of systemic and neurological complications through their interaction with the poorly understood endocannabinoid receptor network within the central nervous system and other organ systems. Acute cannabinoid exposure can cause neuropsychiatric symptoms in addition to altering cerebral blood flow, leading to cerebrovascular complications such as ischemic stroke, subarachnoid hemorrhage, and reversible cerebral vasoconstriction syndrome (RCVS). Chronic use, particularly among adolescents, may be associated with increased risk of long-term cognitive deficits, schizophrenia, and other neuropsychiatric effects. Synthetic cannabinoids have increased potency, with reports of causing profound neurological complications including coma, seizures, posterior reversible encephalopathy syndrome, and RCVS. Despite increasing evidence, the quality of literature describing neurologic complications with cannabinoids remains limited to case series and retrospective cohort studies, with significant confounding factors such as concomitant use of other illicit drugs, limiting interpretation. In this review, we summarize the effect of cannabinoids on the neurologic system and associated neurological complications.

Association of Semaglutide With Tobacco Use Disorder in Patients With Type 2 Diabetes : Target Trial Emulation Using Real-World Data

BACKGROUND

Reports of reduced desire to smoke in patients treated with semaglutide, a glucagon-like peptide receptor agonist (GLP-1RA) medication for type 2 diabetes mellitus (T2DM) and obesity, have raised interest about its potential benefit for tobacco use disorders (TUDs).

OBJECTIVE

To examine the association of semaglutide with TUD-related health care measures in patients with comorbid T2DM and TUD.

DESIGN

Emulation target trial based on a nationwide population-based database of patient electronic health records.

SETTING

United States, 1 December 2017 to 31 March 2023.

PARTICIPANTS

Seven target trials were emulated among eligible patients with comorbid T2DM and TUD by comparing the new use of semaglutide versus 7 other antidiabetes medications (insulins, metformin, dipeptidyl-peptidase-4 inhibitors, sodium-glucose cotransporter-2 inhibitors, sulfonylureas, thiazolidinediones, and other GLP-1RAs).

MEASUREMENTS

The TUD-related health care measures (medical encounter for diagnosis of TUD, smoking cessation medication prescriptions, and smoking cessation counseling) that occurred within a 12-month follow-up were examined using Cox proportional hazards and Kaplan-Meier survival analyses.

RESULTS

The study compared 222 942 new users of antidiabetes medications including 5967 of semaglutide. Semaglutide was associated with a significantly lower risk for medical encounters for TUD diagnosis compared with other antidiabetes medications, and was strongest compared with insulins (hazard ratio [HR], 0.68 [95% CI, 0.63 to 0.74]) and weakest but statistically significant compared with other GLP-1RAs (HR, 0.88 [CI, 0.81 to 0.96]). Semaglutide was associated with reduced smoking cessation medication prescriptions and counseling. Similar findings were observed in patients with and without a diagnosis of obesity. For most of the group comparisons, the differences occurred within 30 days of prescription initiation.

LIMITATION

Documentation bias, residual confounding, missing data on current smoking behavior, body mass index, and medication adherence.

CONCLUSION

Semaglutide was associated with lower risks for TUD-related health care measures in patients with comorbid T2DM and TUD compared with other antidiabetes medications including other GLP-1Ras, primarily within 30 days of prescription. These findings suggest the need for clinical trials to evaluate semaglutide's potential for TUD treatment.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Significant Psychedelic Experiences Evaluated for Mystical Characteristics Associated with Cannabis Use Reduction and Psychological Flexibility Improvement: A Naturalistic Cross-Sectional Retrospective Survey

Treating cannabis use disorder remains a significant challenge in the field of addiction medicine. Some recent studies point to psychedelic-assisted psychotherapy as a potential treatment option for substance use disorders. The objective of this study was therefore to explore the impact of naturalistic psychedelic experiences on cannabis use and psychological flexibility. An online retrospective survey was carried out on 152 cannabis users who also reported a significant experience induced by psychedelics in the past. Following a psychedelic experience, there was a significant and sustained reduction of average CUDIT score (p < .001), frequency of cannabis use (p < .001), and acute duration of daily intoxication (p < .001). Cannabis use reduction during the first month post-experience was significantly associated with the intensity of the mystical experience (p = .01). Participants reported a concomitant increased lasting improvement of psychological flexibility following the experience (p < .001), which was correlated to the intensity of the mystical experience during the first month post-experience (p = .04). This study demonstrates that naturalistic psychedelic experiences may be followed by a decrease in cannabis use. Positive health outcomes appear potentially connected to the intensity of the mystical experience, as well as an improvement in psychological flexibility.

Does smoking cessation reduce other substance use, psychiatric symptoms, and pain symptoms? Results from an emulated hypothetical randomized trial of US veterans

BACKGROUND

Quitting smoking may lead to improvement in substance use, psychiatric symptoms, and pain, especially among high-risk populations who are more likely to experience comorbid conditions. However, causal inferences regarding smoking cessation and its subsequent benefits have been limited.

METHODS

We emulated a hypothetical open-label randomized control trial of smoking cessation using longitudinal observational data of HIV-positive and HIV-negative US veterans from 2003-2015 in the Veterans Aging Cohort Study. We followed individuals from the first time they self-reported current cigarette smoking (baseline). We categorized participants as quitters or non-quitters at the first follow-up visit (approximately 1 year after baseline). Using inverse probability weighting to adjust for confounding and selection bias, we estimated odds ratios for improvement of co-occurring conditions (unhealthy alcohol use, cannabis use, illicit opioid use, cocaine use, depressive symptoms, anxiety symptoms, and pain symptoms) at second follow-up (approximately 2 years after baseline) for those who quit smoking compared to those who did not, among individuals who had the condition at baseline.

