The Influence of Cannabis and Nicotine Co-use on Neuromaturation: A Systematic Review of Adolescent and Young Adult Studies

A preliminary investigation of physical and mental health features of cannabis & nicotine co-use among adolescents and young adults by sex

INTRODUCTION

Cannabis and nicotine/tobacco products (NTP) are commonly co-used in adolescence and young adulthood; however, limited research has been done on predictive health behaviors to co-use. The current study is a preliminary investigation into the relationships of modifiable health behaviors on cannabis and NTP co-use in adolescents and young adults.

METHOD

221 participants (ages 16-22) were characterized into cannabis use only (N = 55), NTP use only (N = 20), cannabis and NTP co-use (used cannabis and NTP; N = 96) and control (no use; N = 50) groups based on past 30-day use. Self-report measures for physical activity, sleep quality, mental health, and reward responsivity were utilized. Participants were given a comprehensive neurocognitive battery. Logistic regressions of self-report measures and fluid intelligence composite scores on substance use group status were run stratified by sex.

RESULTS

Higher approach reward sensitivity traits were associated with increased likelihood of cannabis use only (Odds Ratio (OR) = 1.15, p = .036) in female participants. Increased aerobic activity was associated with decreased likelihood of cannabis use only (OR = 0.91, p = .047) and cannabis and NTP co-use (OR = 0.88, p = .007) in female participants. Higher anxiety was associated with increased likelihood of cannabis NTP co-use (OR = 1.51, p = 0.025) in male participants.

DISCUSSION

Several health behaviors were linked with cannabis use and cannabis and NTP co-use in both females and male adolescents and young adults. Health markers differed by sex suggesting differing mechanisms of substance co-use. This study informs targetable health behaviors for prevention and intervention efforts.

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.

Neurite Orientation Dispersion and Density Imaging (NODDI) of Brain Microstructure in Adolescent Cannabis and Nicotine Use

INTRODUCTION

Despite evidence suggesting deleterious effects of cannabis and nicotine tobacco product (NTP) use on white matter integrity, there have been limited studies examining white matter integrity among users of both cannabis and nicotine. Further, updated white matter methodology provides opportunities to investigate use patterns on neurite orientation dispersion and density (NODDI) indices and subtle tissue changes related to the intra- and extra-neurite compartment. We aimed to investigate how cannabis and NTP use among adolescents and young adults interacts to impact the white matter integrity microstructure.

MATERIALS AND METHODS

A total of 221 participants between the ages of 16 and 22 completed the Customary Drinking and Drug Use Record (CDDR) to measure substance use, and underwent a magnetic resonance imaging (MRI) session. Participants were divided into NTP-control and NTP groupings and cannabis-control and cannabis groupings (≥26 NTP/cannabis uses in past 6 months). Tract-Based Spatial Statistics (TBSS) and two-way between-subjects ANOVA investigated the effects of NTP use group, cannabis use group, and their interaction on fractional anisotropy (FA) and NODDI indices while controlling for age and biological sex.

RESULTS

NTP use was associated with decreased FA values and increased orientation dispersion in the left anterior capsule. There were no significant effects of cannabis use or the interaction of NTP and cannabis use on white matter outcomes.

DISCUSSION

NTP use was associated with altered white matter integrity in an adolescent and young adult sample. Findings suggest that NTP-associated alterations may be linked to altered fiber tract geometry and dispersed neurite structures versus myelination, as well as differential effects of NTP and cannabis use on white matter structure. Future work is needed to investigate how altered white matter is related to downstream behavioral effects from NTP use.

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.

Distress about social problems and tobacco and cannabis use outcomes among young adults in Los Angeles County

OBJECTIVE

To examine associations of concern, worry, and stress about discrimination, shootings/violence, and police brutality and exclusive and dual tobacco and cannabis use among young adults.

METHODS

A prospective, racially/ethnically diverse cohort of young adults (n = 1960) living in Los Angeles, California completed a baseline survey in 2020 (age range: 19-23) and a follow-up survey in 2021. Exploratory factor analysis (EFA) was employed on nine variables assessing levels of concern, worry, and stress about societal discrimination, societal shootings/violence, and community police brutality at baseline. Past 30-day tobacco and cannabis use at follow-up was categorized as current exclusive tobacco, exclusive cannabis, and dual tobacco and cannabis (vs never/former) use based on eleven use variables. Multinomial logistic regressions estimated adjusted associations between each factor score (translated to standard deviation units) with exclusive and dual tobacco and cannabis use.

