Course of comorbidity of tobacco and marijuana use: psychosocial risk factors

Inhibition of Nicotine Metabolism by Cannabidiol (CBD) and 7-Hydroxycannabidiol (7-OH-CBD)

Cannabis-based products have experienced notable increases in co-usage alongside tobacco products. Several cannabinoids exhibit inhibition of a number of cytochrome P450 (CYP) and UDP glucuronosyltransferase (UGT) enzymes, but few studies have examined their inhibition of enzymes involved in nicotine metabolism. The goal of the present study was to examine potential drug-drug interactions occurring in the nicotine metabolism pathway perpetrated by cannabidiol (CBD) and its active metabolite, 7-hydroxy-CBD (7-OH-CBD). The inhibitory effects of CBD and 7-OH-CBD were tested in microsomes from HEK293 cells overexpressing individual metabolizing enzymes and from human liver tissue. Assays with overexpressing microsomes demonstrated that CBD and 7-OH-CBD inhibited CYP-mediated nicotine metabolism. Binding-corrected IC50,u values for CBD inhibition of nicotine metabolism to cotinine and nornicotine, and cotinine metabolism to trans-3'-hydroxycotinine (3HC), were 0.27 ± 0.060, 0.23 ± 0.14, and 0.21 ± 0.14 μM, respectively, for CYP2A6; and 0.26 ± 0.17 and 0.029 ± 0.0050 μM for cotinine and nornicotine formation, respectively, for CYP2B6. 7-OH-CBD IC50,u values were 0.45 ± 0.18, 0.16 ± 0.08, and 0.78 ± 0.23 μM for cotinine, nornicotine, and 3HC formation, respectively, for CYP2A6, and 1.2 ± 0.44 and 0.11 ± 0.030 μM for cotinine and nornicotine formation, respectively, for CYP2B6. Similar IC50,u values were observed in HLM. Inhibition (IC50,u = 0.37 ± 0.06 μM) of 3HC to 3HC-glucuronide formation by UGT1A9 was demonstrated by CBD. Significant inhibition of nicotine metabolism pathways by CBD and 7-OH-CBD suggests that cannabinoids may inhibit nicotine metabolism, potentially impacting tobacco addiction and cessation.

Electronic cigarette use in adolescence is associated with later cannabis use

BACKGROUND

Research is needed to determine whether e-cigarette use during adolescence is associated with higher odds of subsequent cannabis use, net of tobacco cigarette use and childhood confounders.

METHODS

Multivariable logistic regressions predicting using cannabis by age 17 based upon prospective, intergenerational data from 10,251 youth in a nationally representative UK birth cohort followed from infancy who had not used cannabis by age 14. The focal predictor is e-cigarette use by age 14 in the context of the potential confounder tobacco cigarette use. Regressions include sociodemographic background and risk factors assessed at age 11 (e.g., alcohol initiation, problem behaviors, parental and peer smoking) and during early childhood (e.g., maternal smoking during pregnancy, parental substance use).

RESULTS

Youth use of e-cigarettes by age 14 was associated with 2.8 times higher odds of subsequent cannabis use by age 17 [OR 2.75; 95% CI 1.82,4.15], net of tobacco cigarette smoking and childhood confounders. Similarly, use of e-cigarettes by age 14 was associated with 2.5 times higher odds [OR 2.46; 95% CI 1.48,4.08] of frequent cannabis use at age 17 (>10 times in prior year). If youth used both e-cigarettes and tobacco cigarettes by age 14, the probabilities of cannabis initiation were 75% and of frequent use was 25% by age 17, compared to probabilities of 23% and 6%, respectively, among youth who had used neither product.

CONCLUSIONS

Findings add to accumulating evidence that adolescent e-cigarette use is associated with higher odds of later cannabis initiation and frequent use, independent of tobacco cigarette use.

Reasons for individual and concurrent use of vaped nicotine and cannabis: their similarities, differences, and association with product use

BACKGROUND

Understanding similarities, differences, and associations between reasons people vape nicotine and cannabis may be important for identifying underlying contributors to their co-use.

METHODS

A cross-sectional survey of 112 co-users of vaped nicotine and cannabis was conducted in 2020. A convenience sample of participants was recruited for the survey using Amazon Mechanical Turk. Participants responded to questions about their reasons for individual nicotine and cannabis product use and co-use and rated their level of agreement using numerical scales. Mean ratings for each reason for use subscale were examined across all participants and compared using paired samples t tests. Associations between reasons for use ratings and product consumption behaviors were examined using linear and logistic regression analyses.

