Is marijuana use becoming a 'gateway' to nicotine dependence?

Using mixed methods to establish tobacco treatment acceptability from the perspective of clients and clinicians of antenatal substance use services

Background

Up to 95% of pregnant women with alcohol and other drug (AOD) problems also smoke tobacco. Challenging psychosocial circumstances and a lack of targeted tobacco interventions contribute to low rates of prenatal abstinence and more effective treatment strategies are required. This study explores smoking in pregnant clients of AOD treatment services from a consumer and healthcare provider perspective to examine characteristics of behaviour change and the acceptability of evidence-based tobacco treatment strategies. Outcomes will support the design and implementation of a comprehensive tobacco intervention.

Methods

A mixed methods triangulated design was used. Thirteen women who smoked and attended antenatal AOD services in New South Wales, Australia, were interviewed and 28 clinicians from the same services were surveyed. Domains including experiences of tobacco smoking in pregnancy, motivators and barriers to cessation and evidence-based strategies to assist cessation during pregnancy were explored. Interviews were analysed using Iterative Categorization, with interpretation guided by Qualitative Description. Online surveys were analysed descriptively. A convergent-parallel mixed methods analysis was performed.

Results

Women and clinicians agreed that improving baby’s health outcomes was the primary motivation to stop smoking. Negative experiences with nicotine replacement therapy (NRT), financial constraints and maternal contraindications restricted its uptake and effectiveness during pregnancy. Both groups agreed that other AOD use, stopping multiple substances concurrently, difficulty coping with stress and the influence of partners who smoke had the biggest impacts on cessation efforts. Clinicians favoured harm-reduction rather than abstinence-based tobacco interventions and women appeared satisfied with reduction efforts. Both views may influence the attainment of prenatal abstinence-based goals. Although previous evidence suggested the contrary, clinicians were willing to encourage simultaneous cessation of tobacco and other substances. Non-judgmental treatment approaches that provide extra support, education and motivation were important for women. Women and clinicians supported use of NRT despite concerns. Financial incentives, counselling, partner support and offering tobacco treatment with antenatal AOD care were considered acceptable treatment options.

Conclusions

NRT, incentives, counselling and partner support could be utilized in a tobacco intervention for pregnant women with substance use concerns. Non-judgmental education, motivation, and provision of NRT including instruction for correct use are important considerations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13722-022-00337-y.

Co-use and Mixing Tobacco With Cannabis Among Ontario Adults

INTRODUCTION

The legalization of nonmedical cannabis in 2018 may have important implications for tobacco use in Canada. There is a risk of renormalizing tobacco use with co-use of tobacco and cannabis introducing nontobacco users to tobacco. Co-use is the use of both substances by the same individual at the same time or on different occasions, as well as mixed together. This study assessed the prevalence of co-use and mixing of tobacco and cannabis among Ontario adults and the characteristics of the users.

AIMS AND METHODS

Data from the 1996 to 2017 cycles of the Centre for Addiction and Mental Health Monitor (n = 4481) were used to examine trends in prevalence and the proportion of Ontario adults co-using and mixing tobacco and cannabis. Logistic regression was used to study associations between user characteristics and co-use and mixing.

RESULTS

Co-use of cigarettes and cannabis among cannabis users declined from 59.8% in 1996 to 41.7% in 2017. Past-year e-cigarette use was the only predictor of co-use. From 2015 to 2017, 31.1% (95% confidence interval 27.0, 35.9) of Ontario adults who used cannabis reported mixing it with tobacco in the past year. Being white, past-year e-cigarette use, having moderate or high nicotine dependence, and having moderate or high risk for cannabis problems were significant predictors of mixing among cannabis users.

CONCLUSION

Given the well-established negative health effects associated with tobacco use, alongside a growing evidence base for negative health effects of cannabis smoking, co-use and mixing could pose a considerable public health concern in the context of legalization.

IMPLICATIONS

Considerable effort has been expended to reduce tobacco smoking. However, current efforts to reduce tobacco smoking may be diminished since this study found the prevalence of mixing tobacco and cannabis among cannabis users in Ontario to be higher than expected. Mixing tobacco and cannabis may introduce nontobacco smokers to tobacco, exposing them to health risks associated with both cannabis and tobacco smoke. Therefore, there is a need to monitor changes in tobacco use and understanding implications for tobacco control and cessation programs within the changing environment of cannabis legalization in Canada and other jurisdictions.

Marijuana Use and Sexual Risk Behavior Among Young Black Men Who Have Sex with Men in California

Young black men who have sex with men (YBMSM) are disproportionately affected by HIV and continue to experience higher rates of new HIV infections when compared to other population groups. As part of the Peer Promotion of Wellness and Enhanced Linkage to Resources Project, we examined problem marijuana use and the overall sexual risk profile of 250 YBMSM. Eighty percent reported prior use of marijuana in their lifetime (n = 200). Among those, problem marijuana use was correlated with problem use of alcohol (r = 0.51, p < 0.001) and other drugs (r = 0.29, p < 0.001); lower household income (r = - .22, p < .01); homelessness (r = 0.15, p < 0.05); incarceration (r = 0.16, p < 0.05); exchanging sex for money, drugs, or shelter (r = 0.18, p < 0.05); having sex with someone known or suspected of having HIV and/or an STI (r = 0.20, p < 0.01); having sex with someone known or suspected of being an injector (r = 0.24, p < 0.01); and having unprotected sex while under the influence of alcohol or drugs (r = 0.32, p < 0.001). The complex relationship between marijuana and sexual risk behavior was examined while accounting for the possible moderating effects of alcohol or other drugs. Problem marijuana, alcohol, and other drug use each made unique contributions to predicting risky sex behavior. A significant marijuana and other drug interaction was found to predict sexual risk behaviors. Future efforts should include holistic intervention approaches for YBMSM that consider factors facilitating high-risk sexual behaviors.