RESULTS

The EFA produced four factor scores representing concern/worry/stress (i.e., distress) about community police brutality (F1), distress about societal shootings/violence (F2), and distress about societal discrimination (F3), as well as generalized stress about police brutality, shootings/violence, and discrimination (F4). F1, F2, and F3 were associated with subsequent exclusive current cannabis use, with F1 having the strongest association (OR: 1.35, 95% CI: 1.18-1.55), while only F1 (OR: 1.51, 95% CI: 1.27-1.78) was associated with dual tobacco and cannabis use. None of the factors were associated with exclusive tobacco use.

CONCLUSIONS

Young adult concern, worry, and/or stress about social problems may increase risk of cannabis use with or without concurrent tobacco use 6-12 months later.

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.

Prevalence and correlates of past 30-day dual-vaping of nicotine and cannabis among adolescents in five New England states

SIGNIFICANCE

Adolescent vaping behavior includes vaping of multiple substances, including both nicotine and cannabis (dual-vaping). This study describes the prevalence and the sociodemographic correlates of past 30-day dual-vaping.

METHODS

We recruited adolescents ages 13-17 from five New England states (Massachusetts, Connecticut, Rhode Island, Vermont, New Hampshire) through the Prodege online survey panel from April 2021 to August 2022. Dual-vaping was defined as vaping both nicotine and cannabis (THC and/or CBD) in the past 30-days. We analyzed the prevalence of sole-nicotine, sole-cannabis, and dual-vaping of nicotine and cannabis and used multinomial logistic regression to examine associations between sociodemographic factors and sole- and dual-vaping of nicotine and cannabis.

RESULTS

The analytic sample included 2013 observations from 1858 participants (mean age 15.1 years, 46.2% female, 74.1% White, 82.2% heterosexual). Among these observations, 5.6% reported past 30-day sole-nicotine vaping, 5.5% reported sole-cannabis vaping, and 7.3% had dual-vaped. Correlates for higher odds of past 30-day dual-vaping included total social media sites used and household tobacco use, in contrast with sole-cannabis vaping, which included older age and self-reported depression (all p's <0.05).

DISCUSSION

Adolescent past 30-day dual-vaping of nicotine and cannabis was more prevalent than past 30-day sole-vaping of either nicotine or cannabis alone. Future studies should continue to collect detailed data on the type of substances, besides nicotine, that adolescents are vaping.

Age-dependent memory impairment induced by co-exposure to nicotine and a synthetic cannabinoid in mice

Co-use of marijuana and tobacco products is the second most common drug combination among adolescents. Nicotine (NIC) and cannabinoid use during adolescence induce similar detrimental changes, raising the hypothesis that simultaneous exposure could result in even more severe outcomes. Thus, we investigated whether the co-exposure to NIC and the synthetic cannabinoid WIN 55,212-2 (WIN) in adolescent mice causes behavioral outcomes different from those observed after exposure to a single drug. Male Swiss mice were exposed twice daily to NIC, WIN, or NIC + WIN during adolescence (PND28-47) or adulthood (PND70-89). Drug combination led to a greater reduction in weight gain in adolescent mice, while NIC-induced weight loss was observed in adults. During administration, NIC provoked hypothermia, and WIN produced hyperlocomotion in adolescent and adult mice. Animals exposed to NIC + WIN presented a profile of changes similar to those exposed to NIC. After drug exposure, changes in locomotion, thigmotaxis, social preference, prepulse inhibition, and working and recognition memory were evaluated. Adolescent but not adult mice exposed to NIC showed withdrawal-related hyperlocomotion unaffected by WIN co-administration. An age-specific impairment in object recognition memory was induced only by drug co-exposure during adolescence, which resolved spontaneously before reaching early adulthood. A transient decrease in hippocampal α7 nAChR subunit and CB1 receptor mRNA levels was induced by NIC exposure, which may be involved but is not enough to explain the memory impairment. Our work confirms the potential of NIC and cannabinoids association to aggravate some of the individual drug effects during critical neurodevelopmental periods.