RESULTS

Cannabis vaping and smoking exhibited similar mean ratings for user experience and product/substance-related reasons for use. Mean ratings for reasons related to product utility were similar for cannabis vaping and nicotine vaping. Mean ratings for utility-related reasons for use were higher for cannabis vaping than cannabis smoking (mean (SD), 3.6 (± 1.0) vs. 2.6 (± 1.2), p < 0.0001). On average, harm reduction-related reasons for use were rated higher for nicotine vaping than cannabis vaping (2.4 (± 1.6) vs. 1.8 (± 1.4), p < 0.0001). Regression models showed higher average ratings for utility-related (b = 0.32; 95% CI, 0.03-0.60) and harm reduction-related (b = 0.21; 95% CI, 0.04-0.37) reasons for nicotine vaping were associated with more frequent nicotine vaping (both p < 0.05). Higher average ratings for instrumentality-related reasons for co-use corresponded with more frequent monthly nicotine vaping (b = 0.26; 95% CI, 0.08-0.44) and higher odds of ever chasing cannabis with nicotine (aOR, 3.06; 95% CI, 1.29-7.30).

CONCLUSIONS

Vaping serves purposes that differ by substance; nicotine vaping was more closely related to reducing tobacco smoking-related harms, and cannabis vaping was more closely related to circumventing social problems posed by cannabis smoking. Lifetime sequential co-use practices and more frequent nicotine vaping were associated with enhancing the intoxicating effects of cannabis. While replication of these findings using non convenience-based sampling approaches is warranted, results underscore the need to consider shared and unique aspects of nicotine and cannabis vaping, as well as cross-substance interactions between nicotine and cannabis.

Predictors of cannabis and tobacco co-use in youth: exploring the mediating role of age at first use in the population assessment of tobacco health (PATH) study

Background

Adolescents often use substances such as tobacco and cannabis. Co-use of these substances can lead to physical, mental, and psychosocial difficulties beyond that which would be anticipated by simple additivity of their individual effects.

Methods

We aimed to examine the mediating role of age at first use of cannabis or tobacco (AU) between youth factors of internalizing, externalizing, and sensation seeking and two co-use outcomes (lifetime; last 30 days). Path analytic modeling using data from youth age 12–17 who had tried cannabis or tobacco at least once in their lives and participated in the Population Assessment of Tobacco Health (PATH) waves one and two (collected 2013–2015; n=3,847; approximately 46% female) study allowed us to examine these relationships.

Results

The lifetime use model indicated significant direct (internalizing (B = 0.18), externalizing (B = 0.30), sensation seeking (B = 0.15)) and indirect relationships (internalizing (B = 0.18), externalizing (B = 0.33), sensation seeking (B = 0.10)) between each of the three youth factors, the mediator (AU) and the lifetime co-use outcome (p < 0.05 for all). A direct relationship between AU and lifetime co-use was also observed (B = − 1.54). In the past 30-day use model, significant direct paths from AU (B = − 0.49) and sensation seeking (B = 0.06) to past 30-day use were present (p < 0.05 for all).

Discussion

Examination of mediation by AU in the relationships between youth factors and youth co-use of cannabis and tobacco is an important step in understanding these complex relationships. This study is strengthened by the use of a large, nationally representative sample, yet is limited by several factors, such as the use of a secondary dataset and the use of youth self-report.

Conclusions

Based on the findings, programs or interventions targeting youth factors of internalizing, externalizing, and sensation seeking as well as interventions aiming to stave off AU should promote decreased tobacco and cannabis co-use. Sensation seeking and AU appear to be the most influential factors and should be considered when developing and promoting prevention policies/programs for higher risk youth populations.

Association between cigarette use and adolescents' behavior

OBJECTIVE

To determine the prevalence of cigarette use among adolescents and to identify associated health risk behaviors.

METHODS

This is a cross-sectional study with a representative sample, composed of 1059 adolescents between 13 and 19 years old, enrolled in primary and secondary public schools of Olinda, Pernambuco, in 2014. Information was obtained through self-administered questionnaires (validated version of YRBS 2007). Cigarette experimentation was defined as smoking at least once in life. Adolescents who smoked at least one day within 30 days prior to the survey were considered current smokers. Most students were female and 16 years old or older.