Changes in the Order of Cigarette and Marijuana Initiation and Associations with Cigarette Use, Nicotine Vaping, and Marijuana Use: U.S. 12th Grade Students, 2000-2019

This study (a) examined changes in marijuana and cigarette initiation sequencing and (b) considered implications of such changes for prevention efforts by examining associations between initiation sequencing and current adolescent substance use. Analyses used 2000-2019 cross-sectional data from the national Monitoring the Future (MTF) study (78,252 U.S. 12th grade students). Models examined trends in six distinct patterns of initiation order, and multivariable associations between order of initiation and 30-day cigarette and marijuana use prevalence, cigarette and marijuana use frequency among users, and nicotine and marijuana vaping prevalence. While the percentage of students initiating neither cigarettes nor marijuana increased, increases also were observed in marijuana-only initiation (the fastest-growing pattern) and initiation of marijuana before cigarettes; these increases were accompanied by a significant decrease in cigarette-only initiation. Cigarette use prevalence and frequency were highest among students initiating cigarettes before marijuana; marijuana use prevalence and frequency were highest among students initiating marijuana before cigarettes. Cigarette and marijuana prevalence, as well as marijuana frequency, were lowest among students initiating only a single substance. Nicotine vaping was less prevalent among students initiating a single substance versus both substances, but no significant differences were observed in nicotine vaping prevalence between those initiating only cigarettes versus only marijuana. Implications of these findings for prevention efforts are discussed in the frameworks of both the common liability model and route of administration model.

Interventions for pregnant women who use tobacco and other substances: a systematic review protocol

INTRODUCTION

The prevalence of tobacco smoking in pregnancy remains elevated in some disadvantaged populations of women. One group is those who use alcohol and/or other psychoactive substances during pregnancy, with tobacco use prevalence estimates ranging from 71% to 95%. Although effective evidence-based cessation treatments exist, few women with co-occurring substance use problems successfully stop smoking during pregnancy. There is limited information about treatments that specifically target this group and a summary of the available research is required to assist and enhance the development of innovative cessation interventions. This article describes a protocol for a comprehensive review of studies that have trialled behavioural and/or pharmacological tobacco cessation interventions in populations of pregnant women who are nicotine dependent and use alcohol and/or other psychoactive substances.

METHODS AND ANALYSIS

The review will undertake literature searches in MEDLINE, PsycINFO, CINAHL, EMBASE and ProQuest databases, as well as the grey literature. Studies of any design methodology will be included if they describe changes to tobacco smoking behaviours in quantitative terms. No restriction on year of publication or published language will apply. Participants include pregnant women of any age, who smoke tobacco, who are seeking or having treatment, or in post-treatment recovery for the use of psychoactive substances. Interventions are any psychological, behavioural or pharmacological treatments used to treat tobacco use. Outcome measures are any that quantitatively report abstinence or reductions in participant tobacco consumption. Key details and tobacco-related outcomes from included studies will be extracted and tabulated before being narratively synthesised. The systematic review protocol has been developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines.

ETHICS AND DISSEMINATION

Ethics approval is not required. Findings will be disseminated via peer-reviewed literature, conference presentations, media and social media.

PROSPERO REGISTRATION NUMBER

CRD42018108777.

Alcohol, tobacco, and marijuana consumption is associated with increased odds of same-day substance co- and tri-use

BACKGROUND

Little is known about event-level patterns of marijuana co- or tri-use with alcohol and tobacco. Thus, the study goal was to examine patterns of same-day alcohol, cigarette, and marijuana co- and tri-use at the individual level in non-treatment-seeking alcohol users.

METHODS

Participants (N = 551) completed an in-person interview for alcohol, cigarette, and marijuana use over the previous 30 days, and the event-level substance use patterns of n = 179 participants who reported using each of these substances at least once per month were analyzed.

RESULTS

The use of alcohol, marijuana, or cigarettes independently increased the probability of subsequent, simultaneous co-use of one of the two remaining substances. The co-use of alcohol with cigarettes and marijuana with cigarettes produced generally additive effects on the odds of same day tri-use of marijuana and alcohol, respectively. Conversely, the co-use of alcohol and marijuana produced sub-additive effects on likelihood of cigarette use. Sex moderated several of the observed patterns of co- and tri-use: the relationship between alcohol or cigarette use predicting marijuana co-use was stronger in men, whereas the observed additive relationships between drug co-use leading to tri-use was stronger in women.

CONCLUSIONS

The presented results may aid in the understanding of how simultaneous co-use of marijuana with alcohol and/or tobacco relates to the etiology, maintenance, and treatment of comorbid and trimorbid substance use disorder. Replication and extension of the results in treatment seeking populations using more fine-grained analysis approaches, e.g. ecological momentary assessment, is needed.

Identifying behavioural characteristics of tobacco product and e-cigarette use clusters: A repeat cross-sectional analysis

BACKGROUND

Youth may use a variety of tobacco products and e-cigarettes. However, there is a lack of evidence for the combinations of tobacco products and e-cigarettes commonly used by youth in Canada and whether youth from different usage classes share similar characteristics.

METHODS

A cohort of 9th grade students from Ontario, Canada was identified at baseline (2013-14) of the COMPASS study (n = 4651). Classes of youth that currently use similar combinations of tobacco products and e-cigarettes were identified at baseline, one (FY1) and two years later (FY2) using latent class analysis. Multinomial logistic regression models identified demographic and behavioural characteristics (e.g., environmental influences, substance use behaviours, etc.) of youth in current tobacco and e-cigarette use classes relative to youth in non-current use classes.

RESULTS

At baseline, a three-class model was identified as best, while a four-class model was identified at FY1 and FY2. A non-current use group and an all-product use group were identified every year. Students that reported having friends that smoked cigarettes, binge drinking, and using marijuana were more likely to be classified into a current use class.

CONCLUSIONS

Tobacco cigarettes were more likely to be used with other products than on their own. An all-product use group was identified across all three survey waves and the prevalence of this group increased over time. Given that many youth in this study used more than one tobacco product or e-cigarette and commonly reported binge drinking and using marijuana, prevention and cessation activities should address the use of multiple products.

