Identifying subtypes of dual alcohol and marijuana users: a methodological approach using cluster analysis

Predictors of substance use disorder treatment and mutual support group participation among Black women across the criminal legal spectrum: A latent class approach

BACKGROUND

The purpose of this study includes: 1) identifying classes of substance-related needs among Black women, and 2) examining the effect of substance-related need classes and culturally-relevant factors on Black women's use of substance use disorder (SUD) treatment and mutual support groups.

METHODS

As part of a longitudinal cohort study, Black women were recruited in prison nearing release, on probation, and in the community without involvement in the criminal legal system (CLS, n=565) and followed-up at 18-months. We conducted a baseline latent class analysis of substance-related needs among Black women. Logistic regression models adjusted for culturally-relevant factors to predict the use of treatment and frequency of mutual support group participation over 18-months among Black women who use drugs.

RESULTS

Four classes by level of needs were found: low, daily marijuana use, high mental health, and high comorbidity. During the 18-month follow-up, women characterized by the high comorbidity need class and with higher scores of religious well-being were more likely to frequently participate in mutual support groups. Non-CLS-involved women were less likely to engage with both treatment and mutual support groups than women from the prison sample at 18-months.

CONCLUSIONS

This study highlights four distinct classes of substance-related needs among Black women, highlighting the complex patterns of behavior and within-racial group differences among Black women. Black women with high comorbidity needs were more likely to participate in mutual support groups, but the latent classes did not predict SUD treatment indicating other non-medical and social contextual need factors may be at play.

Latent profile analysis of college students' alcohol and cannabis co-use patterns after recreational cannabis legalization

OBJECTIVE

Evidence is mixed on how young adults' cannabis and alcohol use and co-use patterns have changed following recreational cannabis legalization (RCL). Incorporating measures of frequency and intensity of use we examined changes in college students' use and co-use patterns following RCL.

METHOD

Four-year college students (n = 845,589) ages 18-24 years participated in the National College Health Assessment between 2008 and 2018, including students from 7 states that enacted RCL and 42 that did not. Latent profile analyses identified six patterns of use from four indicator variables tapping frequency of cannabis use and frequency and intensity of alcohol use: Abstainers, Light Alcohol Only, Heavy Alcohol Only, Predominantly Heavy Cannabis Use, Moderate Co-use, and Heavy Co-use.

RESULTS

Regression models that adjusted for time and person- and institution-level covariates indicated that students' exposure to RCL was associated with lower odds of being in the two alcohol-only use classes, higher odds of being in the Predominantly Heavy Cannabis Use, Heavy Co-Use and Abstainers classes, and was not significantly related to Moderate Co-Use class membership.

CONCLUSIONS

RCL was positively associated with patterns of frequent cannabis use and frequent and intense co-use but also with abstinence. Use of alcohol-only became less prevalent after RCL. Research on how RCL influences the prevalence of problematic patterns of substance use will inform and improve prevention efforts.

Simultaneous Cannabis and Alcohol Use among Medical Cannabis Patients

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

Alcohol & cannabinoid co-use: Implications for impaired fetal brain development following gestational exposure

Alcohol and marijuana are two of the most consumed psychoactive substances by pregnant people, and independently, both substances have been associated with lifelong impacts on fetal neurodevelopment. Importantly, individuals of child-bearing age are increasingly engaging in simultaneous alcohol and cannabinoid (SAC) use, which amplifies each drug's pharmacodynamic effects and increases craving for both substances. However, to date, investigations of prenatal polysubstance use are notably limited in both human and non-human populations. In this review paper, we will address what is currently known about combined exposure to these substances, both directly and prenatally, and identify shared prenatal targets from single-exposure paradigms that may highlight susceptible neurobiological mechanisms for future investigation and therapeutic intervention. Finally, we conclude this manuscript by discussing factors that we feel are essential in the consideration and experimental design of future preclinical SAC studies.