RESULTS

Almost 30% used it in life and about 10% smoked within the 30 days before the survey. Suicidal ideation (PR = 1.51, 95%CI 1.25-1.82), alcohol use (PR = 1.41, 95%CI 1.03-1.92), marijuana (PR = 1.64, 95%CI 1.37-1.96), excessive alcohol consumption (PR = 1.57, 95%CI 1.15-2.16) and sexual experience (PR = 1.78, 95%CI 1.43-2.21) have increased the risk of using cigarettes. Feelings of sadness (PR = 1.70, 95%CI 1.22-2.36), alcohol use (PR=2.40, 95%CI 1.12-5.12), excessive alcohol consumption (PR = 2.5, 95% CI 1.24-5.38), marijuana (PR = 2.31, 95%CI.57-3.39) and cocaine (PR = 1.99, 95%CI.32-3.01) increased the risk of cigarette use within the 30 days before the survey.

CONCLUSIONS

Cigarette use among adolescents from Olinda was high, being considered higher than the national prevalence. Possible factors associated with cigarette use were drug use (alcohol, marijuana, and cocaine) and behaviors related to sexual experience, feelings of sadness and suicidal ideation.

Associations between adolescent cannabis use frequency and adult brain structure: A prospective study of boys followed to adulthood

BACKGROUND

Few studies have tested the hypothesis that adolescent cannabis users show structural brain alterations in adulthood. The present study tested associations between prospectively-assessed trajectories of adolescent cannabis use and adult brain structure in a sample of boys followed to adulthood.

METHODS

Data came from the Pittsburgh Youth Study - a longitudinal study of ˜1000 boys. Boys completed self-reports of cannabis use annually from age 13-19, and latent class growth analysis was used to identify different trajectories of adolescent cannabis use. Once adolescent cannabis trajectories were identified, boys were classified into their most likely cannabis trajectory. A subset of boys (n = 181) subsequently underwent structural neuroimaging in adulthood, when they were between 30-36 years old on average. For this subset, we grouped participants according to their classified adolescent cannabis trajectory and tested whether these groups showed differences in adult brain structure in 14 a priori regions of interest, including six subcortical (volume only: amygdala, hippocampus, nucleus accumbens, caudate, putamen, and pallidum) and eight cortical regions (volume and thickness: superior frontal gyrus; caudal and rostral middle frontal gyrus; inferior frontal gyrus, separated into pars opercularis, pars triangularis, and pars orbitalis; lateral and medial orbitofrontal gyrus).

RESULTS

We identified four adolescent cannabis trajectories: non-users/infrequent users, desisters, escalators, and chronic-relatively frequent users. Boys in different trajectory subgroups did not differ on adult brain structure in any subcortical or cortical region of interest.

CONCLUSIONS

Adolescent cannabis use is not associated with structural brain differences in adulthood.

Varenicline and nabilone in tobacco and cannabis co-users: effects on tobacco abstinence, withdrawal and a laboratory model of cannabis relapse

Tobacco and cannabis co-users (T+CUs) have poor cannabis cessation outcomes, but the mechanisms underlying this are not well understood. This laboratory study examined the effects of (1) the partial nicotinic agonist, varenicline, on tobacco cessation among T+CUs, and (2) varenicline, alone, and when combined with the cannabinoid agonist nabilone, on cannabis withdrawal and a laboratory model of cannabis relapse. Non-treatment-seeking T+CUs were randomized to active-varenicline or placebo-varenicline, and completed a 15-day outpatient phase; varenicline was titrated to 1 mg BID during days 1-8, and participants were instructed to abstain from tobacco during days 9-15. Participants then moved inpatient for 16 days, where they continued their outpatient medication and tobacco abstinence. Inpatient testing included two, 8-day medication periods, where active-nabilone and placebo-nabilone were administered in counterbalanced order, and measures of acute cannabis effects (days 1-2), withdrawal (days 4-5) and 'relapse' (days 6-8) were collected. Participants in the active-varenicline group were more likely to achieve cotinine-verified tobacco abstinence during the outpatient period versus placebo-varenicline group (46 percent versus 24 percent, respectively), and also reported less mood disturbance and cigarette craving while inpatient. Active-nabilone attenuated cannabis withdrawal in both groups but did not affect cannabis relapse. Regression analyses revealed that two tobacco-related variables, i.e. age of first cigarette use, and cigarette craving while inpatient, were independent predictors of cannabis relapse outcomes. Thus, varenicline holds promise in this population, as a tool to examine the effects of tobacco abstinence on cannabis use outcomes, and as a component of smoking cessation treatments targeting T+CUs.