RESULTS

Of 4,165 eligible individuals (i.e., current smokers at baseline), 419 reported no current smoking and 2,330 reported current smoking at the first follow-up. Adjusted odds ratios (95% confidence intervals) for associations between quitting smoking and improvement of each condition at second follow-up were: 2.10 (1.01, 4.35) for unhealthy alcohol use, 1.75 (1.00, 3.06) for cannabis use, 1.10 (0.58, 2.08) for illicit opioid use, and 2.25 (1.20, 4.24) for cocaine use, 0.78 (0.44, 1.38) for depressive symptoms, 0.93 (0.58, 1.49) for anxiety symptoms, and 1.31 (0.84, 2.06) for pain symptoms.

CONCLUSIONS

While a causal interpretation of our findings may not be warranted, we found evidence for decreased substance use among veterans who quit cigarette smoking but none for the resolution of psychiatric conditions or pain symptoms. Findings suggest the need for additional resources combined with smoking cessation to reduce psychiatric and pain symptoms for high-risk populations.

A robust brain network for sustained attention from adolescence to adulthood that predicts later substance use

Substance use, including cigarettes and cannabis, is associated with poorer sustained attention in late adolescence and early adulthood. Previous studies were predominantly cross-sectional or under-powered and could not indicate if impairment in sustained attention was a predictor of substance-use or a marker of the inclination to engage in such behaviour. This study explored the relationship between sustained attention and substance use across a longitudinal span from ages 14 to 23 in over 1,000 participants. Behaviours and brain connectivity associated with diminished sustained attention at age 14 predicted subsequent increases in cannabis and cigarette smoking, establishing sustained attention as a robust biomarker for vulnerability to substance use. Individual differences in network strength relevant to sustained attention were preserved across developmental stages and sustained attention networks generalized to participants in an external dataset. In summary, brain networks of sustained attention are robust, consistent, and able to predict aspects of later substance use.

Genome-wide association studies of lifetime and frequency cannabis use in 131,895 individuals

Cannabis is one of the most widely used drugs globally. Decriminalization of cannabis is further increasing cannabis consumption. We performed genome-wide association studies (GWASs) of lifetime (N=131,895) and frequency (N=73,374) of cannabis use. Lifetime cannabis use GWAS identified two loci, one near CADM2 (rs11922956, p=2.40E-11) and another near GRM3 (rs12673181, p=6.90E-09). Frequency of use GWAS identified one locus near CADM2 (rs4856591, p=8.10E-09; r2 =0.76 with rs11922956). Both traits were heritable and genetically correlated with previous GWASs of lifetime use and cannabis use disorder (CUD), as well as other substance use and cognitive traits. Polygenic scores (PGSs) for lifetime and frequency of cannabis use associated cannabis use phenotypes in AllofUs participants. Phenome-wide association study of lifetime cannabis use PGS in a hospital cohort replicated associations with substance use and mood disorders, and uncovered associations with celiac and infectious diseases. This work demonstrates the value of GWASs of CUD transition risk factors.

The Association Between Chronic Tobacco Smoking and Brain Alterations in Schizophrenia: A Systematic Review of Magnetic Resonance Imaging Studies

BACKGROUND AND HYPOTHESIS

The high co-occurrence of tobacco smoking in patients with schizophrenia spectrum disorders (SSD) poses a serious health concern, linked to increased mortality and worse clinical outcomes. The mechanisms underlying this co-occurrence are not fully understood.

STUDY DESIGN

Addressing the need for a comprehensive overview of the impact of tobacco use on SSD neurobiology, we conducted a systematic review of neuroimaging studies (including structural, functional, and neurochemical magnetic resonance imaging studies) that investigate the association between chronic tobacco smoking and brain alterations in patients with SSD.

STUDY RESULTS

Eight structural and fourteen functional studies were included. Structural studies show widespread independent and additive reductions in gray matter in relation to smoking and SSD. The majority of functional studies suggest that smoking might be associated with improvements in connectivity deficits linked to SSD. However, the limited number of and high amount of cross-sectional studies, and high between-studies sample overlap prevent a conclusive determination of the nature and extent of the impact of smoking on brain functioning in patients with SSD. Overall, functional results imply a distinct neurobiological mechanism for tobacco addiction in patients with SSD, possibly attributed to differences at the nicotinic acetylcholine receptor level.

CONCLUSIONS

Our findings highlight the need for more longitudinal and exposure-dependent studies to differentiate between inherent neurobiological differences and the (long-term) effects of smoking in SSD, and to unravel the complex interaction between smoking and schizophrenia at various disease stages. This could inform more effective strategies addressing smoking susceptibility in SSD, potentially improving clinical outcomes.

Cannabis Use Disorder Symptoms in Weekly Cannabis Users: A Network Comparison Between Daily Cigarette Users and Nondaily Cigarette Users

Background: Concurrent use (co-use) of cannabis and tobacco is common and associated with worse clinical outcomes compared with cannabis use only. The mechanisms and interactions of cannabis use disorder (CUD) symptoms underlying co-use remain poorly understood. Methods: We examined differences in the symptom presence and symptom network configurations between weekly cannabis users who use tobacco daily (co-users, n=789) or non- or nondaily (nondaily co-users, n=428). Results: First, we identified a range of symptoms (craving, failed reduce or quit attempts, neglected responsibilities, and negative social effects) that are most central to the highly interconnected CUD symptom network. Risky cannabis use was mostly associated with negative social and health effects, and independent of other CUD symptoms. Craving symptoms act as a bridge between different CUD and withdrawal symptoms. Among co-users, (1) craving is more strongly associated with negative psychosocial effects, (2) feelings of depression and negative health effects are more central to the network, and (3) the negative health effects are more strongly associated with failed attempts to reduce or quit attempts compared with nondaily co-users. Discussion: Our results go beyond existing findings focused on the mere increase in CUD symptom presence, and speak to the potential synergistic effects of co-use on dependence and withdrawal symptoms. We outline clinical implications with respect to targeting specific CUD symptoms in co-users, and point to future research to disentangle tobacco and cannabis craving symptoms.