Patterns of Cannabis and Alcohol Co-Use: Substitution Versus Complementary Effects

PURPOSE

The purpose of this review is to discuss the literature regarding the concurrent use (co-use) of alcohol and cannabis and competing hypotheses as to whether cannabis acts as a substitute for (i.e., replacing the effects of alcohol, resulting in decreased use) or a complement to (i.e., used to enhance the effects of alcohol, resulting in increased use) alcohol. The impact of cannabis use on alcohol-related outcomes has received increased attention in the wake of ongoing legalization of cannabis for both medical and recreational purposes. Evidence for both hypotheses exists in the literature across a broad range of data collection methods and samples and is carefully reviewed here. In addition, various mechanisms by which cannabis may act as an alcohol substitute or complement are explored in depth with the goal of better understanding equivocal findings.

SEARCH METHODS

This review includes articles that were identified from a search for studies on alcohol and cannabis co-use, with a specific focus on studies exploring complementary versus substitution aspects of co-use. Search terms were included in Google Scholar, PsycINFO, MEDLINE, and Web of Science. Eligible studies were those that measured alcohol and cannabis co-use in human samples in laboratory, survey, or ecological momentary assessment studies, or that directly referenced substitution or complementary patterns of use.

SEARCH RESULTS

Search results returned 650 articles, with 95 meeting inclusion criteria.

DISCUSSION AND CONCLUSIONS

Results of this review reveal compelling evidence for both substitution and complementary effects, suggesting nuanced yet significant distinctions across different populations examined in these studies. Several mechanisms for the impact of cannabis use on alcohol-related outcomes are identified, including patterns and context of co-use, timing and order of use, cannabinoid formulation, pharmacokinetic interactions, and user characteristics (including diagnostic status), all of which may influence substitution versus complementary effects. This review will inform future research studies examining this topic in both clinical and community samples and aid in the development of treatment and prevention efforts targeting those populations most vulnerable to negative consequences of co-use. Finally, this review highlights the need for additional research in more diverse samples and the use of mixed-methods designs to examine both pharmacological and contextual influences on co-use.

Changes in alcohol use by cannabis use status among adolescents and young adults in the United States: Emerging evidence for both substitution and complementarity

BACKGROUND

The majority of adolescents and young adults (AYA) who use cannabis also use alcohol. Although cannabis use is increasing in the United States (US), it is not known whether the increase contributes to either increased co-use of alcohol and cannabis (e.g., complementarity) or replacement of alcohol with cannabis (e.g., substitution). The current study estimated the prevalence of alcohol use by cannabis use status among US AYA ages 12 to 25 in 2018 and trends in alcohol use by cannabis use status from 2002 to 2018.

METHODS

Data were drawn from the 2002 to 2018 National Survey on Drug Use and Health public use data files. The analytic sample included AYA ages 12 to 25 (2018 sample, n = 26,924; total combined sample 2002 to 2018, n = 576,053). Linear and logistic regression models were used to estimate past-month alcohol use, daily alcohol use, and average quantity of alcohol consumed among AYA with and without past-month cannabis use from 2002 to 2018.

RESULTS

In 2018, any alcohol use and daily alcohol use were significantly more common among AYA who used cannabis use than those who did not use cannabis. Overall, any alcohol use, daily alcohol use, and average drinks per day declined from 2002 to 2018 among AYA irrespective of recent cannabis use. However, the decline in any alcohol use, daily alcohol use, and average alcohol drinks per day was more rapid among AYA who used cannabis (daily and nondaily) than those who did not use cannabis. The rate of decline in average alcohol drinks per day was also higher among AYA with daily compared to nondaily cannabis use.

CONCLUSIONS

Even with declines in alcohol use over time, drinking is much more common among AYA who report cannabis than those without recent cannabis use, which is consistent with complementarity. Yet, because the decline in alcohol use has been more rapid among AYA who use cannabis, there is also evidence of substitution. Thus, the current data on alcohol and cannabis use are consistent with both complementarity and substitution. However, these relationships may change as cannabis legalization expands over time.