Patterns and Correlates of Tobacco and Cannabis co-use by Tobacco Product Type: Findings from the Virginia Youth Survey

BACKGROUND

Cannabis use is more common among tobacco users than nonusers, and co-use (i.e., use of both substances individually) may be increasing. Better understanding of patterns and correlates of co-use is needed. The current study aimed to compare rates and correlates of tobacco and cannabis co-use by tobacco product among youth.

METHODS

High school students who completed the 2013 Virginia Youth Survey and reported past 30-day tobacco use (cigarette, smokeless tobacco, cigar) were included (n = 1390). Prevalence of past 30-day tobacco-only and cannabis co-use was calculated. Demographic, tobacco, and other substance use characteristics were compared by co-use status. Multivariate logistic regression models examined correlates of co-use overall and by tobacco product.

RESULTS

Over half of tobacco users were co-users. Poly-tobacco use, particularly combusted tobacco, was more prevalent among co-users. Past 30-day alcohol use and lifetime other illegal drug use/prescription drug misuse were common correlates of co-use. Black Non-Hispanic (NH) race/ethnicity was associated with co-use when restricted to cigarette users. "Other" race/ethnicity was associated with co-use in the overall model and when restricted to cigar users. Past 30-day cigarette smoking was associated with co-use in all models except among cigar smoking co-users. Conclusions/Importance: Rates and correlates of tobacco and cannabis co-use were not uniform and differed by tobacco product type. Tobacco and cannabis co-users may be at greater risk for negative health effects associated with inhaled tobacco and other risky substance use. The efficacy of prevention efforts may be improved if risk factors associated with product-specific co-use are considered.

Triple trajectories of alcohol use, tobacco use, and depressive symptoms as predictors of cannabis use disorders among urban adults

Heavy cannabis use is associated with a wide array of physical, mental, and functional problems. Therefore, cannabis use disorders (CUDs) may be a major public health concern. Given the adverse health consequences of CUDs, the present study seeks to find possible precursors of CUDs. The current study consisted of 5 waves of data collection from the Harlem Longitudinal Development Study. Among 816 participants, about half are African Americans (52%), and the other half are Puerto Ricans (48%). We used Mplus to obtain the triple trajectories of alcohol use, tobacco use, and depressive symptoms. Logistic regression analyses were then conducted to examine the associations between the trajectory groups and CUDs. The 5 trajectory groups were (1) moderate alcohol use, high tobacco use, and high depressive symptoms (MHH; 12%); (2) moderate alcohol use, high tobacco use, and low depressive symptoms (MHL; 26%); (3) moderate alcohol use, low tobacco use, and low depressive symptoms (MLL; 18%); (4) low alcohol use, no tobacco use, and high depressive symptoms (LNH; 11%); and (5) low alcohol use, no tobacco use, and low depressive symptoms (LNL; 33%). The MHH, MHL, MLL, and LNH trajectory groups were associated with an increased likelihood of having CUDs compared to the LNL trajectory group after controlling for a number of confounding factors (e.g., CUDs in the late 20s). The findings of the current longitudinal study suggest that treatments designed to reduce or quit drinking as well as smoking and to relieve depressive symptoms may reduce the prevalence of CUDs. (PsycINFO Database Record

Licit and illicit substance use patterns among university students in Germany using cluster analysis

BACKGROUND

The use of multiple licit and illicit substances plays an important role in many university students' lives. Previous research on multiple substance use patterns of university students, however, often fails to examine use of different illicit substances and/or hookah. Our objective was to complement and advance the current knowledge about common consumption patterns regarding illicit substances and hookah use in this group.

METHODS

Students from eight German universities completed an online survey as part of the INSIST study ('INternet-based Social norms Intervention for the prevention of substance use among STudents') regarding their consumption of alcohol, tobacco, hookah, cannabis and other illicit substances. Cluster analysis identified distinct consumption patterns of concurrent and non-concurrent substance use and multinomial logistic regressions described key sociodemographic factors associated with these clusters.

RESULTS

Six homogeneous groups were identified: 'Alcohol Abstainers' (10.8%), 'Drinkers Only' (48.2%), 'Drinkers and Cigarette Smokers' (14.6%), 'Cannabis and Licit Substance Users' (11.2%), 'Hookah Users with Co-Use' (9.8%) and 'Illicit Substance Users with Co-Use' (5.4%). Illicit substance use clustered with the consumption of alcohol, tobacco and cannabis. Hookah use was regularly associated with alcohol consumption, less commonly associated with tobacco or cannabis use and very rarely associated with use of other illicit substances. Individuals consuming licit and illicit substances or hookah were mostly male and lived together with other students. Characteristics such as the number of years an individual had spent studying at a university, subject of study, immigrant background and religious affiliation were less commonly associated with cluster membership.

