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

Trends in the use of cigarettes, cigars, and marijuana among students with and without asthma, 2003-2017

Aim: Asthma has symptoms that can be exacerbated by using combustible products such as tobacco and marijuana. This study assessed the prevalence and trends in current use of cigarettes, cigars, and marijuana among U.S. high school students with and without asthma. Methods: The national Youth Risk Behavior Survey (YRBS) is a biennial, school-based, nationally representative survey of U.S. students in grades 9-12. Trends during 2003-2017 in current (past 30-day) use of cigarettes, cigars, and marijuana among students with and without asthma were examined using logistic regression. Asthma was defined as reporting that a doctor or nurse ever told the student they had asthma. T-tests were used to compare cigarette, cigar, and marijuana use by asthma status and year, frequency of use, and student characteristics. Results: During 2003-2017, both current cigarette and cigar smoking decreased (p < 0.05) with rates that were similar among students with and without asthma. There was no significant linear change in current marijuana use, irrespective of asthma status. During most years, cigarette, cigar, and marijuana use were more common among students with asthma than without. In 2017, the most frequent use of cigarettes, cigars, and marijuana was among those with asthma than without. Differences in cigarette, cigar, and marijuana use by asthma status were apparent by demographic subgroups. Conclusions: Given the adverse respiratory effects of tobacco and marijuana smoking, efforts to educate all youth about the dangers of using these substances is critical, particularly among those with asthma.

Modes of delivery in concurrent nicotine and cannabis use ("co-use") among youth: Findings from the International Tobacco Control (ITC) Survey

BACKGROUND

Cannabis use is more common among nicotine users than non-users. This study characterized concurrent use of nicotine and cannabis ("co-use") among 12,064 youth aged 16-19 years residing in Canada, the United States, and England in 2017. Methods: Data were from the ITC Youth Tobacco & Vaping Survey (Wave 1). Seven modes of cannabis delivery (MOD) were characterized by country of residence and past 30-day use of combusted tobacco and electronic cigarettes. Weighted multivariable regression models were fitted to assess the correlates of co-use and each cannabis MOD. Results: Seventy percent of cannabis users reported nicotine use. Co-users exhibited behavioral and demographic differences compared to exclusive users of either substance. "Smoking cannabis without tobacco" was the most popular form of use (78%). Use of nicotine-containing e-cigarettes was associated with "using an e-cigarette to vape cannabis oil/liquid" (aOR: 4.96, 95%CI: 2.23-11.06). Combustible tobacco use was associated with "smoking cannabis with tobacco in a joint/blunt" (aOR: 2.93, 95%CI: 1.89-4.56). Country-level differences were detected. Conclusions: Nicotine use is substantial among cannabis users, and associations exist between modes of delivery for both drugs. Results underscore the importance of studying cannabis and nicotine use concurrently, and the need to address the use of both substances in developing interventions for youth users.

Quantitative biochemical screening for marijuana use and concordance with tobacco use in urban adolescents

BACKGROUND

Assessing the prevalence and level of exposure (dose) of tobacco and marijuana use is important in studies of harm from use of these substances. We used biochemical analysis of urine to quantitatively assess exposure to nicotine and delta 9-tetrahydrocannabinol (THC) in adolescents receiving medical care in a public hospital METHODS: Participants were 686 adolescents between 12 and 21 years old seen at Zuckerberg San Francisco General Hospital between 2012 and 2014. Urine samples were assayed using high sensitivity liquid chromatographic assays for cotinine, a major metabolite of nicotine, and 11-nor-9-carboxy-delta 9-THC (THC-COOH), a major metabolite of THC. A commonly used immunoassay screen for THC-COOH was also performed.

RESULTS

The THC-COOH immunoassay substantially underestimated THC exposure, as measured with the high sensitivity assay. THC use was detected in 25% of participants, with higher prevalence with increasing age and in non-Hispanic blacks. Active tobacco smokers had an 80% prevalence of THC use (odds ratio for cigarette smoking predicting THC use 13.2). Urine cotinine and THC-COOH were significantly correlated (r = 0.60).