Drinking less on cannabis use days: The moderating role of UPPS-P impulsive personality traits

Objective: Several studies suggest that alcohol and cannabis co-users are heavier drinkers and experience more alcohol-related consequences. However, day-level associations between co-use and drinking levels are mixed. One reason may be that individual characteristics moderate the daily impact of using alcohol alone or in conjunction with cannabis. The theory would suggest that highly impulsive individuals may drink more on co-use days, yet this assertion remains untested. Therefore, the current study tested whether impulsivity moderated the effect of co-use on same-day drinking quantity within veterans, a high-risk sample for substance use and impulsivity. Method: In a longitudinal observational study, co-using veterans (N = 139) completed three semi-annual assessments reporting on their daily drinking quantity and cannabis use via Timeline Followback (Observations = 19,245) and impulsivity via the UPPS-P. Mixed effect modeling was used to test hypotheses that co-use (compared to alcohol-only) days would be associated with heavier drinking for those high (but not low) in positive and negative urgency. Results: Significant interactions were found for positive urgency (PU) and lack of perseverance (LP), such that individuals at mean and low levels of PU and LP drank less on co-use (compared to alcohol-only) days. There were no significant interactions for other UPPS-P impulsivity facets. Conclusion: Findings are consistent with a substitution/compensatory effect for individuals at mean and low levels of both UPPS-P facets, and may be a byproduct of frequent cannabis use in veterans. In contrast, findings suggest that co-use and alcohol-only days may be characterized by similarly high levels of drinking for highly impulsive individuals. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Between- and within-group effects of alcohol and cannabis co-use on AUD/CUD in the NSDUH 2002-2019

BACKGROUND

Alcohol and cannabis co-use is a between-group risk factor for heavier drinking and negative consequences, but only one study has tested links between co-use and AUD. In addition, few studies focus on risk profiles within co-users, despite heterogeneity in levels of co-use. The current study tested between-group (co-users vs. alcohol-/cannabis-only users) and within-group (patterns of co-use) risk profiles for AUD and CUD in a large, nationally representative sample.

METHODS

Data from the 2002-2019 National Study on Drug Use and Health (NSDUH) were used for analyses (N = 1,005,421). Analyses tested 1) whether co-users had greater odds of AUD/CUD than alcohol- and cannabis-only users, respectively, 2) whether there were latent profiles of co-use patterns within co-users, and 3) whether profile membership conferred within-group risk for AUD/CUD.

RESULTS

Co-users were at 3.38 greater odds of having an AUD, but co-use did not confer risk for CUD. Within co-users, five latent profiles emerged: weekly alcohol/cannabis use, weekly alcohol/monthly cannabis, weekly cannabis/occasional alcohol, weekly alcohol/occasional cannabis, and occasional use of both. Multiple comparisons suggested that, generally as frequency of each substance use increased, odds of both AUD and CUD became greater.

CONCLUSIONS

Primary alcohol users who also use cannabis are at risk for AUD, but the opposite effect was not observed in primary cannabis users. Higher frequency of each substance also conferred risk within co-users for both AUD and CUD. Findings add novel contributions that should be considered within both alcohol and cannabis use interventions. Future studies using prospective data are needed.

Co-use of Tobacco Products and Cannabis among Veterans: A Preliminary Investigation of Prevalence and Associations with Mental Health Outcomes

While tobacco product (such as combustible cigarettes and nicotine vaping products) and cannabis use rates remain high in the general United States (U.S.) population, veterans from the conflicts in Iraq and Afghanistan (i.e., OEF/OIF veterans) are at high risk of high rates of cannabis and tobacco use. Co-use of tobacco and cannabis (i.e., using both substances within a specified period of time or combining the drugs within the same device for use) is of growing prevalence in the U.S. However, little is understood about the prevalence rates of tobacco and cannabis co-use among U.S. veterans and its associations with mental health symptomatology. The current study conducted a preliminary analysis of co-use patterns of tobacco and cannabis and associated mental health outcomes among a sample of OEF/OIF veterans (N = 1,230). Results indicated high rates of lifetime and past 30-day use of both substances. Past 30-day co-users endorsed significantly higher levels of stress, PTSD, depression, and anxiety compared to singular product users. Results suggest that the addition of cannabis use in conjunction with tobacco use may be associated with greater mental health symptoms among veterans. Findings indicate veteran tobacco and cannabis co-users may benefit from mental health care to help mitigate poor mental health symptoms.