Does Marijuana Use at Ages 16-18 Predict Initiation of Daily Cigarette Smoking in Late Adolescence and Early Adulthood? A Propensity Score Analysis of Add Health Data

Given the declining trend in adolescent cigarette smoking and increase in general access to marijuana, it is important to examine whether marijuana use in adolescence is a risk factor for subsequent cigarette smoking in late adolescence and early adulthood. Preliminary evidence from a very small number of studies suggests that marijuana use during adolescence is associated with later smoking; however, to control confounding, previously published studies used regression adjustment, which is susceptible to extrapolation when the confounder distributions differ between adolescent marijuana users and non-users. The current study uses propensity score weighting, a causal inference method not previously used in this area of research, to weight participants based on their estimated probability of exposure given confounders (the propensity score) to balance observed confounders between marijuana users and non-users. The sample consists of participants of Add Health (a nationally representative dataset of youth followed into adulthood) who were 16-18, with no history of daily cigarette smoking at baseline (n = 2928 for female and 2731 for male sub-samples). We assessed the effect of adolescent marijuana use (exposure, ascertained at wave 1) on any daily cigarette smoking during the subsequent 13 years (outcome, ascertained at wave 4). Analyses suggest that for females (but not males) who used marijuana in adolescence, marijuana use increased the risk for subsequent daily smoking: OR = 1.71, 95% CI = (1.13, 2.59). We recommend that adolescent marijuana use be viewed as a possible risk factor for subsequent initiation of daily cigarette smoking in women.

The interdependence of cigarette, alcohol, and marijuana use in the context of school-based social networks

The concurrent or sequential usage of multiple substances during adolescence is a serious public health problem. Given the importance of understanding interdependence in substance use during adolescence, the purpose of this study is to examine the co-evolution of cigarette smoking, alcohol, and marijuana use within the ever-changing landscape of adolescent friendship networks, which are a primary socialization context for adolescent substance use. Utilizing Stochastic Actor-Based models, we examine how multiple simultaneous social processes co-evolve with adolescent smoking, drinking, and marijuana use within adolescent friendship networks using two school samples from early waves of the National Longitudinal Study of Adolescent to Adult Health (Add Health). We also estimate two separate models examining the effects from using one substance to the initiation and cessation of other substances for each sample. Based on the initial model results, we simulate the model forward in time by turning off one key effect in the estimated model at a time, and observe how the distribution of use of each substance changes. We find evidence of a unilateral causal relationship from marijuana use to subsequent smoking and drinking behaviors, resulting in the initiation of drinking behavior. Marijuana use is also associated with smoking initiation in a school with a low substance use level, and smoking cessation in a school with a high substance use level. In addition, in a simulation model excluding the effect from marijuana use to smoking and drinking behavior, the number of smokers and drinkers decreases precipitously. Overall, our findings indicate some evidence of sequential drug use, as marijuana use increased subsequent smoking and drinking behavior and indicate that an adolescent's level of marijuana use affects the initiation and continuation of smoking and drinking.

Correlates and trends in youth co-use of marijuana and tobacco in the United States, 2005-2014

BACKGROUND

Past-month marijuana and tobacco use (co-use) are increasing among U.S. adults, but little is known about the prevalence of co-use among U.S. youth. This study uses nationally representative data to assess the prevalence, correlates, and trends in co-use of marijuana and tobacco, tobacco-only use, and marijuana-only use among U.S. youth.

METHODS

Data came from 176,245 youth ages 12-17 who responded to the National Survey on Drug Use and Health - a nationally representative, household interview survey - between 2005 and 2014. Prevalence, demographics and substance use characteristics from 2013 to 14 were assessed across three groups: past-month users of marijuana and tobacco (co-users), past-month tobacco-only users, and past-month marijuana-only users. Multinomial logistic regression was used to assess demographic correlates of each group. Linear and quadratic trends were assessed from 2005 to 2014 using logistic regression with orthogonal polynomials.

RESULTS

In 2013-14, 5.4% of youth reported past-month co-use of tobacco and marijuana, 2.2% reported marijuana-only use, and 3.9% reported tobacco-only use. Co-use was associated with higher prevalence of past year marijuana dependence (vs. marijuana-only users), and higher past-month risky alcohol and other illicit drug use (vs. both tobacco and marijuana-only use groups). Co-use did not increase significantly between 2005 and 2014; tobacco-only use declined, and marijuana-only use increased.

CONCLUSIONS

Co-use of marijuana and tobacco is more prevalent than tobacco-only or marijuana-only use in U.S. youth. Given changing tobacco and marijuana policies, ongoing surveillance and studies that seek to increase our understanding of co-use behaviors in youth are critical.

The association between cannabis use and motivation and intentions to quit tobacco within a sample of Australian socioeconomically disadvantaged smokers

This study aimed to (i) describe concurrent and simultaneous tobacco and cannabis use and (ii) investigate the association between cannabis use and motivation and intentions to quit tobacco in a sample of socioeconomically disadvantaged smokers. A cross-sectional survey was conducted in 2013 and 2014 with current tobacco smokers receiving aid from two community service organizations in New South Wales, Australia. At least weekly cannabis use for the month prior to survey, motivation to quit tobacco and intentions to quit tobacco were measured in 369 participants (77% consent rate). Regressions were carried out to investigate associations between weekly cannabis use and motivation and intentions to quit tobacco.Concurrent tobacco and cannabis use was reported by 19% (n = 71) of the sample and of these users, 100% reported simultaneous use. Although regular cannabis use was significantly associated with lower motivation to quit tobacco, it was not significantly associated with intentions to quit tobacco in the next 30 days. Concurrent cannabis use is common in disadvantaged smokers and may play a role in decreased motivation to quit tobacco; however, it does not appear to be associated with intentions to quit in a sample of disadvantaged smokers.

Medical marijuana legalization and cigarette and marijuana co-use in adolescents and adults

BACKGROUND

Medical marijuana legalization is associated with a higher prevalence of marijuana use which may affect cigarette use and nicotine dependence in co-users. In the present study, we examined relationships between statewide legalization of medical marijuana and prevalence of cigarette and marijuana co-use and nicotine dependence in co-using adolescents and adults.