Multi-ancestry meta-analysis of tobacco use disorder identifies 461 potential risk genes and reveals associations with multiple health outcomes

Tobacco use disorder (TUD) is the most prevalent substance use disorder in the world. Genetic factors influence smoking behaviours and although strides have been made using genome-wide association studies to identify risk variants, most variants identified have been for nicotine consumption, rather than TUD. Here we leveraged four US biobanks to perform a multi-ancestral meta-analysis of TUD (derived via electronic health records) in 653,790 individuals (495,005 European, 114,420 African American and 44,365 Latin American) and data from UK Biobank (ncombined = 898,680). We identified 88 independent risk loci; integration with functional genomic tools uncovered 461 potential risk genes, primarily expressed in the brain. TUD was genetically correlated with smoking and psychiatric traits from traditionally ascertained cohorts, externalizing behaviours in children and hundreds of medical outcomes, including HIV infection, heart disease and pain. This work furthers our biological understanding of TUD and establishes electronic health records as a source of phenotypic information for studying the genetics of TUD.

A multi-ancestry cerebral cortex transcriptome-wide association study identifies genes associated with smoking behaviors

Transcriptome-wide association studies (TWAS) have provided valuable insight in identifying genes that may impact cigarette smoking. Most of previous studies, however, mainly focused on European ancestry. Limited TWAS studies have been conducted across multiple ancestries to explore genes that may impact smoking behaviors. In this study, we used cis-eQTL data of cerebral cortex from multiple ancestries in MetaBrain, including European, East Asian, and African samples, as reference panels to perform multi-ancestry TWAS analyses on ancestry-matched GWASs of four smoking behaviors including smoking initiation, smoking cessation, age of smoking initiation, and number of cigarettes per day in GWAS & Sequencing Consortium of Alcohol and Nicotine use (GSCAN). Multiple-ancestry fine-mapping approach was conducted to identify credible gene sets associated with these four traits. Enrichment and module network analyses were further performed to explore the potential roles of these identified gene sets. A total of 719 unique genes were identified to be associated with at least one of the four smoking traits across ancestries. Among those, 249 genes were further prioritized as putative causal genes in multiple ancestry-based fine-mapping approach. Several well-known smoking-related genes, including PSMA4, IREB2, and CHRNA3, showed high confidence across ancestries. Some novel genes, e.g., TSPAN3 and ANK2, were also identified in the credible sets. The enrichment analysis identified a series of critical pathways related to smoking such as synaptic transmission and glutamate receptor activity. Leveraging the power of the latest multi-ancestry GWAS and eQTL data sources, this study revealed hundreds of genes and relevant biological processes related to smoking behaviors. These findings provide new insights for future functional studies on smoking behaviors.

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.

A national study of clinical discussions about cannabis use among Veteran patients prescribed opioids

BACKGROUND

The Veterans Health Administration tracks urine drug tests (UDTs) among patients on long-term opioid therapy (LTOT) and recommends discussing the health effects of cannabis use.

OBJECTIVE

To determine the occurrence of cannabis-related discussions between providers and patients on LTOT during six months following UDT positive for cannabis, and examine factors associated with documenting cannabis use.

DESIGN

We identified patients prescribed LTOT with a UDT positive for cannabis in 2019. We developed a text-processing tool to extract discussions around cannabis use from their charts.

SUBJECTS

Twelve thousand seventy patients were included. Chart review was conducted on a random sample of 1,946 patients.

MAIN MEASURES

The presence of a cannabis term in the chart suggesting documented cannabis use or cannabis-related discussions. Content of those discussions was extracted in a subset of patients. Logistic regression was used to examine the association between patient factors, including state of residence legal status, with documentation of cannabis use.

KEY RESULTS

Among the 12,070 patients, 65.8% (N = 7,948) had a cannabis term, whereas 34.1% (N = 4,122) of patients lacked a cannabis term, suggesting that no documentation of cannabis use or discussion between provider and patient took place. Among the subset of patients who had a discussion documented, 47% related to cannabis use for medical reasons, 35% related to a discussion of VA policy or legal issues, and 17% related to a discussion specific to medical risks or harm reduction strategies. In adjusted analyses, residents of states with legalized recreational cannabis were less likely to have any cannabis-related discussion compared to patients in non-legal states [OR 0.73, 95% CI 0.64-0.82].

CONCLUSIONS

One-third of LTOT patients did not have documentation of cannabis use in the chart in the 6 months following a positive UDT for cannabis. Discussions related to the medical risks of cannabis use or harm reduction strategies were uncommon.

Cross-Substance Associations With Transitions in Cannabis and Nicotine Use in a Statewide Sample of Young Adults in Washington State

OBJECTIVE

Understanding transitions in nicotine and cannabis use has implications for prevention and efforts to reduce harmful use. Focusing on cross-substance associations, we examined how use of one substance was associated with year-to-year transitions in frequency of use of the other among young adults in the context of legalized nonmedical cannabis.

METHOD

A statewide sample from Washington (N = 4,039; ages 18-25 at baseline) provided up to 3 years of annual data on past-month cannabis use and nicotine use (tobacco cigarettes and e-cigarettes/vaping). Manifest Markov models examined how use of each substance was associated with transitions in the other across categories of past-month no use, occasional use (1-19 days), and frequent use (≥20 days).

RESULTS

Occasional and frequent nicotine use (vs. no use) predicted higher probability of transitioning from no cannabis use to occasional or frequent cannabis use and from occasional use to frequent use, whereas associations with cessation and de-escalation were inconsistent in direction, small in magnitude, and not statistically significant. Cannabis use positively predicted onset of nicotine use, and associations of cannabis use with escalation from occasional to frequent nicotine use, de-escalation in use, and cessation in use were small and inconsistent in direction.

CONCLUSIONS

The findings corroborate prior research on cannabis and nicotine use as risk factors to address in prevention efforts. The findings do not provide strong support for prioritization of dual abstinence in efforts to encourage reductions in or cessation of cannabis or nicotine use among young adults.