CONCLUSIONS

The use of a high sensitivity chromatographic urine assay provides a much more complete picture of adolescent tobacco use compared to a commonly used immunoassay. The immunoassay provides high specificity but moderate sensitivity. We confirm high concordance of tobacco and marijuana use and the high predictive value of cigarette smoking in predicting marijuana use, and provide novel data on the quantitative correlation between level of exposure to nicotine and THC. Quantitative screening of nicotine and THC exposure may enhance our understanding of addiction and harm from single and dual product use.

Cannabis and tobacco use and co-use: Trajectories and correlates from early adolescence to emerging adulthood

BACKGROUND

Cannabis and tobacco co-use is a growing concern, yet little is known about its developmental course or associated outcomes during emerging adulthood. This study examines developmental trajectories of cannabis and tobacco co-use from adolescence to emerging adulthood, associations of co-use trajectories with four domains of functioning, and differences across racial/ethnic groups.

METHODS

Survey data come from a racially/ethnically diverse and predominantly California-based cohort that completed 10 surveys from 2008 (wave 1: mean age 11.5; n = 6,509) to 2018 (wave 10: mean age 20.7; n = 2,429). Co-use was defined as use of both cannabis and tobacco (cigarettes or smokeless tobacco) in the past 30 days. Trajectories of use were examined using latent growth modeling in a structural equation modeling framework.

RESULTS

Prevalence of cannabis and tobacco co-use increased from 0.3% at wave 1 to 9.5% at wave 10, with average probabilities of co-use higher among non-Hispanic white versus Hispanic or Asian participants. Higher average probability of co-use was associated with greater delinquency, more mental health symptoms, and poorer physical health during emerging adulthood. Higher rate of change in the probability of co-use over time was associated with greater delinquency, but better social functioning and less physical ailments. There was some evidence of racial/ethnic disparities in functioning, even at similar levels of co-use.

CONCLUSIONS

Cannabis and tobacco co-use deserves greater attention, especially regarding its effects on functioning during emerging adulthood. Results also emphasize the need for future research to focus on racial/ethnic disparities related to co-use and associated outcomes.

Past 30-day co-use of tobacco and marijuana products among adolescents and young adults in California

BACKGROUND

Limited research among adolescents and young adults (AYA) has assessed tobacco and marijuana co-use in light of specific products. We examined the patterns of past 30-day co-use of tobacco and marijuana products, and the product-specific associations among past 30-day use of these substances.

METHODS

Data from three school-based convenience samples of California AYA (aged 15-22) (Sample 1 = 3008; Sample 2 = 1419; Sample 3 = 466) were collected during 2016-2017. Proportions of past 30-day co-use of tobacco (e-cigarettes, cigarettes, hookah, cigars) and marijuana (combustible, vaporized, edible, blunt) were estimated. Multivariable logistic regression analyses examined associations between use of each tobacco and marijuana product for individual samples, then the pooled analysis calculated combined ORs.

RESULTS

In the three samples, 7.3-11.3% of participants reported past 30-day co-use. Combinations of e-cigarettes or cigarettes and combustible marijuana were the most common co-use patterns. Past 30-day use of e-cigarettes or cigarettes (vs. non-use) increased the odds of past 30-day use of all marijuana products [e-cigarettes: ORs (95%CI) ranging from 2.5 (1.7, 3.2) for edible marijuana to 4.0 (2.8, 5.2) for combustible marijuana; cigarettes: from 3.2 (2.1, 4.2) for vaporized marijuana to 5.5 (3.8, 7.3) for combustible marijuana]. Past 30-day use of hookah or cigars was positively associated with past 30-day use of three of four marijuana products, except for hookah and vaporized marijuana, and for cigars and combustible marijuana.

CONCLUSIONS

Given various co-use patterns and significant associations among tobacco and marijuana products, interventions targeting AYA should address co-use across the full spectrum of specific products for both substances.