METHODS

Data were analyzed from the 2013 National Survey on Drug Use and Health. We compared cigarette and marijuana co-use in the past 30days across age categories (12-64 years) by statewide medical marijuana legalization. Logistic regression models were used to estimate the odds of having nicotine dependence among current cigarette smokers who also reported past 30-day marijuana use and "ever but not current" marijuana use (vs. "never" use) adjusting for covariates including statewide legalization of medical marijuana.

RESULTS

Overall, 5.1% of the sample reported past 30-day cigarette and marijuana co-use and a higher proportion of co-users resided in states where medical marijuana was legal compared to illegal (5.8% vs. 4.8%; p=0.0011). Co-use was associated with greater odds of having nicotine dependence compared to cigarette-only use across age categories. Odds were highest and up to 3-times higher in adolescents aged 12-17 years (OR=3.54; 95%CI: 1.81-6.92) and adults aged 50-64 years (OR=3.08; CI: 1.45-6.55).

CONCLUSION

Marijuana policy could inadvertently affect cigarette and marijuana co-use and pose challenges to tobacco cessation.

Racial differences and the role of neighborhood in the sequencing of marijuana and tobacco initiation among urban youth

BACKGROUND

With patterns of initiation of tobacco and marijuana changing, there is increasing evidence that marijuana use may serve as an antecedent to tobacco use among adolescents. However, studies have not fully characterized the prevalence of these patterns among vulnerable youth and have rarely examined the factors that predict the sequencing of onset of tobacco and marijuana use.

METHODS

Utilizing longitudinal data from a sample of urban youth followed from age 6 to age 18, the authors identify the sequencing of initiation of tobacco and marijuana and test whether race and 5 neighborhood factors (i.e., perceived disorder, drug activity, drug access, exposure to violence, and exposure to violent victimization) predict onset sequencing.

RESULTS

Various sequencing patterns were observed, with 12.4% of the sample initiating marijuana use before tobacco use was initiated. In adjusted logistic regression models, black youth were 2.66 times as likely as whites to initiate marijuana before tobacco compared with initiating tobacco before marijuana (P = .032). Youth with greater exposure to violent victimization were 3.89 times as likely to initiate marijuana first than initiate tobacco first (P = .002). Other neighborhood factors were not statistically significantly associated with sequencing.

CONCLUSIONS

Black youth and youth with greater exposure to victimization had an increased risk of initiating marijuana before tobacco, which suggests that this pattern may be rooted in specific risk factors. Substance use prevention efforts should consider taking into account that marijuana use may put certain youth at risk of initiating tobacco. Future research needs to monitor sequencing, as well as risk factors for and consequences of the various patterns, particularly since marijuana use and the mixing of tobacco and marijuana use are gaining acceptability in general populations.

Medical Marijuana Legalization and Co-use in Adult Cigarette Smokers

OBJECTIVES

We examined effects of long-term medical marijuana legalization on cigarette co-use in a sample of adults.

METHODS

We conducted secondary analysis using data from the 2014 US Tobacco Attitudes and Beliefs Survey, which consisted of cigarette smokers, aged ≥ 45 years (N = 506). Participants were categorized by their state residence, where medical marijuana was (1) illegal, (2) legalized < 10 years, and (3) legalized ≥ 10 years. The Web-based survey assessed participants' marijuana use, beliefs and attitudes on marijuana, and nicotine dependence using Fagerstrom Tolerance for Nicotine Dependence (FTND) and Hooked on Nicotine Checklist (HONC) scores.

RESULTS

In cigarette smokers aged ≥ 45 years, long-term legalization of medical marijuana was associated with stable positive increases in marijuana use prevalence (ever in a lifetime) (p = .005) and frequency (number of days in past 30 days) (unadjusted p = .005; adjusted p = .08). Those who reported marijuana co-use had greater FTND and HONC scores after adjusting for covariates (p = .05).

CONCLUSIONS

These preliminary findings warrant further examination of the potential impact of long-term legalization of medical marijuana on greater cigarette and marijuana co-use in adults and higher nicotine dependence among co-users at the population level.

Trajectories of Marijuana Use Beginning in Adolescence Predict Tobacco Dependence in Adulthood

BACKGROUND

Although the "stage theory" suggests that marijuana use occurs after the initiation of tobacco smoking, substantial evidence exists that they often occur concurrently, and that the use of marijuana may influence the use of tobacco.

METHODS

This study uses trajectory analysis to examine the relationship between marijuana use beginning in adolescence and adult tobacco dependence in a 5-wave longitudinal study (mean ages in each wave: 14, 19, 24, 29, and 32). The sample consisted of 816 participants (52% African Americans, 48% Puerto Ricans), of whom 60% were females. Logistic regression analyses were conducted to predict later tobacco dependence from earlier trajectories of marijuana use.

RESULTS

A higher Bayesian posterior probability (BPP) for the chronic marijuana use trajectory group (odds ratio [OR]=10.93, P<.001; adjusted OR [AOR]=10.40, P<.001), for the increasing marijuana use trajectory group (OR=6.94, P<.001; AOR=6.73, P<.001), and for the moderate marijuana use trajectory group (OR=3.13, P<.001; AOR=3.18, P<.001) was associated with an increased likelihood of being dependent on tobacco compared with the BPP of the no or low marijuana use trajectory group.

CONCLUSIONS

The results underscore the value of considering multiple patterns of marijuana use within a person-centered approach. Thus, it would be appropriate for marijuana cessation programs to incorporate the prevention, assessment, and cessation of tobacco use in their health promotion strategies.