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.

Simultaneous Cannabis and Alcohol Use among Medical Cannabis Patients

Background: During the past two decades of cannabis legalization, the prevalence of medical cannabis (MC) use has increased and there has also been an upward trend in alcohol consumption. As less restricted cannabis laws generate more adult cannabis users, there is concern that more individuals may be simultaneously using medical cannabis with alcohol. A few studies have examined simultaneous use of medical cannabis with alcohol, but none of those studies also assessed patients' current or previous non-medical cannabis use. This paper explores simultaneous alcohol and medical cannabis use among medical cannabis patients with a specific focus on previous history of cannabis use and current non-medical cannabis use. Methods: A retrospective cohort study of MC patients (N = 319) from four dispensaries located in New York. Bivariate chi-square tests and multivariable logistic regression are used to estimate the extent to which sociodemographic and other factors were associated with simultaneous use. Results: Approximately 29% of the sample engaged in simultaneous use and a large share of these users report previous (44%) or current (66%) use of cannabis for non-medical purposes. MC patients who either previously or currently use cannabis non-medicinally, men, and patients using MC to treat a pain-related condition, were significantly more likely to report simultaneous alcohol/MC use. Conclusions: Findings indicate that there may be differential risks related to alcohol/MC use, which should be considered by cannabis regulatory policies and prevention/treatment programs. If patients are using cannabis and/or alcohol to manage pain, clinicians should screen for both alcohol and cannabis use risk factors.

Cannabis reduction among adolescents as spillover from successful tobacco control

BACKGROUND

National programs that reduce adolescent cannabis use warrant renewed attention in light of current discussions to reform cannabis legislation, including the possibility of legalization for recreational use. This study measures the size of a decrease in a country's prevalence of adolescent cannabis use that accompanies a decrease in its prevalence of adolescents who had ever smoked a cigarette.

METHODS

Data are from the European School Survey Project on Alcohol and Other Drugs (ESPAD), which is a collaborative effort of more than 40 European countries to surveil adolescent substance use. This study uses data from the seven survey administrations in 1995, 1999, 2003, 2007, 2011, 2015, and 2019. The main analysis is a fixed-effect regression analysis of country-level, four-year changes in adolescent lifetime cannabis use prevalence on country-level, four-year changes in adolescent lifetime cigarette use prevalence.

RESULTS

Decreases in the national prevalence of adolescents who had ever smoked a cigarette were accompanied by decreases half as large in national prevalence of adolescent lifetime cannabis use.

CONCLUSION

For European countries considering the legalization of adult recreational cannabis use, tobacco control can offer a tool to help counter potential increases in cannabis use among adolescents.

A preliminary characterization of cannabis oil use and vaporization among individuals who use for medical purposes: A pilot study

Little is known about the naturalistic use of cannabis oil vaporization, a high-potency product with the ability to be administered discreetly. This pilot study evaluated the feasibility of utilizing a "smart" vaporizer and application to assess the timing, frequency, socioenvironmental factors, and substance use involved in cannabis oil vaporization. Adults with a medical cannabis registration card were recruited from a dispensary in Rhode Island and completed a 2-week study monitoring period using the Gram1 vaporizer, followed by a poststudy qualitative interview. The sample included nine adults who were predominantly male (89%), 100% White, and 100% non-Hispanic. The Gram1 collected topographical vaping data, and the cellphone application utilized ecological momentary assessment (EMA) to assess socioenvironmental factors and other substance use. Qualitative interview data were coded, and illustrative quotations were selected to support quantitative findings. A total of 224 vaping sessions were recorded reflecting 76.4% of the study monitoring period. There was an average of 1.79 vaping sessions per day across all days. Participants took 8.76 puffs on average (SD = 8.23) per vaping session, and the session lasted 2.59 min on average (SD = 4.19). Regular vaporization was exhibited across days of the week and hours of the day. EMA reports indicated that smoking cannabis flower was the most common additional mode of cannabis administration. This study utilized a naturalistic design with novel topographical data and EMA to characterize cannabis oil vaporization. These findings establish the feasibility of collecting objective, momentary data to better understand use behaviors which are critical to informing safe consumption. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Cannabis Use in Germany

BACKGROUND

The federal government of Germany is planning to liberalize the recreational cannabis market for adults. We aimed to collect key baseline data on frequency of use, routes of administration, and co-use of cannabis and inhaled nicotine or tobacco products in the population.

METHODS

Based on data from a national survey of 9644 people aged >14 years, we analyzed self-reported use of cannabis in the past 12 months and preferred route of administration (single choice: smoked with tobacco; smoked without tobacco; inhaled without tobacco; consumed with food; consumed in another form).

RESULTS

The prevalence of past-year cannabis use was 4.6% (95% CI [4,2; 5,1%]), with higher rates among 14-24- (11.4%) and 25-39-year-olds (8.2%) as well as among co-users of inhaled nicotine or tobacco products, particularly waterpipe users (27.0%). Smoking cannabis with or without tobacco was the preferred route of administration, reported by 92.4% (95% CI [89,6; 94,6%]). It was most frequently reported by 14-24-year-olds and by co-users of inhaled nicotine or tobacco products.

CONCLUSION

Smoking remains the predominant form of using cannabis-especially among younger users, who are at greatest risk of cannabis-related consequences. The true prevalence of cannabis use may have been underestimated in our study, however, as not all participants answered the questions on cannabis. Nevertheless, preventive and harm reduction efforts are needed to reduce the harm from using cannabis. Continuous monitoring is required to evaluate the effects of the forthcoming law changes in Germany.