Consequences of Perinatal Cannabis Exposure

Cannabis exposure during the perinatal period results in varied and significant consequences in affected offspring. The prevalence of detrimental outcomes of perinatal cannabis exposure is likely to increase in tandem with the broadening of legalization and acceptance of the drug. As such, it is crucial to highlight the immediate and protracted consequences of cannabis exposure on pre- and postnatal development. Here, we identify lasting changes in neurons' learning flexibility (synaptic plasticity) and epigenetic misregulation in animal models of perinatal cannabinoid exposure (using synthetic cannabinoids or active components of the cannabis plant), in addition to significant alterations in social behavior and executive functions. These findings are supported by epidemiological data indicating similar behavioral outcomes throughout life in human offspring exposed to cannabis during pregnancy. Further, we indicate important lingering questions regarding accurate modeling of perinatal cannabis exposure as well as the need for sex- and age-dependent outcome measures in future studies.

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.

Tobacco and cannabis co-use: Drug substitution, quit interest, and cessation preferences

The co-use of tobacco and cannabis is a common practice worldwide and carries with it substantial public health burden. Few interventions exist that target both substances and little is known about quit interest, treatment preferences, and drug substitution during past cessation attempts, which is critical to guide the development of treatment strategies. The goal of this study was to provide descriptive information regarding quit interest, treatment preferences, and perceived drug substitution among adult (age 18 +) cannabis-tobacco co-users. Participants (N = 282) from two independent survey samples (recruited from Amazon Mechanical Turk) from across the United States were combined. Among all participants, 57% were female, 79% were White, and average age was 33.31 (SD = 9.54) years old. Approximately 80% had tried to quit smoking cigarettes at least once, while 40% had tried to quit using cannabis at least once. Of those who tried to quit, 50% self-reported a perceived increase in their cannabis use during tobacco cessation and 62% self-reported a perceived increase in their tobacco use during cannabis cessation. Average quit interest (10-point scale) for cannabis was 2.39 (SD = 2.35) and for tobacco was 7.07 (SD = 2.90). Results of this study suggest that tobacco use should be addressed among cannabis-tobacco co-users, but interventions should consider lack of interest in cannabis cessation. Reduction-based strategies for cannabis use appear to be more acceptable to this nontreatment-seeking, co-using population. Drug substitution during quit attempts for one substance should be further explored as an important treatment consideration. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Prenatal cannabinoid exposure and altered neurotransmission

Marijuana is one of the most commonly used illicit drugs worldwide. In addition, use of synthetic cannabinoids is increasing, especially among adolescents and young adults. Although human studies have shown that the use of marijuana during pregnancy leads to adverse behavioral effects, such as deficiencies in attention and executive function in affected offspring, the rate of marijuana use among pregnant women is steadily increasing. Various aspects of human behavior including emotion, learning, and memory are dependent on complex interactions between multiple neurotransmitter systems that are especially vulnerable to alterations during the developmental period. Thus, exploration of neurotransmitter changes in response to prenatal cannabinoid exposure is crucial to develop an understanding of how homeostatic imbalance and various long-term neurobehavioral deficits manifest following the abuse of marijuana or other synthetic cannabinoids during pregnancy. Current literature confirms that vast alterations to neurotransmitter systems are present following prenatal cannabinoid exposure, and many of these alterations within the brain are region specific, time-dependent, and sexually dimorphic. In this review, we aim to provide a summary of observed changes to various neurotransmitter systems following cannabinoid exposure during pregnancy and to draw possible correlations to reported behavioral alterations in affected offspring.

Emerging Trends in Cannabis Administration Among Adolescent Cannabis Users

PURPOSE

The legal landscape of cannabis availability and use in the United States is rapidly changing. As the heterogeneity of cannabis products and methods of use increases, more information is needed on how these changes affect use, especially in vulnerable populations such as youth.

METHODS

A national sample of adolescents aged 14-18 years (N = 2,630) were recruited online through advertisements displayed on Facebook and Instagram to complete a survey on cannabis. The survey assessed patterns of edible use, vaping, and smoking cannabis, and the associations among these administration routes and use of other substances.

RESULTS

The most frequent and consistent route of cannabis use was smoking (99% lifetime), with substantial numbers reporting vaping (44% lifetime) and edible use (61% lifetime). The majority of those who had experimented with multiple routes of cannabis administration continued to prefer smoking, and the most common pattern of initiation was smoking, followed by edibles and then vaping. In addition to cannabis use, adolescents reported high rates of nicotine use and substantial use of other substances. Adolescents who used more cannabis administration routes tended to also report higher frequency of other substances tried.