CONCLUSIONS

Although we found substance use patterns in our sample largely similar to previous reports, we identified an important subgroup of individuals using both illicit and licit substances. These individuals may benefit especially from targeted interventions that focus on modifying addictive behavior patterns.

TRIAL REGISTRATION

DRKS00007635 . Registered 17 December 2014 (retrospectively registered).

Personal Values as a Mediator of Relations Between Perceived Parental Support and Control and Youth Substance Use

BACKGROUND

Tobacco and marijuana smoking are very popular in adolescence and there is a high rate of comorbidity between them, even in young adulthood. Parental support and control may hinder involvement in the use of these substances by promoting conventional values among adolescents.

OBJECTIVES

The present study investigates the relations between family functioning (parental support and control) and psychoactive substance use (tobacco and marijuana smoking) and determines whether these relationships are mediated by personal values (in terms of disapproval of deviance and beliefs about the importance of school, health and religion).

METHODS

175 Italian late adolescents (17 to 20 years old) participated in this two-wave longitudinal study. Data were collected at school through an anonymous questionnaire.

RESULTS

Greater parental control and support were directly associated with lower adolescent tobacco and marijuana use; adolescent acceptance of conventional values mediated the association between parenting and adolescent marijuana use.

CONCLUSION

Findings emphasize the influence of family relationships throughout adolescence. The transmission of conventional values to adolescents may be a critical mechanism through which parenting protects adolescents from substance use, especially marijuana use.

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.

Patterns of Substance Use Across the First Year of College and Associated Risk Factors

Starting college is a major life transition. This study aims to characterize patterns of substance use across a variety of substances across the first year of college and identify associated factors. We used data from the first cohort (N = 2056, 1240 females) of the "Spit for Science" sample, a study of incoming freshmen at a large urban university. Latent transition analysis was applied to alcohol, tobacco, cannabis, and other illicit drug uses measured at the beginning of the fall semester and midway through the spring semester. Covariates across multiple domains - including personality, drinking motivations and expectancy, high school delinquency, peer deviance, stressful events, and symptoms of depression and anxiety - were included to predict the patterns of substance use and transitions between patterns across the first year. At both the fall and spring semesters, we identified three subgroups of participants with patterns of substance use characterized as: (1) use of all four substances; (2) alcohol, tobacco, and cannabis use; and (3) overall low substance use. Patterns of substance use were highly stable across the first year of college: most students maintained their class membership from fall to spring, with just 7% of participants in the initial low substance users transitioning to spring alcohol, tobacco, and cannabis users. Most of the included covariates were predictive of the initial pattern of use, but covariates related to experiences across the first year of college were more predictive of the transition from the low to alcohol, tobacco, and cannabis user groups. Our results suggest that while there is an overall increase in alcohol use across all students, college students largely maintain their patterns of substance use across the first year. Risk factors experienced during the first year may be effective targets for preventing increases in substance use.

Associations between cigarette smoking and cannabis dependence: a longitudinal study of young cannabis users in the United Kingdom

AIMS

To determine the degree to which cigarette smoking predicts levels of cannabis dependence above and beyond cannabis use itself, concurrently and in an exploratory four-year follow-up, and to investigate whether cigarette smoking mediates the relationship between cannabis use and cannabis dependence.

METHODS

The study was cross sectional with an exploratory follow-up in the participants' own homes or via telephone interviews in the United Kingdom. Participants were 298 cannabis and tobacco users aged between 16 and 23; follow-up consisted of 65 cannabis and tobacco users. The primary outcome variable was cannabis dependence as measured by the Severity of Dependence Scale (SDS). Cannabis and tobacco smoking were assessed through a self-reported drug history.

RESULTS

Regression analyses at baseline showed cigarette smoking (frequency of cigarette smoking: B=0.029, 95% CI=0.01, 0.05; years of cigarette smoking: B=0.159, 95% CI=0.05, 0.27) accounted for 29% of the variance in cannabis dependence when controlling for frequency of cannabis use. At follow-up, only baseline cannabis dependence predicted follow-up cannabis dependence (B=0.274, 95% CI=0.05, 0.53). At baseline, cigarette smoking mediated the relationship between frequency of cannabis use and dependence (B=0.0168, 95% CI=0.008, 0.288) even when controlling for possible confounding variables (B=0.0153, 95% CI=0.007, 0.027).