Cannabis and Nicotine Dual Use among Sexual Minority Individuals: Relations to Cannabis Use and Negative Affect

Background: Sexual minority individuals report significantly more cannabis use and use-related problems than their heterosexual peers, and emerging data indicate sexual minority individuals who use cannabis are at greater risk for dual use of nicotine products (combustible smoking, e-cigarette use) than heterosexual individuals. Although cannabis-nicotine dual use is related to worse cannabis outcomes and negative affect, little work has identified factors related to dual use among sexual minority individuals or tested if sexual orientation-based discrimination (microaggressions, overt discrimination) is related to dual use. Objectives: The current study tested if cannabis-nicotine dual use is related to more frequent cannabis use, more cannabis-related problems, negative affect, and discrimination among sexual minority undergraduate students who endorsed current (past three-month) cannabis use (N = 328), 43.6% of whom endorsed dual nicotine use. Cannabis-nicotine dual use was related to more frequent cannabis use, more cannabis-related problems, more anxiety (but not depression), and more sexual orientation-based microaggressions and microaggressions-related negative affect (but not overt discrimination or non-sexual orientation-based daily stressors). Conclusions/Importance: Overall, this is the first known study to identify that sexual orientation-based discrimination is related to cannabis-nicotine dual use and that dual use is related to more frequent cannabis use, use-related problems, and negative affect (especially anxiety) among this underrepresented group.

The Association Between Cannabis Use and Subsequent Nicotine Electronic Cigarette Use Among US Adolescents

PURPOSE

The current study assessed the association between cannabis use among youth never e-cigarette users and subsequent e-cigarette use.

METHODS

The Population Assessment of Tobacco and Health Study is a nationally representative cohort study. Participants aged 12 years and older were selected using a 4-stage, stratified probability sample design from the US civilian, noninstitutionalized population. We included adolescents who participated in both wave 4.5 (2017-2018) and wave 5 (2018-2019) of Population Assessment of Tobacco and Health, and were never e-cigarette users at baseline (N = 9,925). Through multivariable logistic regressions, we examined the prospective association between cannabis use and subsequent e-cigarette use.

RESULTS

E-cigarette use at wave five was significantly more common among youth cannabis users at wave 4.5. The adjusted relative risks between ever cannabis use and subsequent past 12-month, past 30-day, and frequent e-cigarette use (≥20 days per month) were 1.53 (95% CI, 1.26-1.81), 1.70 (95% CI, 1.25-2.15), and 2.10 (95% CI, 1.17-3.03), respectively. The adjusted relative risks between past 30-day cannabis use and subsequent past 12-month, past 30-day, and frequent e-cigarette use were 1.54 (95% CI, 1.04-2.28), 2.01 (95% CI, 1.23-3.29), and 2.87 (95% CI, 1.44-5.71), respectively. We also found significant associations between ever cannabis vaping with subsequent e-cigarette use.

DISCUSSION

While previous research associates e-cigarette use with subsequent onset of cannabis use, we identify a reverse directional effect, where adolescent cannabis use is associated with increased likelihood of future e-cigarette use.

E-cigarettes may serve as a gateway to conventional cigarettes and other addictive drugs

Electronic cigarettes (e-cigarettes) are devices that allow the user to inhale nicotine in a vapor, and are primarily marketed as a means of quitting smoking and a less harmful replacement for traditional cigarette smoking. However, further research is needed to determine if vaping nicotine via e-cigarettes can be effective. Conversely, nicotine has been considered a gateway drug to alcohol and other addictive drugs and e-cigarettes containing nicotine may have the same effects. Previous reports have shown that e-cigarette use may open the gate for the use of other drugs including conventional cigarettes, cannabis, opioids, etc. The increasing prevalence of e-cigarettes, particularly among youth and adolescents in the last decade have led to an increase in the dual use of e-cigarettes with alcohol, cannabis, and other illicit drug use like heroin and 3-4-methylenedioxymethamphetamine (MDMA). The advent of e-cigarettes as a device to self-administer addictive agents such as cocaine and synthetic cathinones may bring about additional adverse health effects associated with their concurrent use. This review aims to briefly describe e-cigarettes and their different generations, and their co-use with other addictive drugs as well as the use of the device as a tool to self-administer addictive drugs, such as cocaine, etc.