Cross-ancestry genetic investigation of schizophrenia, cannabis use disorder, and tobacco smoking

Individuals with schizophrenia frequently experience co-occurring substance use, including tobacco smoking and heavy cannabis use, and substance use disorders. There is interest in understanding the extent to which these relationships are causal, and to what extent shared genetic factors play a role. We explored the relationships between schizophrenia (Scz), cannabis use disorder (CanUD), and ever-regular tobacco smoking (Smk) using the largest available genome-wide studies of these phenotypes in individuals of African and European ancestries. All three phenotypes were positively genetically correlated (rgs = 0.17 - 0.62). Causal inference analyses suggested the presence of horizontal pleiotropy, but evidence for bidirectional causal relationships was also found between all three phenotypes even after correcting for horizontal pleiotropy. We identified 439 pleiotropic loci in the European ancestry data, 150 of which were novel (i.e., not genome-wide significant in the original studies). Of these pleiotropic loci, 202 had lead variants which showed convergent effects (i.e., same direction of effect) on Scz, CanUD, and Smk. Genetic variants convergent across all three phenotypes showed strong genetic correlations with risk-taking, executive function, and several mental health conditions. Our results suggest that both horizontal pleiotropy and causal mechanisms may play a role in the relationship between CanUD, Smk, and Scz, but longitudinal, prospective studies are needed to confirm a causal relationship.

First Used Nicotine/Cannabis Product and Associated Outcomes in Late Adolescents

BACKGROUND

Nicotine and tobacco product (NTP) and cannabis use are common in adolescence/young adulthood and increase risk for negative psychosocial outcomes. This study investigated associations among adolescent/young adults' initial experiences with NTPs, lifetime frequency of substance use, substance-related problems, and mental health symptoms.

METHOD

Adolescents and young adults enrolled in a study on NTP and cannabis use were asked at what age they initiated the use of NTPs and were assigned to groups based on which product or substance(s) they reported using at the earliest age. Participants who reported use of NTPs (in isolation, without cannabis) first (N = 78, "NTP-only"), simultaneous use of NTPs and cannabis first (e.g., blunt or bowl; N = 25, "Simult-only"), use of both NTPs in isolation and simultaneous use at the same age (N = 48, "NTP + Simult"), and no NTP use (N = 53, "NTP-naïve") were compared on substance use, substance-related problems, and mental health symptoms.

RESULTS

Groups differed on lifetime frequency of NTP, simultaneous, and cannabis use, with NTP users reporting more substance use episodes and substance-related problems than the NTP-naïve group. The lifetime frequency of cannabis use did not differ across NTP use groups. NTP use was associated with increased anxiety and depression, with no significant differences between groups.

CONCLUSIONS

Adolescents and young adults who use nicotine may be at increased risk for greater nicotine use and mental health consequences, but initiating NTP use simultaneously with cannabis may not increase the risk of negative outcomes above and beyond nicotine initiation. Prospective longitudinal research is needed to establish temporal associations between first-used NTP/cannabis products and relevant outcomes.

Cannabis cravings predict cigarette use in schizophrenia: a secondary analysis from two cannabis abstinence studies

CLINICAL TRIAL NAME

Effects of Repetitive Transcranial Magnetic Stimulation (rTMS) on Cannabis Use and Cognitive Outcomes in SchizophreniaURL: www.clinicaltrials.gov; Registration Number: NCT03189810.

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.

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).

Do Determinants of Smoking Cessation and Relapse Differ between Men and Women? Data from a French National Study

Introduction: There is limited understanding of different predictors of smoking cessation success (SCS) among women and men, despite well-documented differences in smoking behavior.Methods: Using data from DePICT (Description des Perceptions, Images, et Comportements liés au Tabagisme), a national survey of French adults which recruited 2377 regular and former smokers we investigated whether major determinants of SCS differed by sex. Factors associated with unsuccessful vs. No successful quit attempt; vs. SCS were studied using multivariate multinomial logistic regression analyses stratified by sex.Results: Women and men share some determinants of SCS including no cannabis use, living in a nonsmoker household and importance giving to being a nonsmoker. However, no e-cigarette use, low-to-moderate alcohol consumption, early smoking initiation, and higher education were associated with SCS only among women. No use of nicotine replacement, having family members who smoke, family opinion on smoking and current employment, were associated with SCS only among men. Neutral or negative friends' opinion on smoking or living with a smoker were associated with unsuccessful smoking attempts among men.Conclusions: Our results show differences between determinants of SCS according to sex, which highlights the importance of developing tailored interventions that account for sex/gender differences in smoking cessation.

Effects of smoking on sleep architecture and ventilatory parameters including apneas: Results of the Tab-OSA study

Background

The interaction between smoking and sleep seems appears to be bidirectional, but few studies evaluated the impact of smoking and its cessation on objective sleep parameters. In this context, this new study aimed to assess the impact of smoking and its cessation on sleep architecture and on ventilatory sleep parameters, particularly the presence of sleep apnea syndrome (apnea-hypopnea index (AHI)≥15). Methods: Patients hospitalized for polysomnographic sleep exploration were compared according to their smoking status: active smokers (AS), former smokers (FS), non-smokers (NoNi). Psychiatric and non-psychiatric co-morbidities and treatment or substance use were taken into account in the analyses.

Results

A total of 170 participants were included (N = 37 FS, 39 AS, 86 NoNi). A significant decrease in the mean nocturnal O2 saturation was observed for FS and AS compared to NoNi. No differences were found regarding AHI. Regarding sleep architecture, we observed a significant decrease in the slow wave sleep duration for AS compared to NoNi, and interestingly not between FS and NoNi.

Conclusion

This study suggests that current smokers suffer from alterations in both sleep architecture and ventilatory parameters, the later appears to persist even after smoking cessation.

Examining indirect effects of advertising exposure on young adults' cannabis and nicotine vaping

OBJECTIVE

To examine longitudinal associations between exposure to two types of advertisements (medical/recreational cannabis and e-cigarette retailers [vape shops]) and young adults' cannabis and nicotine vaping behavior. Positive and negative expectancies for cannabis and vaping nicotine were examined as mediators of these associations.