Electronic cigarette effectiveness and abuse liability: predicting and regulating nicotine flux

Electronic cigarettes (ECIGs) comprise an aerosolized nicotine delivery product category that provides consumers with probably unprecedented control over extensive features and operating conditions, allowing a wide range of nicotine yields to be obtained. Depending on the combination of such ECIG variables as electrical power input, geometry, liquid composition, and puff behavior, ECIG users can extract in a few puffs far more or far less nicotine than with a conventional combustible cigarette. These features of ECIG design and use present challenges for public health policy, central among which is the question of how to regulate nicotine delivery. In this commentary, we propose a conceptual framework intended to provide a convenient approach for evaluating and regulating the nicotine emitted from ECIGs. This framework employs nicotine flux to account for the total dose and rate at which nicotine reaches the user, 2 key factors in drug abuse liability. The nicotine flux is the nicotine emitted per puff second (e.g., mg/s) by a given ECIG design under given use conditions, and it can be predicted accurately using physical principles. We speculate that if the flux is too low, users likely will abandon the device and maintain conventional tobacco product use. Also, we speculate that if the flux is too high, individuals may suffer toxic side effects and/or the device may have higher-than-necessary abuse liability. By considering ECIG design, operation conditions, liquid composition, and puff behavior variables in combination, we illustrate how ECIG specifications can be realistically mandated to result in a target flux range.

Concurrent tobacco and khat use is associated with blunted cardiovascular stress response and enhanced negative mood: a cross-sectional investigation

OBJECTIVES

Khat (Catha edulis), an amphetamine-like plant, is widely used in East Africa and the Arabian Peninsula and is becoming a growing problem in other parts of the world. The concurrent use of tobacco and khat is highly prevalent and represents a public health challenge. We examined for the first time associations of the concurrent use of tobacco and khat with psychophysiological responses to acute stress in two sites in Yemen.

METHODS

Participants (N = 308; 135 women) included three groups: users of khat and tobacco, users of khat alone, and a control group (nonsmokers/nonusers of khat). These individuals completed a laboratory session in which blood pressures (BP), heart rate, and mood measures were assessed during rest and in response to acute stress.

RESULTS

Concurrent use of khat and tobacco was associated with attenuated systolic BP, diastolic BP, and heart rate responses to laboratory stress (ps < 0.05) and with increased negative affect relative to the control group (ps < 0.05).

CONCLUSIONS

Results demonstrated blunted cardiovascular responses to stress and enhanced negative affect in concurrent khat and tobacco users. These findings extend previous studies with other substances and suggest that adverse effects of khat use may lie in its association with the use of tobacco.

Hostility and cigarette use: a comparison between smokers and nonsmokers in a matched sample of adolescents

INTRODUCTION

We examined the association between hostility-a personality trait reflective of negativity and cynicism toward others-and smoking in adolescents by measuring (a) several subcomponents of hostility, and (b) facial emotion processing ability, which has been previously linked to hostility.

METHODS

Participants (N = 241 aged 14-19) were 95 smokers and 95 demographically matched nonsmokers as well as 51 nonmatched smokers. All participants completed the Cook-Medley (C-M) hostility scale, which provides a general hostility score and 3 component scores (cynicism, hypersensitivity, and aggressive responding), and a facial emotion processing task. This task, designed to assess emotion recognition, requires quickly identifying the emotion of faces that gradually morph from neutral to high-intensity happy, angry, or fearful.

RESULTS

Independent sample t tests indicated that matched smokers scored significantly higher in cynicism and aggressive responding than nonsmokers. Among smokers, age of smoking onset was negatively correlated with general hostility and aggressive responding. All hostility scales were positively correlated with the intensity needed to recognize happy faces. Counterintuitively, smokers required a greater intensity to recognize angry faces than nonsmokers. No other relations between hostility/smoking status and facial emotion processing were observed.

CONCLUSIONS

Aspects of hostility, particularly aggressive responding, may be a risk factor for early onset smoking. Although hostile participants exhibited a deficiency in their ability to recognize happiness in facial pictures, these results did not translate to differences in smoking status. This study elucidates some of the complex interrelations between hostility, emotion processing, and adolescent smoking, which may have implications for teen smoking prevention.

Smoking mull: a grounded theory model on the dynamics of combined tobacco and cannabis use among adult men

ISSUE ADDRESSED

Australians' use of cannabis has been increasing. Over a third of Australians (35.4%) have used cannabis at some time in their lives and 10.3% are recent users. Almost two-thirds of cannabis users combine cannabis with tobacco. The aim of this study was to understand the process of mulling - smoking tobacco and cannabis together - using a grounded theory approach.

METHODS

Twenty-one in-depth semistructured interviews were conducted with men aged 25-34 and living on the North Coast of New South Wales. Interviews explored participants' smoking practices, histories and cessation attempts.

RESULTS

A model describing mulling behaviour and the dynamics of smoking cannabis and tobacco was developed. It provides an explanatory framework that demonstrates the flexibility in smoking practices, including substance substitution - participants changed the type of cannabis they smoked, the amount of tobacco they mixed with it and the devices they used to smoke according to the situations they were in and the effects sought.

CONCLUSION

Understanding these dynamic smoking practices and the importance of situations and effects, as well as the specific role of tobacco in mulling, may allow health workers to design more relevant and appropriate interventions. SO WHAT? Combining tobacco with cannabis is the most common way of smoking cannabis in Australia. However, tobacco cessation programmes rarely address cannabis use. Further research to develop evidence-based approaches for mull use would improve cessation outcomes.

Relief of cannabis withdrawal symptoms and cannabis quitting strategies in people with schizophrenia

This study examined the response to cannabis withdrawal symptoms and use of quitting strategies to maintain abstinence in people with schizophrenia. A convenience sample of 120 participants with schizophrenia who had at least weekly cannabis use and a previous quit attempt without formal treatment were administered the 176-item Marijuana Quit Questionnaire to characterize their "most serious" (self-defined) quit attempt. One hundred thirteen participants had withdrawal symptoms, of whom 104 (92.0%) took some action to relieve a symptom, most commonly nicotine use (75%). 90% of withdrawal symptoms evoked an action for relief in a majority of participants experiencing them, most frequently anxiety (95.2% of participants) and cannabis craving (94.4%). 96% of participants used one or more quitting strategies to maintain abstinence during their quit attempt, most commonly getting rid of cannabis (72%) and cannabis paraphernalia (67%). Religious support or prayer was the quitting strategy most often deemed "most helpful" (15%). Use of a self-identified most helpful quitting strategy was associated with significantly higher one-month (80.8% vs. 73.6%) and one-year (54.9% vs. 41.3%) abstinence rates. Actions to relieve cannabis withdrawal symptoms in people with schizophrenia are common. Promotion of effective quitting strategies may aid relapse prevention.