Organoids: The current status and biomedical applications

Organoids are three-dimensional (3D) miniaturized versions of organs or tissues that are derived from cells with stem potential and can self-organize and differentiate into 3D cell masses, recapitulating the morphology and functions of their in vivo counterparts. Organoid culture is an emerging 3D culture technology, and organoids derived from various organs and tissues, such as the brain, lung, heart, liver, and kidney, have been generated. Compared with traditional bidimensional culture, organoid culture systems have the unique advantage of conserving parental gene expression and mutation characteristics, as well as long-term maintenance of the function and biological characteristics of the parental cells in vitro. All these features of organoids open up new opportunities for drug discovery, large-scale drug screening, and precision medicine. Another major application of organoids is disease modeling, and especially various hereditary diseases that are difficult to model in vitro have been modeled with organoids by combining genome editing technologies. Herein, we introduce the development and current advances in the organoid technology field. We focus on the applications of organoids in basic biology and clinical research, and also highlight their limitations and future perspectives. We hope that this review can provide a valuable reference for the developments and applications of organoids.

Association between use of electronic vaping products and insufficient sleep among adolescents: Findings from the 2017 and 2019 YRBS

BACKGROUND AND OBJECTIVE

Although studies have investigated the association between cigarette smoking and sleep outcomes among adolescents in the United States, few studies have examined the association between electronic vaping products (EVPs) use and insufficient sleep among adolescents. The objective of this study was to investigate the cross-sectional association between the use of EVPs and insufficient sleep among adolescents.

METHODS

Data were pooled from the 2017 and 2019 Youth Risk Behavior Survey. An analytic sample of 28,135 adolescents (51.2% female) was analyzed using binary logistic regression. The dependent variable investigated was insufficient sleep, and the main independent variable was the use of EVPs.

RESULTS

Of the 28,135 adolescents, 22.6%, 19.2%, and 58.2% were current, former, and never users of EVPs, respectively. More than three in four adolescents (76.5%) did not obtain the recommended 8 h of sleep on an average school night. Controlling for demographic factors and other covariates, adolescents who currently used EVPs had 1.33 times higher odds of having insufficient sleep (AOR = 1.33, p < .001, 95% CI = 1.16-1.52), and adolescents who previously used EVPs had 1.29 times higher odds of having insufficient sleep (AOR = 1.29, p < .001, 95% CI = 1.15-1.44) when compared to adolescents who had never used EVPs. Adolescents were more likely to get insufficient sleep if they were older, non-Hispanic Black, had symptoms of depression, experienced suicidal ideation, engaged in excessive screen-time behaviors, or currently used alcohol. Physical activity had a protective effect on insufficient sleep.

CONCLUSION

This study found that EVPs use was associated with insufficient sleep among adolescents over and above demographic and other covariates. As EVP use increases among adolescents, it is important to consider the potential impact on multiple domains, including sleep. Future studies that employ longitudinal designs may offer additional insight into the mechanisms underlying the association between EVPs use and insufficient sleep.

Chronic cannabis use affects cerebellum dependent visuomotor adaptation

BACKGROUND

Cannabis is one of the most commonly used substances in the world. However, its effects on human cognition are not yet fully understood. Although the cerebellum has the highest density of cannabinoid receptor type 1 (CB1R) in the human brain, literature on how cannabis use affects cerebellar-dependent learning is sparse. This study examined the effect of chronic cannabis use on sensorimotor adaptation, a cerebellar-mediated task, which has been suggested to depend on endocannabinoid signaling.

METHODS

Chronic cannabis users (n = 27) with no psychiatric comorbidities and healthy, cannabis-naïve controls (n = 25) were evaluated using a visuomotor rotation task. Cannabis users were re-tested after 1 month of abstinence (n = 13) to assess whether initial differences in performance would persist after cessation of use.

RESULTS

Cannabis users showed lower adaptation rates compared to controls at the first time point. However, this difference in performance did not persist when participants were retested after one month of abstinence (n = 13). Healthy controls showed attenuated implicit learning in the late phase of the adaptation during re-exposure, which was not present in cannabis users. This explains the lack of between group differences in the second time point and suggests a potential alteration of synaptic plasticity required for cerebellar learning in cannabis users.