METHOD

Secondary analysis of observational data from a longitudinal cohort of young adults recruited from Southern California (Wave 13: N = 2,411, 56% female, Mage = 23.6). Participants completed web-based surveys annually, reporting on advertising exposure in 2018, expectancies in 2019, and cannabis and nicotine vaping in 2020. Two path models were specified: (a) of past-month cannabis vaping only, nicotine vaping only, and co-use (vs. no vaping) and (b) of single product vaping (vs. co-use). Path analyses modeled direct and indirect associations between variables.

RESULTS

Controlling for past-month cannabis and nicotine use and other covariates, there were no significant direct associations of advertising exposure with cannabis and/or nicotine vaping. However, the association between cannabis advertising exposure and vaping (cannabis only) was significantly mediated by positive cannabis expectancies (β = 0.02, SE = 0.01, p = .03). Among those who vaped cannabis and/or nicotine in the past month at Wave 13, expectancies did not significantly mediate associations between advertising exposure and single product use (vs. co-use).

CONCLUSIONS

Although exposure to cannabis advertisements may not be directly associated with young adults' cannabis vaping 2 years later, the effects of advertising exposure may be exerted indirectly by increasing positive beliefs about cannabis. Implications for public health policy are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Understanding college students' experiences using e-cigarettes and marijuana through qualitative interviews

OBJECTIVE

To investigate the contexts in which college students use e-cigarettes and marijuana, perceptions about the benefits and harms, and health effects of use.

PARTICIPANTS

College student e-cigarette and marijuana ever users (n = 20; 18-21 years old) from the Texas Adolescent Tobacco and Marketing Surveillance System (TATAMS).

METHODS

Participants completed a one-hour long online interview about their experiences using e-cigarettes and marijuana. Thematic content analysis in NVivo identified prominent themes.

RESULTS

Vaping nicotine and marijuana were preferred and perceived as normal, trendy and useful in circumventing smoke-free campus policies. Preference for nicotine versus marijuana fluctuates during the academic school year in response to campus restrictions and work and school-related activities. College students commonly experienced health effects (shortness of breath, wheezing) attributed to vaping, did not perceive their use as very harmful, and perceived their use as a college-related phase.

CONCLUSIONS

Findings have implications for college-based health education, resources, and smoke-free policies.

Cannabis use and the risk of primary open-angle glaucoma: a Mendelian randomization study

Several observational studies have investigated the association between cannabis use and intraocular pressure, but its association with primary open-angle glaucoma (POAG) remains unclear. In this study, we leveraged human genetic data to assess through Mendelian randomization (MR) whether cannabis use affects POAG. We used five single-nucleotide polymorphisms (SNPs) associated with lifetime cannabis use (P-value < 5 × 10-8) from a genome-wide association study (GWAS) (N = 184,765) by the International Cannabis Consortium, 23andMe, and UK Biobank and eleven SNPs associated with cannabis use disorder (P-value < 5 × 10-7) from a GWAS meta-analysis of (17,068 cases and 357,219 controls of European descent) from Psychiatric Genomics Consortium Substance Use Disorders working group, Lundbeck Foundation Initiative for Integrative Psychiatric Research, and deCode. We associated the selected five SNPs from the GWAS of lifetime cannabis use and the eleven SNPs from the GWAS of cannabis use disorder, with the largest to date GWAS meta-analysis of POAG (16,677 cases and 199,580 controls). MR analysis suggested no evidence for a causal association of lifetime cannabis use and cannabis use disorder with POAG (odds ratio (OR) of outcome per doubling of the odds of exposure (95% confidence interval): 1.04 (0.88; 1.23) for lifetime cannabis use and 0.97 (0.92; 1.03) for cannabis use disorder). Sensitivity analyses to address pleiotropy and weak instrument bias yielded similar estimates to the primary analysis. In conclusion, our results do not support a causal association between cannabis use and POAG.

Pain is associated with exclusive use and co-use of tobacco and cannabis: Findings from Wave 5 (2018-2019) of the Population Assessment of Tobacco and Health Study

INTRODUCTION

Rates of tobacco and cannabis use are disproportionately high among individuals with pain, and evidence suggests that pain may engender greater likelihood of substance co-use, yielding additive risk. This study examined national associations of pain with past-month tobacco use, cannabis use, and co-use of tobacco and cannabis.

METHODS

Data came from a nationally representative US sample of adults in Wave 5 (2018-2019) of the Population Assessment of Tobacco and Health study (N = 32,014). The sample included civilian, non-institutionalized people who use tobacco and people who do not use tobacco. Past-week pain intensity (0-10) was dichotomized (0-4 no/low pain; 5-10 moderate/severe pain). Multinomial models adjusted for demographics examined substance use category membership (no tobacco or cannabis use, exclusive cannabis use, exclusive tobacco use, co-use) as a function of pain status.

RESULTS

Moderate/severe pain was associated with increased relative risk of exclusive tobacco use (RRR [CI] 2.26 [2.05, 2.49], p <.001), exclusive cannabis use (1.49 [1.22, 1.82], p <.001), and co-use of tobacco and cannabis (2.79 [2.51, 3.10], p <.001), in comparison to no tobacco or cannabis use. Additionally, moderate/severe pain was associated with increased risk of co-use compared to exclusive tobacco use (1.23 [1.11, 1.37], p <.001) and exclusive cannabis use (1.88 [1.54, 2.29], p <.001).

DISCUSSION

Findings suggest that not only is pain independently associated with greater risk of exclusively using tobacco or cannabis, but pain is also associated with heightened risk of co-using both products. Future work should examine the dynamic and potentially bidirectional relationships between pain and use of cannabis and tobacco.

Tobacco use in first-episode psychosis, a multinational EU-GEI study

BACKGROUND

Tobacco is a highly prevalent substance of abuse in patients with psychosis. Previous studies have reported an association between tobacco use and schizophrenia. The aim of this study was to analyze the relationship between tobacco use and first-episode psychosis (FEP), age at onset of psychosis, and specific diagnosis of psychosis.