Impact of state-level cannabis legalization on poly use of alcohol and cannabis in the United States, 2004-2017

BACKGROUND

Cannabis policy has shifted toward legalization in many parts of the United States (US). While attention has been focused on whether legalization will lead to changes in cannabis use, it is conceivable that legalization will also affect use of substances that individuals frequently use with cannabis. This study assessed whether cannabis legalization impacted the prevalence of poly use of cannabis and alcohol from 2004 to 2017 and estimated the prevalence of cannabis and alcohol poly use in 2017.

METHODS

Public and restricted-use data from the US 2004-2017 National Survey on Drug Use and Health were analyzed. Data on past-month cannabis and alcohol use were assessed each year. Cannabis legalization was determined by the presence or absence of medical marijuana laws (MML) and recreational marijuana laws (RML) in each state. Difference-in-difference approach was used to estimate the association of MML and RML on cannabis and alcohol use overall and by sociodemographic subgroups (e.g., age, income, education).

RESULTS

Between 2004 and 2017, poly use of cannabis and alcohol increased while alcohol-only use decreased. MML were associated with increases in poly use only among adults over age 50 and among those with higher annual incomes and higher education, while RML were associated with increases in poly use broadly among adults across sociodemographic groups.

CONCLUSIONS

Legalization of cannabis was associated with increases in cannabis-alcohol poly use in the US. RML were associated with increases across demographics, while the impact of MML was more limited to certain sociodemographic groups.

Motives for Alcohol and Marijuana Use as Predictors of Use and Problem Use Among Young Adult College Students

This study examined (a) differences between alcohol-only users and alcohol-marijuana co-users and (b) motives for use in relation to alcohol and marijuana use and problem use. Spring 2016 data among 1,870 past 4-month alcohol users (63.6% female, 69.1% White) from seven Georgia colleges/universities were analyzed cross-sectionally and with regard to problem use measured 4 months later. Correlates of co-use (n = 345; vs. alcohol-only use, n = 1,525) included greater alcohol and marijuana use frequency, problem drinking and marijuana use, and alcohol use motives (p's < .05). Controlling for covariates, alcohol use frequency correlated with greater marijuana use frequency and Coping and Self-enhancement alcohol use motives, but lower Conformity alcohol use motives (p's < .001); greater Coping and Self-enhancement alcohol use motives (p's < .01) predicted problem alcohol use. Marijuana use frequency correlated with greater Coping and Expansion marijuana use motives (p's < .05); greater Expansion marijuana use motives (p = .005) predicted problem marijuana use. College-based substance use interventions should target Coping and Self-enhancement alcohol use motives and Expansion marijuana use motives.

Consequences of alcohol and marijuana use among college students: Prevalence rates and attributions to substance-specific versus simultaneous use