CONCLUSIONS

Cigarette smoking is related to concurrent cannabis dependence independently of cannabis use frequency. Cigarette smoking also mediates the relationship between cannabis use and cannabis dependence suggesting tobacco is a partial driver of cannabis dependence in young people who use cannabis and tobacco.

Marijuana Use from Middle to High School: Co-occurring Problem Behaviors, Teacher-Rated Academic Skills and Sixth-Grade Predictors

Rising marijuana use and its lowered perceived risk among adolescents highlight the importance of examining patterns of marijuana use over time. This study identified trajectories of marijuana use among adolescents followed from middle through high school, characterized these by co-occurring problem behaviors and teacher-rated academic skills (study skills, attention problems, and learning problems), and tested sixth-grade predictors of trajectory membership. The sample consisted of a randomly-selected cohort of 619 students assessed annually from sixth to twelfth grade. Using group-based modeling, we identified four trajectories of marijuana use: Abstainer (65.6%), Sporadic (13.9%), Experimental (11.5%), and Increasing (9.0%). Compared to Abstainers, students in the Sporadic, Experimental and Increasing trajectories reported significantly more co-occurring problem behaviors of alcohol use, cigarette smoking, and physical aggression. Sporadic and Experimental users reported significantly less smoking and physical aggression, but not alcohol use, than Increasing users. Teachers consistently rated Abstainers as having better study skills and less attention and learning problems than the three marijuana use groups. Compared to Abstainers, the odds of dropping out of high school was at least 2.7 times higher for students in the marijuana use trajectories. Dropout rates did not vary significantly between marijuana use groups. In sixth grade, being male, cigarette smoking, physical aggression and attention problems increased the odds of being in the marijuana use trajectories. Multiple indicators--student self-reports, teacher ratings and high school dropout records--showed that marijuana was not an isolated or benign event in the life of adolescents but part of an overall problem behavior syndrome.

Objective and perceived neighborhood characteristics and tobacco use among young adults

BACKGROUND

In the US, past month tobacco use is higher among young adults aged 18-25 years than among any other age group. Neighborhood disorder may be a malleable environmental determinant of tobacco use among young adults; its correlation with tobacco use is understudied. The purpose of this study is to examine whether perceived and objectively measured neighborhood factors are associated with tobacco use among young adults in Baltimore City.

METHODS

This cross-sectional study of predominately African American young adults (n=359) used logistic regression models via generalized estimating equations (GEE) to estimate the association of perceived and objective neighborhood disorder with past month tobacco use, adjusting for race, age, sex, income, and other substance use. Two measures of perceived neighborhood environment - neighborhood drug involvement, and neighborhood social cohesion - were derived from the Neighborhood Environment Scale (NES). Objective neighborhood disorder was measured via trained field raters using the Neighborhood Inventory for Environmental Typology (NIfETy) instrument.

RESULTS

Sex modified the relationship between perceived neighborhood drug involvement and past month tobacco use, and the association was significant among women only (aOR=1.49; 95% CI=1.19-1.88). Perceptions of neighborhood social cohesion (aOR=0.97; 95% CI=0.83-1.13), and objective neighborhood disorder (aOR=1.17; 95% CI=0.98-1.38) were not significantly associated with past month tobacco use.

CONCLUSION

Understanding the correlation between perceived and objective neighborhood disorder, and their independent association with tobacco use can potentially lead to environmentally based interventions aimed at reducing tobacco use among young adults who live in urban environments.

Psychiatric, psychosocial, and physical health correlates of co-occurring cannabis use disorders and nicotine dependence

BACKGROUND

Several gaps in the literature on individuals with co-occurring cannabis and tobacco use exist, including the extent of psychiatric, psychosocial, and physical health problems. We examine these gaps in an epidemiological study, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), of a large, nationally representative sample.

METHODS

The sample was drawn from Wave 2 NESARC respondents (N=34,653). Adults with current cannabis use disorders and nicotine dependence (CUD+ND) (n=74), CUD only (n=100), and ND only (n=3424) were compared on psychiatric disorders, psychosocial correlates (e.g., binge drinking; partner violence), and physical health correlates (e.g., medical conditions).

RESULTS

Relative to those with CUD only, respondents with CUD+ND were significantly more likely to meet criteria for bipolar disorder, Clusters A and B personality disorders, and narcissistic personality disorder, and reported engaging in a significantly higher number of antisocial behaviors. Relative to those with ND only, respondents with CUD+ND were significantly more likely to meet criteria for bipolar disorder, anxiety disorders, and paranoid, schizotypal, narcissistic, and borderline personality disorders; were significantly more likely to report driving under the influence of alcohol and being involved in partner violence; and reported engaging in a significantly higher number of antisocial behaviors. CUD+ND was not associated with physical health correlates.