CONCLUSIONS

Additional work is needed to determine whether the observed adolescent cannabis administration patterns are similar across different samples and sampling methods as well as how these trends change over time with extended exposure to new products and methods. The combined knowledge gained via diverse sampling strategies will have important implications for the development of regulatory policy and prevention and intervention efforts.

Tobacco and cannabis co-use and interrelatedness among adults

Cannabis and tobacco co-use is prevalent, but consensus regarding the reasons for co-use among adults and the degree of interrelatedness between these substances is lacking. Reasons for co-use have been explored with younger users, but little data exists for more experienced users with entrenched patterns of co-use. The goal of this study was to examine characteristics and patterns of cannabis-tobacco co-use among adults in the Southeastern United States (US), where there is a legal landscape of generally restrictive cannabis legislation coupled with more permissive tobacco control compared to other US regions. Participants (N = 432) were regular cannabis users recruited through Amazon Mechanical Turk. Measures included demographics, patterns of cannabis and tobacco use, and reasons for co-use. Within this sample, 42% were current users of tobacco (n = 182). Cannabis-tobacco co-users were older and had more years of cannabis use than cannabis-only users. Among the co-using sub-sample, there was little consistency in the reasons for co-use, suggesting individual differences in the use of both substances. High levels of cannabis-tobacco interrelatedness (i.e., temporally concurrent use) were associated with smoking more cigarettes (tobacco) per day and greater nicotine dependence scores when compared to users with low levels of interrelatedness. Though these results are limited by a small sample size and generalizability issues, there were individual differences in cannabis-tobacco relatedness, which may be of importance when considering treatment strategies for cannabis, tobacco, or both. With additional research, personalized strategies adapted to cannabis-tobacco relatedness profiles among co-users may be warranted as a treatment strategy.

Trends in cannabis use over time among Canadian youth: 2004-2014

Cannabis is the most commonly used illicit substance among Canadian youth. The current study examined national trends in cannabis use among Canadian youth from 2004/05 to 2014/15 using nationally representative data from the Canadian Student Tobacco, Alcohol and Drugs Survey (CSTADS). Data were collected from students in Grades 7 to 12 as part of the Canadian Student Tobacco, Alcohol and Drugs Survey (formerly the Youth Smoking Survey) using a repeat-cross sectional survey across 6 biennial survey waves between 2004 and 2014 (N = 243,057). Regression models examined factors associated with cannabis use in the past 12 months, perceived ease of access, and a multilinear regression examined age of initiation across survey cycles. The findings indicate that use of cannabis in the past 12-months significantly decreased among Canadian youth. Past-year use peaked in 2008/09 at 27.3%; compared to 16.5%, in 2014/15. Mean age of initiation did not vary over time, while youth in recent cycles reported that cannabis was more difficult to access: in 2006/07, 77.1% reported that it would be easy to access cannabis compared to 49.0% in 2014/15. Overall, cannabis use among Canadian youth appears to have peaked around 2008/09, with substantial declines over the past decade. It will be critically important to examine any changes in patterns of use following legalization of non-medical cannabis in Canada.

Co-use of cannabis, tobacco, and alcohol during adolescence: policy and regulatory implications

Legislative reforms have legalized use of cannabis for medical and recreational purposes. Efforts to evaluate the public health impact of these changes have predominantly focused on determining whether liberalizing cannabis policies has increased cannabis use patterns. Co-use of cannabis and other licit substances, namely tobacco and alcohol, is common during the developmental period of adolescence, which is generally characterized by an increase in risk-taking and novelty-seeking. However, limited research has sought to evaluate the potential implications of reforms to medical and recreational cannabis laws on concurrent and simultaneous use of cannabis, tobacco, and alcohol during adolescence. The current report reviews the extant literature detailing the prevalence and outcomes associated with concurrent and simultaneous cannabis-tobacco and cannabis-alcohol use, including recent work that has examined how concurrent and simultaneous use may be influenced by cannabis reform. This review details how the cannabis landscape and cannabis retail marketplace have evolved and briefly summarizes the corresponding policy and regulatory challenges that have emerged. The report concludes with a focused cannabis co-use research agenda that adopts different strategies including behavioural economic, self-administration, and survey research methods.