College students who use alcohol and marijuana often use them simultaneously, so that their effects overlap. The present study examined whether negative consequences experienced by simultaneous alcohol and marijuana (SAM) users vary from those experienced by individuals who use alcohol and marijuana concurrently but not simultaneously (CAM) or single-substance users. We considered 9 types of consequences: cognitive, blackout, vomiting, academic/occupational, social, self-care, physical dependence, risky behaviors, and driving under the influence (DUI). Further, we examined whether consequences experienced by SAM users are attributed to using alcohol, marijuana, or both simultaneously. The sample included past-year alcohol and marijuana users age 18-24 (N = 1,390; 62% female; 69% White; 12% Hispanic) recruited from 3 U.S. college campuses. SAM users experienced a greater overall number of consequences than CAM or alcohol-only users, even controlling for frequency and intensity of alcohol and marijuana use and potentially confounding psychosocial and sociodemographic factors. Experiencing specific consequences differed between simultaneous and concurrent users, but after adjusting for consumption and other covariates, only blackouts differed. In contrast, SAM users were more likely to experience each consequence than alcohol-only users, with strongest effects for DUI, blackouts, and cognitive consequences. Among SAM users, consequences were most likely to be attributed to alcohol and were rarely attributed to simultaneous use. Being a user of both alcohol and marijuana and using alcohol and marijuana together so that their effects overlap each contribute to risk, suggesting there is value in targeting the mechanisms underlying type of user as well as those underlying type of use. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Binge Drinking, Cannabis Co-Consumption and Academic Achievement in First Year University Students in Spain: Academic Adjustment as a Mediator

Little is known about how binge drinking or the combination of binge drinking and cannabis consumption affect academic achievement in students during the transition to university, or about the mechanisms that mediate this relationship. The purpose of this study was to evaluate the association between this pattern of alcohol/cannabis consumption and academic achievement, considering academic adjustment as a possible mediator. A total of 258 Spanish, first-year university students (145 females and 113 males), enrolled in undergraduate degree courses, were categorized into three groups on the basis of their patterns of alcohol/cannabis consumption: control, binge drinkers and co-consumers. The findings showed a significant effect of the combined binge drinking/cannabis consumption, but not of binge drinking alone, upon academic achievement and academic adjustment. Grade point average (GPA) and academic adjustment were lower in the co-consumers than in the other groups. Regarding the mediation effect, 34.33% of the impact of combined alcohol/cannabis use on GPA was mediated by academic adjustment. The combined consumption of alcohol and cannabis led to difficulties in adaptation to academic life, which in turn contributed to poorer performance at university. The implications of the findings are discussed.

Elevated Behavioral Economic Demand for Alcohol in Co-Users of Alcohol and Cannabis

OBJECTIVE

Co-use of cannabis and alcohol is associated with increased drinking and other negative consequences relative to use of alcohol alone. One potential explanation for these differences is overvaluation of alcohol (e.g., alcohol demand) among co-users, similar to established overvaluation of alcohol among tobacco and alcohol co-users. This study examined differences in alcohol demand between an alcohol and cannabis co-user group and an alcohol-only group.

METHOD

A large sample of adult drinkers (n = 1,643, 54% female) was recruited through an online crowdsourcing site (Amazon Mechanical Turk). Of the full sample, 476 participants reported weekly or greater cannabis use in the past 6 months (co-user group); 888 reported never using cannabis in the past 6 months (alcohol-only group). Assessments included a validated alcohol purchase task and self-report measures of alcohol and cannabis use.

RESULTS

Co-users reported significantly higher alcohol consumption across the elastic portion of the alcohol demand curve (i.e., $1.50-$9.00/drink). Analyses of covariance controlling for alcohol use and demographics revealed significantly higher breakpoint (p = .025) and Omax (p = .002) and significantly lower elasticity (p < .003) in the co-user group. Intensity and Pmax did not significantly differ between groups.

CONCLUSIONS

Co-users of cannabis and alcohol overvalue alcohol compared with individuals who drink alcohol but do not use cannabis. This study is generally consistent with prior studies on alcohol and tobacco co-users, providing converging evidence that polysubstance use is associated with overvaluation of alcohol. These findings have important implications for treatment and prevention, particularly in the context of changes in cannabis legalization.