CONCLUSIONS

Poor treatment outcomes for adults with co-occurring cannabis use disorders and nicotine dependence may be explained in part by differences in psychiatric and psychosocial problems.

A novel method for analyzing genetic association with longitudinal phenotypes

Knowledge of genes influencing longitudinal patterns may offer information about predicting disease progression. We developed a systematic procedure for testing association between SNP genotypes and longitudinal phenotypes. We evaluated false positive rates and statistical power to localize genes for disease progression. We used genome-wide SNP data from the Framingham Heart Study. With longitudinal data from two real studies unrelated to Framingham, we estimated three trajectory curves from each study. We performed simulations by randomly selecting 500 individuals. In each simulation replicate, we assigned each individual to one of the three trajectory groups based on the underlying hypothesis (null or alternative), and generated corresponding longitudinal data. Individual Bayesian posterior probabilities (BPPs) for belonging to a specific trajectory curve were estimated. These BPPs were treated as a quantitative trait and tested (using the Wald test) for genome-wide association. Empirical false positive rates and power were calculated. Our method maintained the expected false positive rate for all simulation models. Also, our method achieved high empirical power for most simulations. Our work presents a method for disease progression gene mapping. This method is potentially clinically significant as it may allow doctors to predict disease progression based on genotype and determine treatment accordingly.

Clinical correlates of co-occurring cannabis and tobacco use: a systematic review

AIMS

  A growing literature has documented the substantial prevalence of and putative mechanisms underlying co-occurring (i.e. concurrent or simultaneous) cannabis and tobacco use. Greater understanding of the clinical correlates of co-occurring cannabis and tobacco use may suggest how intervention strategies may be refined to improve cessation outcomes and decrease the public health burden associated with cannabis and tobacco use.

METHODS

  A systematic review of the literature on clinical diagnoses, psychosocial problems and outcomes associated with co-occurring cannabis and tobacco use. Twenty-eight studies compared clinical correlates in co-occurring cannabis and tobacco users versus cannabis- or tobacco-only users. These included studies of treatment-seekers in clinical trials and non-treatment-seekers in cross-sectional or longitudinal epidemiological or non-population-based surveys.

RESULTS

  Sixteen studies examined clinical diagnoses, four studies examined psychosocial problems and 11 studies examined cessation outcomes in co-occurring cannabis and tobacco users (several studies examined multiple clinical correlates). Relative to cannabis use only, co-occurring cannabis and tobacco use was associated with a greater likelihood of cannabis use disorders, more psychosocial problems and poorer cannabis cessation outcomes. Relative to tobacco use only, co-occurring use did not appear to be associated consistently with a greater likelihood of tobacco use disorders, more psychosocial problems or poorer tobacco cessation outcomes.

CONCLUSIONS

  Cannabis users who also smoke tobacco are more dependent on cannabis, have more psychosocial problems and have poorer cessation outcomes than those who use cannabis but not tobacco. The converse does not appear to be the case.

Joint trajectories of victimization and marijuana use and their health consequences among urban African American and Puerto Rican young men

We examined the joint trajectories of violent victimization and marijuana use from emerging adulthood to the early thirties and their health consequences in the early thirties among urban African American and Puerto Rican men. Data were collected from a community sample of young men (N = 340) when they were 19, 24, 29, and 32 years old. The joint trajectories of violent victimization and marijuana use were extracted using growth mixture modeling. Three distinct joint trajectory groups of violent victimization and marijuana use were identified: high violent victimization/consistently high marijuana use; low violent victimization/increasingly high marijuana use, and low violent victimization/low marijuana use. Group comparisons using regression analyses showed that men who had experienced high levels of violent victimization and were high frequency marijuana over time users experienced the most adverse psychological and physical health outcomes, including more health problems, psychological maladjustment, and substance use disorders.