Smoking and other drug characteristics of aboriginal and non-aboriginal prisoners in australia

Introduction and Aim. Although tobacco and alcohol use have declined substantially in the Australian community, substance use among prisoners remains high. The aim was to compare the smoking, drug, and alcohol characteristics, sociodemographic profile, and general health of Aboriginal and non-Aboriginal male prisoners in a smoking cessation intervention. Design and Methods. This study was a descriptive cross-sectional analysis of data from 425 male prisoners who joined a quit smoking trial conducted at 18 correctional centres in NSW and Queensland using data collected by standardised self-report instruments. Results. Average age was 33 years with 15% from Aboriginal descent. Compared to non-Aboriginal prisoners, Aboriginal prisoners were significantly more likely to have left school with no qualifications, to have been institutionalised as a child, to be previously incarcerated, and commenced smoking at a younger age. The tobacco use profile of both groups was similar; most of them had a medium to high level of nicotine dependence, smoked roll your own tobacco, and were “serious” about quitting. Discussion and Conclusion. Despite differences in terms of sociodemographic characteristics and offending history, the smoking characteristics of Aboriginal and non- Aboriginal prisoners were similar. Incarceration offers an opportunity to encourage smoking cessation and reduction of drug use.

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

AIMS

  Cannabis and tobacco use and misuse frequently co-occur. This review examines the epidemiological evidence supporting the life-time co-occurrence of cannabis and tobacco use and outlines the mechanisms that link these drugs to each other. Mechanisms include (i) shared genetic factors; (ii) shared environmental influences, including (iii) route of administration (via smoking), (iv) co-administration and (v) models of co-use. We also discuss respiratory harms associated with co-use of cannabis and tobacco, overlapping withdrawal syndromes and outline treatment implications for co-occurring use.

METHODS

  Selective review of published studies.

RESULTS

  Both cannabis and tobacco use and misuse are influenced by genetic factors, and a proportion of these genetic factors influence both cannabis and tobacco use and misuse. Environmental factors such as availability play an important role, with economic models suggesting a complementary relationship where increases in price of one drug decrease the use of the other. Route of administration and smoking cues may contribute to their sustained use. Similar withdrawal syndromes, with many symptoms in common, may have important treatment implications. Emerging evidence suggests that dual abstinence may predict better cessation outcomes, yet empirically researched treatments tailored for co-occurring use are lacking.

CONCLUSIONS

  There is accumulating evidence that some mechanisms linking cannabis and tobacco use are distinct from those contributing to co-occurring use of drugs in general. There is an urgent need for research to identify the underlying mechanisms and harness their potential etiological implications to tailor treatment options for this serious public health challenge.

Alcohol and marijuana use in the context of tobacco dependence treatment: impact on outcome and mediation of effect

INTRODUCTION

Alcohol and marijuana are among the most commonly used substances together with tobacco worldwide, but their relationship to smoking cessation is unclear. Although alcohol use decreases the likelihood of abstinence from tobacco, mechanisms of this effect have not been identified. Moreover, a small literature has yielded inconsistent findings regarding the effect of marijuana use on tobacco dependence treatment outcome. The aims of this study were to test increased positive-reinforcement smoking urge as a mediator of the relationship between alcohol and cigarette use and evaluate the impact of marijuana use on abstinence from tobacco.

METHODS

Participants were adult cigarette smokers (N = 739) from 3 randomized clinical trials of smoking cessation treatment. Alcohol consumption and marijuana use were assessed at pretreatment and postcessation. Biochemically verified, 7-day point prevalence smoking abstinence was determined at Weeks 12, 24, 36, and 52, as were urges to smoke as measured by the Questionnaire of Smoking Urges.

RESULTS

Increased positive-reinforcement urge mediated the effect of postcessation alcohol use on smoking abstinence. Although pretreatment alcohol use was associated with a decreased likelihood of abstinence from tobacco, increased positive-reinforcement urge did not account for this relationship. Marijuana use was not associated with abstinence from tobacco.

CONCLUSIONS

Smoking cessation treatments should provide those who drink during a quit attempt techniques designed to mitigate positive-reinforcement urge to smoke. Additional research is needed to determine how pretreatment alcohol consumption exerts its effect on cigarette use. Modifying the use of marijuana might not be critical to the success of tobacco interventions.

Adding tobacco to cannabis--its frequency and likely implications

INTRODUCTION

Young cannabis users are at increased risk of later cigarette initiation and progression to nicotine addiction. The present study addresses the frequency at which mulling (adding tobacco to cannabis smoked as joints) is performed and in which way this practice varies according to cigarette smoking status.

METHODS

Data were issued from the Swiss 2007 European School Survey Project on Alcohol and other Drugs (ESPAD). A total of 881 past month cannabis users (mean age 15 years, boys 60.1%) were inquired on mulling using an anonymous self-administered questionnaire. Participants were further grouped according to their cigarette smoking status (daily, occasional, former, and never-smokers).

RESULTS

Four of every 5 cannabis users depicted mulling as frequently performed. The highest occurrence was found among daily cigarette smokers (DSC; 90.3%), while former cigarette smokers reported the lowest (58.9%). The multinomial logistic regression showed DSC more likely reporting mulling as frequent compared with never-smokers (risk ratio = 3.56 [95% CI 1.55-8.21]).

CONCLUSIONS

Mulling appears to be a very common process among young cannabis users, especially among concomitant cigarette smokers. Nevertheless, the majority of cigarette abstainers also reported frequently adding tobacco to the cannabis they smoke. Because it may represent a significant exposition to nicotine, mulling should be taken into account when assessing substance use among adolescents and in supporting their quitting attempts.