METHODS

The sample consisted of 1105 FEP patients and 1355 controls from the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We assessed substance use with the Tobacco and Alcohol Questionnaire and performed a series of regression analyses using case-control status, age of onset of psychosis, and diagnosis as outcomes and tobacco use and frequency of tobacco use as predictors. Analyses were adjusted for sociodemographic characteristics, alcohol, and cannabis use.

RESULTS

After controlling for cannabis use, FEP patients were 2.6 times more likely to use tobacco [p ⩽ 0.001; adjusted odds ratio (AOR) 2.6; 95% confidence interval (CI) [2.1-3.2]] and 1.7 times more likely to smoke 20 or more cigarettes a day (p = 0.003; AOR 1.7; 95% CI [1.2-2.4]) than controls. Tobacco use was associated with an earlier age at psychosis onset (β = -2.3; p ⩽ 0.001; 95% CI [-3.7 to -0.9]) and was 1.3 times more frequent in FEP patients with a diagnosis of schizophrenia than in other diagnoses of psychosis (AOR 1.3; 95% CI [1.0-1.8]); however, these results were no longer significant after controlling for cannabis use.

CONCLUSIONS

Tobacco and heavy-tobacco use are associated with increased odds of FEP. These findings further support the relevance of tobacco prevention in young populations.

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.

Experimenter administered Δ9-THC decreases nicotine self-administration in a rat model

BACKGROUND

The co-use of nicotine and cannabis has been steadily rising in the United States. Rodent studies suggest that delta-9-tetrahydrocannabinol (THC) could increase addictive qualities of nicotine, but whether repeated THC exposure alters self-administration of nicotine has not been tested. We hypothesized that THC would increase the reinforcing effects of nicotine and alter nicotine intake.

METHODS

Adult male and female Sprague-Dawley rats were treated with THC (0, 3, 30 mg/kg) daily for 14 days prior to and during training for intravenous self-administration of nicotine. Rats were allowed to self-administer nicotine for several weeks, then tested for sensitivity to nicotine dose through multiple determinations of a nicotine dose-effect curve with or without THC pretreatment. A separate set of rats were trained on fixed ratio responding for sucrose and assessed for THC effects on behavior.

RESULTS

Post-session THC decreased nicotine self-administration in male and female rats throughout acquisition and maintenance and increased the latency to stable rates of nicotine intake during acquisition. Post-session THC shifted nicotine dose-effect curves downward, and pre-session THC suppressed responding at higher nicotine doses. Unlike nicotine, responding for sucrose was not affected by post-session THC. Pre-session THC decreased responding for sucrose, particularly for THC-naïve rats.

CONCLUSIONS

Repeated post-session THC decreased nicotine-taking behaviors but did not alter sucrose responding. Thus, post-session THC may alter sensitivity to nicotine. Pre-session THC treatment decreased lever pressing in both sucrose and nicotine studies, indicating this effect was nonspecific. These studies show that THC modulates patterns of nicotine intake in rat models.

Multiple Substance Use Patterns and Its Relationship with Imprisonment in a High-Risk Group of Iranian Adults

BACKGROUND

Substance use is recognized as an important factor associated with many diseases and premature deaths and the main risk factor for disability worldwide. This study aims to identify subgroups of substance use in adults and detect the effect of imprisonment on the membership of participants in latent classes of substance use. Study Design: A cross-sectional study.

METHODS

This study was performed on 930 adult people who were referred to behavioral health counseling centers in Tehran province. All participants completed some checklists and questionnaires. Data analysis was performed using chi-square, Fisher's exact test, and latent class analysis (LCA).

RESULTS

Four latent classes were identified, including non-users (58%), cigarette smokers (11.6%), users of low stigma substances (27.4%), and drug users (3.1%). After adjusting for other studied variables, having a history of imprisonment increased the odds of membership in the cigarette smoker class (Odds ratio [OR]=5.82, 95%, confidence interval [CI]: 3.19-10.63) and drug user class (OR=53.59, 95% CI: 18.00- 159.52) compared to non-user class. Among all participants, 84 (9.0%) had a history of imprisonment.

CONCLUSION

Results from the present study indicate that 30.5% of the participants fell under the user of the low-stigma substance or drug user group. Focusing on increasing prisoner's knowledge of the dangers of using different substances and considering various programs for prisoners' leisure time may help reduce substance use prevalence.

Cannabis and tobacco use among adolescents aged 12-17 years from 16 low- and middle-income countries

Background

We aimed to examine the association between cannabis use and tobacco use in 12-17-year-old adolescents residing in low- and middle-income countries (LMICs).

Methods

We used data from the Global School-based Student Health Survey collected between 2012 and 2022. We selected 16 LMICs based on pre-defined inclusion criteria and compared the prevalence of cannabis use for female and for male adolescents for each country. We estimated age- and sex-standardised distributions of tobacco use, school truancy, suicide attempt, sex with multiple partners, physical fighting, perceived school kindness, and parental monitoring were estimated. We used multivariable logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) measuring associations between cannabis use and other variables. We generated pooled estimates through random effects meta-analyses.

Results

The overall pooled prevalence of cannabis use was 4.3% (95% CI = 3.2-5.9), with significant between-country heterogeneities (I² = 91.4%; P = 0.000). Cannabis use was more prevalent in males than in females in each country. Tobacco use was strongly associated with cannabis use in all 16 LMICs. Tobacco users had approximately 11 to 14 times greater odds of cannabis use than non-tobacco users. Sex with multiple partners, suicide attempts, and school truancy had a robust association with cannabis use in over half of LMICs.

Conclusions

There is a need for comprehensive preventive measures targeting multiple risk behaviours associated with cannabis use for adolescents in LMICs.

Differentiating people who use cannabis heavily through latent class analysis

BACKGROUND

People who use cannabis daily or near-daily vary considerably in their daily dosage and use frequency, impacting both experienced effects and adverse consequences. This study identified heavy cannabis user groups according to consumption patterns and factors associated with class membership.