Marijuana use is associated with alcohol use and consequences across the first 2 years of college

College entry is associated with marijuana initiation, and co-use of alcohol and marijuana is associated with problematic outcomes, including alcohol-related consequences. The present study explored if: (a) use of marijuana on a given day would be associated with greater alcohol use within the same day; (b) use of marijuana within a given week would be associated with increased alcohol-related consequences in that same week; and (c) the association between marijuana use and alcohol consumption and consequences varies across time or by precollege level of problematic alcohol use. Participants (N = 488 college student drinkers, 59% female) completed assessments of marijuana use, alcohol use, and alcohol consequences across 2 years. Analyses revealed: (a) daily marijuana use predicted greater number of daily drinks and estimated breath alcohol concentration; (b) weekly marijuana use predicted more weekly positive and negative alcohol consequences; (c) the effect of daily marijuana use on alcohol use strengthened over time, while the effect of weekly marijuana use on positive alcohol consequences reduced over time; and (d) precollege level of problematic alcohol use moderated the association between daily marijuana and alcohol use and weekly marijuana use and negative consequences. This study provides the first longitudinal evidence of the association between marijuana use and greater alcohol use and consequences in college students. Future research examining event-level measurement of alcohol and marijuana co-use is important for the prevention of alcohol-related consequences. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Daily Patterns of Marijuana and Alcohol Co-Use Among Individuals with Alcohol and Cannabis Use Disorders

BACKGROUND

The study aims were to examine daily associations between marijuana and alcohol use and the extent to which the association differs as a function of cannabis use disorder (CUD) and/or alcohol use disorder (AUD) diagnosis.

METHODS

Timeline Followback interview data was collected in a study of veterans (N = 127) recruited from a Veterans Affairs hospital who reported at least 1 day of co-use of marijuana and alcohol in the past 180 days (22,860 observations). Participants reported 40% marijuana use days, 28% drinking days, with 37% meeting DSM-5 criteria for CUD, 40% for AUD, and 15% for both. Use of marijuana on a given day was used to predict a 3-level gender-adjusted drinking variable (heavy: ≥5 (men)/4 (women) drinks; moderate: 1 to 4/3 drinks; or none: 0 drinks). A categorical 4-level variable (no diagnosis, AUD, CUD, or both) was tested as a moderator of the marijuana-alcohol relationship.

RESULTS

Multilevel modeling analyses demonstrated that participants were more likely to drink heavily compared to moderately (OR = 2.34) and moderately compared to not drinking (OR = 1.61) on marijuana use days relative to nonuse days. On marijuana use days, those with AUD and those with AUD + CUD were more likely to drink heavily (OR = 1.91; OR = 2.51, respectively), but those with CUD were less likely to drink heavily (OR = 0.32) compared to moderately, nonsignificant differences between any versus moderate drinking in interaction models.

CONCLUSIONS

Heavy drinking occurs on days when marijuana is also used. This association is particularly evident in individuals diagnosed with both AUD and CUD and AUDs alone but not in those with only CUDs. Findings suggest that alcohol interventions may need to specifically address marijuana use as a risk factor for heavy drinking and AUD.

Co-use of Alcohol and Cannabis: A Review

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of the existing literature on the relationship between the co-use of cannabis and alcohol including (1) epidemiology, comorbidity, and associated consequences of cannabis and alcohol use disorders; (2) preclinical and clinical laboratory studies examining behavioral pharmacology of cannabis and alcohol co-use; and (3) clinical outcomes related to co-use.

RECENT FINDINGS

Findings from the literature reviewed suggest that the co-use of alcohol and cannabis is associated with additive performance impairment effects, higher and more frequent consumption levels, increased social and behavioral consequences such as driving while impaired, and greater likelihood of the experiencing comorbid substance use and mental health disorders. Furthermore, co-use may be associated with worse clinical outcomes, yet there are few studies examining the development and evaluation of interventions on reducing the co-use of cannabis and alcohol.

SUMMARY

There is a need for more rigorous and longitudinal research studies on the co-use of cannabis and alcohol to glean a more complete understanding of the relationship between the two substances. Findings can be used to develop and refine intervention strategies to successfully reduce cannabis and alcohol co-use.