Comorbid trajectories of tobacco and marijuana use as related to psychological outcomes

Heterogeneous classes of comorbid trajectories of tobacco and marijuana use were examined in order to determine how they are related to subsequent antisocial behavior, poor self-control, and internalizing behavior. Data are from a 4-wave longitudinal study of African American (n = 243) and Puerto Rican (n = 232) adolescents and adults in the community. Logistic regression analyses were employed to measure the association between the comorbid trajectories of tobacco and marijuana use and the psychological difficulty variables. The authors found 6 joint trajectory groups. The authors compared the non-or-experimental tobacco/marijuana use group with the other user groups in each of the psychological difficulty domains. The infrequent tobacco/late-onset marijuana use and chronic tobacco/marijuana use groups differed most strongly from the non-or-experimental tobacco/marijuana use group across the antisocial behavior, poor self-control, and internalizing problems domains. The chronic tobacco/maturing out marijuana use group also had significant associations in each of these domains. The infrequent tobacco/marijuana use and late-onset tobacco/infrequent marijuana use groups had no or weak associations with the psychological outcomes. Tobacco and marijuana cessation programs should identify and address comorbid use of tobacco and marijuana, and antisocial behavior, poor self-control, and internalizing problems, which are associated with histories of comorbid use of the 2 substances.

Maternal predictors of comorbid trajectories of cigarette smoking and marijuana use from early adolescence to adulthood

This is the first study to examine maternal predictors of comorbid trajectories of cigarette smoking and marijuana use from adolescence to adulthood. Participants (N=806) are part of an on-going longitudinal psychosocial study of mothers and their children. Mothers were administered structured interviews when participants were adolescents, and participants were interviewed at six time waves, from adolescence to adulthood. Mothers and participants independently reported on their relationships when participants were X¯ age 14.1 years. At each time wave, participants answered questions about their cigarette and marijuana use from the previous wave to the present. Latent growth mixture modeling determined the participants' membership in trajectory groups of comorbid smoking and marijuana use, from X¯ ages 14.1 to 36.6 years. Multivariate logistic regression was used to assess the association of maternal factors (when participants were adolescents) with participants' comorbid trajectory group membership. Findings showed that most maternal risk (e.g., mother-child conflict, maternal smoking) and protective (e.g., maternal affection) factors predicted participants' membership in trajectory groups of greater and lesser comorbid substance use, respectively. Clinical implications include the importance of addressing the mother-child relationship in prevention and treatment programs for comorbid cigarette smoking and marijuana use.

Addiction as a systems failure: focus on adolescence and smoking

OBJECTIVE

Scientific advances in the field of addiction have forever debunked the notion that addiction reflects a character flaw under voluntary control, demonstrating instead that it is a bona fide disease of the brain. The aim of this review is to go beyond this consensus understanding and explore the most current evidence regarding the vast number of genetic, developmental, and environmental factors whose complex interactions modulate addiction risk and trajectory.

METHOD

Focusing on childhood and adolescent smoking as a paradigm, we review the important risk factors for the development of addictions, starting at the level of genetics and closing with a focus on sociocultural and policy factors.

RESULTS

A critical review of the pertinent literature provides a detailed view of the cumulative power of risk and protection factors across different phenomenological levels to modulate the risk of undesirable outcomes, particularly for young people. The result represents a compelling argument for the need to engage in comprehensive, multilevel approaches to promoting health.

CONCLUSIONS

Today, the field of medicine understands more about disease than about health; however it need not be that way. The view of drug addiction as a systems failure should help refocus our general approach to developing dynamic models and early comprehensive interventions that optimize the ways in which we prevent and treat a complex, developmental disorder such as drug addiction.

Developmental trajectories of marijuana use from adolescence to adulthood: personal predictors

OBJECTIVE

To investigate the relationship between early adolescent personal characteristics and the developmental trajectories of marijuana use extending from early adolescence to adulthood.

DESIGN

This study used a longitudinal design. Data were obtained using structured questionnaires administered by trained interviewers.

SETTING

Interviews were conducted in the participants' homes in upstate New York.

PARTICIPANTS

Participants were drawn from a randomly selected cohort and were studied prospectively since 1975 (T1) at a mean age of 6 years. The follow-up data used for this study were collected at 6 time points when the participants were aged between 14 and 37 years in 1983 (T2), 1985-1986 (T3), 1992 (T4), 1997 (T5), 2002 (T6), and 2005-2006 (T7).

MAIN OUTCOME MEASURES

Developmental trajectories of marijuana use.

RESULTS

Semiparametric group-based modeling and logistic regression analyses were used to analyze the data. The following 5 distinct trajectories of marijuana use were identified: nonusers or experimenters, occasional users, quitters or decreasers, increasing users, and chronic users. Chronic users compared with other groups studied (nonusers or experimenters, occasional users, quitters or decreasers, and increasing users) reported low self-control, externalizing behavior, and an orientation to sensation seeking.

CONCLUSIONS

Personal attributes of low self-control, externalizing behavior, and an orientation to sensation seeking have long-term predictive power for distinct trajectories of marijuana use over time. The importance of these findings for prevention and treatment programs is discussed.