CONCLUSIONS

Overall, our results suggest that chronic cannabis users show alterations in sensorimotor adaptation, likely due to a saturation of the endocannabinoid system after chronic cannabis use.

Advanced human developmental toxicity and teratogenicity assessment using human organoid models

Tremendous progress has been made in the field of toxicology leading to the advance of developmental toxicity assessment. Conventional animal models and in vitro two-dimensional models cannot accurately describe toxic effects and predict actual in vivo responses due to obvious inter-species differences between humans and animals, as well as the lack of a physiologically relevant tissue microenvironment. Human embryonic stem cell (hESC)- and induced pluripotent stem cell (iPSC)-derived three-dimensional organoids are ideal complex and multicellular organotypic models, which are indispensable in recapitulating morphogenesis, cellular interactions, and molecular processes of early human organ development. Recently, human organoids have been used for drug discovery, chemical toxicity and safety in vitro assessment. This review discusses the recent advances in the use of human organoid models, (i.e., brain, retinal, cardiac, liver, kidney, lung, and intestinal organoid models) for developmental toxicity and teratogenicity assessment of distinct tissues/organs following exposure to pharmaceutical compounds, heavy metals, persistent organic pollutants, nanomaterials, and ambient air pollutants. Combining next-generation organoid models with innovative engineering technologies generates novel and powerful tools for developmental toxicity and teratogenicity assessment, and the rapid progress in this field is expected to continue.

Gemeinsamer Konsum von Nikotin und Cannabis: eindeutige Effekte fehlen

Der Konsum mehrerer Suchtmittel birgt immer Gefahren, etwa durch Wechselwirkungen und eine erhöhte Suchtgefahr. Ein besonderes Augenmerk wird dabei auf Jugendliche gelegt. Häufig bilden sich Abhängigkeiten in diesem Alter aus; außerdem wirken hier Suchtmittel auf das Gehirn als System in Umbau und Entwicklung. Die Autoren stellen in diesem Review die Frage nach Effekten von gemeinsamem Konsum von Nikotin und Cannabis auf das jugendliche Gehirn.

Gemeinsamer Konsum von Nikotin und Cannabis: eindeutige Effekte fehlen

Der Konsum mehrerer Suchtmittel birgt immer Gefahren, etwa durch Wechselwirkungen und eine erhöhte Suchtgefahr. Ein besonderes Augenmerk wird dabei auf Jugendliche gelegt. Häufig bilden sich Abhängigkeiten in diesem Alter aus; außerdem wirken hier Suchtmittel auf das Gehirn als System in Umbau und Entwicklung. Die Autoren stellen in diesem Review die Frage nach Effekten von gemeinsamem Konsum von Nikotin und Cannabis auf das jugendliche Gehirn.

Tobacco and Nervous System Development and Function-New Findings 2015-2020

Tobacco is a one of the most common addictive stimulants used by people around the world. The smoke generated during tobacco combustion is a toxic mixture of more than 5000 chemicals of which over 30 are known human carcinogens. While its negative effects on the human body are well understood, it remains a serious public health problem. One of the multiple effects of smoking is tobacco’s effect on the nervous system—its development and function. This review aims to summarize the progress made in research on the effects of tobacco on the nervous system both of the perinatal period and adults and both in animals and humans in 2015–2020. The 1245 results that corresponded to the keywords “tobacco, cigarette, nervous system, brain, morphology, function” were reviewed, of which 200 abstracts were considered significant. Most of those articles broadened the knowledge about the negative effects of smoking on the human nervous system. Tobacco has a significant negative impact on the development of nervous structures, neurotransmission and cognitive functions, and promotes the development of neurodegenerative diseases, insomnia and cerebrovascular diseases. The only exception is the protective effect of the dopaminergic system in Parkinson’s disease. In conclusion, in recent years much effort has been devoted to describing, revealing and uncovering new aspects of tobacco detrimental to human life. The nicotine contained in tobacco smoke affects the human body in a multidimensional way, including a serious impact on the broadly understood neurological health.