Khat use and neurobehavioral functions: suggestions for future studies

Although there is a rich body of research available regarding the effect of acute and chronic khat dosing in animal models, research on the behavioral and cognitive effects of khat in human subjects is not extensive and several of the available studies have been done only in the context of observational and single-case studies. In light of the absence of a substantial literature on the neurobehavioral deficits associated with khat use and to provide a context that could be used to identify themes for future research we review previous research that has focused on other stimulant drugs. This review highlights multiple areas of neurocognitive deficit that have been identified in previous studies of individuals who have been chronic users of stimulants, such as amphetamines and methamphetamines. The review highlights a substantial body of evidence demonstrating a wide range of learning and memory impairments including deficits that persist during abstinence from active drug use. This review does not imply a similar khat effect, but due to some similarities pharmacologically between the active components of khat (cathinone and cathine) and amphetamines, future studies examining these same domains of cognitive functioning in chronic khat users and abstinent khat users appears to be warranted, if possible using some of the same or similar laboratory measures.

Alcohol, marijuana, and tobacco use among Canadian youth: do we need more multi-substance prevention programming?

Data from the Canadian Youth Smoking Survey (n = 27,030 in 2006; n = 16,705 in 2004; n = 11,757 in 2002) were used to examine changes in the prevalence and comorbid use of alcohol, tobacco, and marijuana over time and examine if demographic factors and binge drinking are associated with comorbid substance use among youth. Alcohol was the most prevalent substance used, and it was rare to find youth who had used tobacco or marijuana without also having tried alcohol. Youth who reported binge drinking were substantially more likely to also have tried tobacco and/or marijuana. These data suggest that multi-substance prevention programs are required for youth populations.

Tobacco and cannabis co-occurrence: does route of administration matter?

BACKGROUND

Qualitative research suggests that a shared route of administration (i.e. via inhalation) for the common forms of both tobacco (i.e. cigarettes) and cannabis (i.e. joints) may contribute to their co-occurring use.

METHODS

We used data on 43,093 U.S. adults who participated in the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) to examine whether cannabis use and abuse/dependence were associated with smoked (cigarettes, cigars, pipes) versus smokeless (snuff, chewed tobacco) forms of tobacco use, even after controlling for socio-demographic, psychiatric and substance-related covariates.

RESULTS

Tobacco smoking was associated with a 3.3-4.5 times increased risk for cannabis use and abuse/dependence respectively. After covariate adjustment, importantly for nicotine dependence, smoking tobacco (but not smokeless tobacco) was still significantly associated with both cannabis use (multinomial odds-ratio (MOR) 1.99) and cannabis dependence (MOR 1.55). In contrast, use of smokeless tobacco was not significantly correlated with elevated rates of cannabis use (MOR 0.96) or abuse/dependence (MOR 1.04).

CONCLUSIONS

Route of administration may play an important role in the observed association between tobacco and cannabis use. This may represent a physiological adaptation of the aero-respiratory system and/or index social and cultural influences surrounding the use of smoked versus smokeless forms of tobacco.

Does marijuana use serve as a gateway to cigarette use for high-risk African-American youth?

BACKGROUND/OBJECTIVES

The purpose of this investigation was to test whether the gateway hypothesis of drug initiation sequencing applies equally well to high-risk African-American and Caucasian youth.

METHODS

The study sample (N = 618, mean age = 15.5, SD = 1.2) represented the population of residents in the Missouri Division of Youth Services (DYS) who had initiated marijuana and nicotine use.

RESULTS

As hypothesized, African-American youth were significantly more likely to initiate marijuana use before cigarette use. Over one-third of African Americans reported initiating marijuana before cigarettes (37.9%), compared to less than one-quarter of youth in the other ethnic groups (Caucasian = 17.3%, Latino/Latina = 21.7%, Biracial/Other = 20.8%). Further, multinomial simulation and logistic regression models revealed that African-American youth were significantly more likely than other ethnic groups to initiate marijuana before cigarettes (Adjusted OR = 3.53, CI = 1.92-6.46). CONCLUSIONS/SCIENTIFIC SIGNIFICANCE: Findings suggest that the hypothesized gateway sequence may not apply equally well to African-Americans, and that prevention efforts based on this theory may need to be amended for these youth.

Smoking tobacco along with marijuana increases symptoms of cannabis dependence

AIM

User practices/rituals that involve concurrent use of tobacco and marijuana - smoking blunts and "chasing" marijuana with tobacco - are hypothesized to increase cannabis dependence symptoms.

DESIGN

Ethnographers administered group surveys to a diverse, purposive sample of marijuana users who appeared to be 17-35 years old.

SETTING

New York City, including non-impoverished areas of Manhattan, the transitional area of East Village/Lower East Side, low-income areas of northern Manhattan and South Bronx, and diverse areas of Brooklyn and Queens.

PARTICIPANTS

481 marijuana users ages 14-35, 57% male, 43% female; 27% White, 30% Black, 19% Latino, 5% Asian, 20% of other/multiple race.

MEASUREMENTS

Among many other topics, group surveys measured cannabis dependence symptoms; frequencies of chasing, blunt smoking, joint/pipe smoking, using marijuana while alone, and general tobacco use; and demographic factors.

FINDINGS

Blunt smoking and chasing marijuana with tobacco were each uniquely associated with five of the seven cannabis dependence symptoms. Across symptoms, predicted odds were 2.4-4.1 times greater for participants who smoked blunts on all 30 of the past 30 days than for participants who did not smoke blunts in the past 30 days. Significant increases in odds over the whole range of the five-point chasing frequency measure (from never to always) ranged from 3.4 times to 5.1 times.

CONCLUSIONS

Using tobacco with marijuana - smoking blunts and "chasing" marijuana with tobacco - contributes to cannabis dependence symptoms. Treatment for cannabis dependence may be more effective it addresses the issue of concurrent tobacco use.

The Mull Hypothesis: is cannabis use contributing to high tobacco use prevalence among young North Coast males?