METHODS

We conducted a cross-sectional study of 380 Spanish residents (61.8% male; average age = 30.3 years) who had used cannabis ≥ 3 days/week throughout the past year. Participants were recruited through chain referral and cannabis social clubs. We applied latent class analysis (LCA) to cluster participants according to use intensity. LCA indicators included frequency of weekly cannabis use, joints smoked each day, cannabis dosage, and if cannabis was consumed throughout the day or only at specific times. Associations between class membership and socio-demographics, use patterns, motives, supply sources, adverse outcomes, and use of other substances were measured using ANOVA and chi-squared tests. Multinomial regression identified the factors associated with latent class membership.

RESULTS

Three latent classes (moderately heavy: 21.8%, heavy: 68.2%, very heavy: 10%) had average weekly cannabis intakes of 2.4, 5.5, and 18.3 g, respectively. Very heavy users were older ([Formula: see text]=17.77, p < 0.01), less educated [Formula: see text]=36.80, p < 0.001), and had used cannabis for longer (F = 4.62, p = 0.01). CAST scores (F = 26.51, p < 0.001) increased across the classes. The prevalence of past-month alcohol use was lower among the heaviest users ([Formula: see text]=5.95, p = 0.05). Cannabis was usually obtained from a club by very heavy users ([Formula: see text]=20.95, p < 0.001).

CONCLUSIONS

People who use cannabis heavily present three groups according to frequency and quantity of cannabis consumption. Use intensity is associated with increased cannabis-related problems. Differences among heavy users must be considered in harm reduction interventions in cannabis clubs and indicated prevention.

Blunt and non-blunt cannabis use associated with cigarette, e-cigarette, and cigar initiation: Findings from the population assessment of tobacco and health (PATH) study

BACKGROUND

Smoking cannabis using a tobacco-derived cigar shell or wrap, called blunt smoking, exposes individuals to non-trivial amounts of nicotine. The extent smoking blunts impact the risk of initiating other tobacco products is not well understood. We investigated if past-year blunt smoking is related to the risk of initiating cigarettes, e-cigarettes, and cigars.

METHODS

We obtained data on a nationally representative, non-institutionalized, civilian cohort of US residents aged 12 years and older who had never used cigarettes, e-cigarettes, or any cigar at baseline and surveyed annually for three years from the Population Assessment of Tobacco and Health Study. We estimated the proportional hazard (odds) of initiating these tobacco products associated with past-year blunt smoking, non-blunt cannabis use, or neither using discrete-time survival analyses.

RESULTS

Smoking blunts increased the risk of starting cigarettes (OR = 4.5), e-cigarettes (OR = 3.7), and cigars (OR = 6.7) compared to using neither blunts nor cannabis. Non-blunt cannabis use also increased the risk of starting cigarettes (OR = 4.0) but moderately for e-cigarettes (OR = 2.8) and any cigar (OR = 2.2). Blunt use was strongly related to starting combustible tobacco (cigarettes or cigars; OR = 9.0) and any three tobacco products (OR = 10.9). Exploratory findings showed that cigarillos drove cigar results and effect modification by age, race/ethnicity, and sex.

CONCLUSIONS

People who smoke blunts risk starting cigarettes, e-cigarettes, and cigars more than those who abstain from cannabis. Blunts may contribute to tobacco initiation above cannabis alone.

Prevalence of depressive symptoms and cannabis use among adult cigarette smokers in Canada: cross-sectional findings from the 2020 International Tobacco Control Policy Evaluation Project Canada Smoking and Vaping Survey

BACKGROUND

Tobacco smoking and cannabis use are independently associated with depression, and evidence suggests that people who use both tobacco and cannabis (co-consumers) are more likely to report mental health problems, greater nicotine dependence and alcohol misuse than those who use either product exclusively. We examined prevalence of cannabis use and depressive symptoms among Canadian adults who smoke cigarettes and tested whether co-consumers of cannabis and tobacco were more likely to report depressive symptoms than cigarette-only smokers; we also tested whether cigarette-only smokers and co-consumers differed on cigarette dependence measures, motivation to quit smoking and risky alcohol use by the presence or absence of depressive symptoms.

METHODS

We analyzed cross-sectional data from adult (age ≥ 18 yr) current (≥ monthly) cigarette smokers from the Canadian arm of the 2020 International Tobacco Control Policy Evaluation Project Four Country Smoking and Vaping Survey. Canadian respondents were recruited from Leger's online probability panel across all 10 provinces. We estimated weighted percentages for depressive symptoms and cannabis use among all respondents and tested whether co-consumers (≥ monthly use of cannabis and cigarettes) were more likely to report depressive symptoms than cigarette-only smokers. Weighted multivariable regression models were used to identify differences between co-consumers and cigarette-only smokers with and without depressive symptoms.

RESULTS

A total of 2843 current smokers were included in the study. The prevalence of past-year, past-30-day and daily cannabis use was 44.0%, 33.2% and 16.1%, respectively (30.4% reported using cannabis at least monthly). Among all respondents, 30.0% screened positive for depressive symptoms, with co-consumers being more likely to report depressive symptoms (36.5%) than those who did not report current cannabis use (27.4%, p < 0.001). Depressive symptoms were associated with planning to quit smoking (p = 0.01), having made multiple attempts to quit smoking (p < 0.001), the perception of being very addicted to cigarettes (p < 0.001) and strong urges to smoke (p = 0.001), whereas cannabis use was not (all p ≥ 0.05). Cannabis use was associated with high-risk alcohol consumption (p < 0.001), whereas depressive symptoms were not (p = 0.1).

INTERPRETATION

Co-consumers were more likely to report depressive symptoms and high-risk alcohol consumption; however, only depression, and not cannabis use, was associated with greater motivation to quit smoking and greater perceived dependence on cigarettes. A deeper understanding of how cannabis, alcohol use and depression interact among people who smoke cigarettes is needed, as well as how these factors affect cessation activity over time.