Men aged 25-34 years, in North Coast NSW, have higher documented smoking rates than elsewhere in the state. The present paper explores potential causes of elevated smoking rates in this population and proposes that tobacco dependence resulting from 'mulling' (mixing) cannabis with tobacco may be contributing.

Subchronic nicotine exposure in adolescence induces long-term effects on hippocampal and striatal cannabinoid-CB1 and mu-opioid receptors in rats

There is evidence for the existence of functional interactions between nicotine and cannabinoids and opioid compounds in adult experimental animals. However, there is scarce information about these relationships in young animals. In the present study we evaluated short and long-term effects of a subchronic nicotine treatment [0.4 mg/kg daily i.p. injections from postnatal day (PND) 34 to PND 43], upon hippocampal and striatal cannabinoid-CB(1) and mu-opioid receptors in Wistar rats of both genders. Rats were sacrificed 2 h after the last nicotine injection (short-term effects, PND 43) or one month later (long-term effects, PND 75). Hippocampal and striatal cannabinoid CB(1) and mu-opioid receptors were quantified by Western blotting. The subchronic nicotine treatment induced a region-dependent long-lasting effect in cannabinoid CB(1) receptor: a significant increase in hippocampal cannabinoid CB(1) receptors and a significant decrease in striatal cannabinoid CB(1) receptors, with these effects being similar in males and females. With respect to mu-opioid receptors, subchronic nicotine induced a significant down-regulation in hippocampal and striatal mu-opioid receptors in the long-term, and within the striatum the effects were more marked in adult males than in females. The present results indicate that juvenile nicotine taking may have implications for the endocannabinoid and endogenous opioid function and for the behaviors served by those systems, this includes possible modification of the response of adults to different psychotropic drugs, i.e. cannabis and morphine/heroin when taken later in life.

Marijuana and tobacco use among young adults in Canada: are they smoking what we think they are smoking?

The authors characterized marijuana smoking among young adult Canadians, examined the co-morbidity of tobacco and marijuana use, and identified correlates associated with different marijuana use consumption patterns. Data were collected from 20,275 individuals as part of the 2004 Canadian Tobacco Use Monitoring Survey. Logistic regression models were conducted to examine characteristics associated with marijuana use behaviors among young adults (aged 15-24). Rates of marijuana use were highest among current smokers and lowest among never smokers. Marijuana use was more prevalent among males, young adults living in rural areas, and increased with age. Young adults who were still in school were more likely to have tried marijuana, although among those who had tried, young adults outside of school were more like to be heavy users. Males and those who first tried marijuana at an earlier age also reported more frequent marijuana use. These findings illustrate remarkably high rates of marijuana use and high co-morbidity of tobacco use among young adult Canadians. These findings suggest that future research should consider whether the increasing popularity of marijuana use among young adults represents a threat to the continuing decline in tobacco use among this population.

Reverse gateways? Frequent cannabis use as a predictor of tobacco initiation and nicotine dependence

AIMS

To examine the risk posed by cannabis use in young people for tobacco use disorders. Specifically we examined whether cannabis use in non-smokers predicted later initiation of tobacco use and whether cannabis use predicted later nicotine dependence in tobacco users.

DESIGN

A 10-year eight-wave cohort study.

SETTING

State of Victoria, Australia.

PARTICIPANTS

A community sample of 1943 participants initially aged 14-15 years.

MEASUREMENTS

Self-report of tobacco and cannabis use was assessed in the teens using a computerized interview assessment and in young adulthood with a CATI assessment. The Fagerström Test for Nicotine Dependence was used to define nicotine dependence.

FINDINGS

For teen non-smokers, at least one report of weekly cannabis use in the teens predicted a more than eightfold increase in the odds of later initiation of tobacco use (OR 8.3; 95% CI 1.9-36). For 21-year-old smokers, not yet nicotine-dependent, daily cannabis use raised the odds of nicotine dependence at the age of 24 years more than threefold (OR 3.6, 1.2, 10) after controlling for possible confounders, including level of tobacco use and subsyndromal signs of nicotine dependence.

CONCLUSIONS

Weekly or more cannabis use during the teens and young adulthood is associated with an increased risk of late initiation of tobacco use and progression to nicotine dependence. If this effect is causal, it may be that a heightened risk of nicotine dependence is the most important health consequence of early frequent cannabis use.

Associations between tobacco and cannabis use in remote indigenous populations in Northern Australia

AIMS

To assess whether cannabis use, recently taken up by many indigenous Australians in remote communities, has reinforced tobacco use.

DESIGN

Cross-sectional study.

SETTING

Three eastern Arnhem Land communities (Northern Territory, NT); total population = 3384, in 2001.

PARTICIPANTS

From 1247 people aged 17-36 years, 190 (120 males, 70 females) were opportunistically recruited.

MEASUREMENTS

Self-reported life-time and current tobacco, cannabis and other substance use were confirmed by local health workers and using clinic records. Participants reported level of substance use, frequency and duration (years used). Associations with tobacco use were calculated (odds ratios: OR) using logistic regression with age, sex, alcohol use and a history of petrol sniffing as confounders.

FINDINGS

In univariate analyses current tobacco users were more likely than non-users to be using cannabis (OR = 3.1, 1.5-6.2, P = 0.002) and this association remained in multivariate analyses (OR = 3.0, 1.4-6.8, P = 0.006). Tobacco use was associated with the number of years of cannabis use (P = 0.035). The likelihood that tobacco users were also cannabis users increased as quantity of cannabis used increased (P = 0.008). Current tobacco use was no more likely in those who initiated cannabis from 1998 onwards than in those who initiated cannabis before 1998 (OR = 1.1, 0.4-3.2, P = 0.881). One-third of life-time users of both tobacco and cannabis initiated their use at or near the same time, and very few of these (12%) had discontinued either cannabis or tobacco.

CONCLUSIONS

Cannabis appears to have influenced the continued use of tobacco in these populations with possible additional burdens for cardiovascular and respiratory diseases and challenges for interventions.