Simultaneous versus concurrent use of alcohol and cannabis in the National Alcohol Survey

BACKGROUND

Cannabis is the most commonly used drug among those who drink, yet no study has directly compared those who use cannabis and alcohol simultaneously versus concurrently (i.e., separately) in the adult general population. Here, we assess differences in demographics, alcohol-related social consequences, harms to self, and drunk driving across simultaneous, concurrent, and alcohol-only using groups.

METHODS

Secondary analyses of the 2005 and 2010 National Alcohol Survey (N = 8,626; 4,522 female, 4,104 male), a Computer Assisted Telephone Interview survey of individuals aged 18 and older from all 50 states and DC. Blacks and Hispanics are over-sampled. Data were collected using list-assisted Random Digit Dialing. Multinomial and multivariable logistic regressions were used for analyses.

RESULTS

The prevalence of simultaneous use was almost twice as high as concurrent use, implying that individuals who use both cannabis and alcohol tend to use them at the same time. Furthermore, simultaneous use was associated with increased frequency and quantity of alcohol use. Simultaneous use was also the most detrimental: compared to alcohol only, simultaneous use approximately doubled the odds of drunk driving, social consequences, and harms to self. The magnitudes of differences in problems remained when comparing drunk driving among simultaneous users to concurrent users.

CONCLUSIONS

The overall set of results is particularly important to bear in mind when studying and/or treating problems among alcohol/cannabis co-users because they demonstrate that in the general population, co-users are a heterogeneous group who experience different likelihoods of problems relative to co-use patterns.

Outcomes associated with adolescent marijuana and alcohol use among urban young adults: A prospective study

OBJECTIVE

This study identifies and compares outcomes in young adulthood associated with longitudinal patterns of alcohol and marijuana use during adolescence among urban youth.

METHOD

Data come from a cohort of 678 urban, predominantly Black children followed from ages 6-25 (1993-2012). Analyses are based on the 608 children who participated over time (53.6% male). Longitudinal patterning of alcohol and marijuana use were based on annual frequency reports from grades 8-12 and estimated through latent profile analysis.

RESULTS

We identified four classes of alcohol and marijuana use including Non-Use (47%), Moderate Alcohol Use (28%), Moderate Alcohol/Increasing Marijuana Use (12%) and High Dual Use (13%). A marijuana only class was not identified. Analyses show negative outcomes in adulthood associated with all three adolescent substance use classes. Compared to the non-use class, all use classes had statistically significantly higher rates of substance dependence. Those in the 'High Dual Use' class had the lowest rate of high school graduation. Comparing classes with similar alcohol but different marijuana patterns, the 'Moderate Alcohol/Increasing Marijuana Use' class had a statistically significant increased risk of having a criminal justice record and developing substance use dependence in adulthood.

CONCLUSION

Among urban youth, heterogeneous patterns of alcohol and marijuana use across adolescence are evident, and these patterns are associated with distinct outcomes in adulthood. These findings suggest a need for targeted education and intervention efforts to address the needs of youth using both marijuana and alcohol, as well as the importance of universal early preventive intervention efforts.

Alcohol use potentiates marijuana problem severity in young adult women

BACKGROUND

Most young adult women who smoke marijuana also drink alcohol. Marijuana-related problems are associated with marijuana use frequency. We hypothesized that increased alcohol use frequency potentiates the association between frequency of marijuana use and marijuana-related problem severity.

METHODS

We recruited women aged 18 to 24 who smoked marijuana at least monthly and were not treatment seeking. Marijuana and alcohol use were measured using the timeline follow-back method. Problems associated with marijuana use were assessed using the Marijuana Problems Scale.

FINDINGS

Participants (n = 332) averaged 20.5 ± 1.8 years of age, were 66.7% non-Hispanic White, and reported using marijuana on 51.5 ± 30.6 and alcohol on 18.9 ± 16.8 of the 90 previous days. Controlling for education, ethnicity, years of marijuana use, and other drug use, frequency of marijuana use (b = .22; p < .01) and frequency of alcohol use (b = 0.13; p < .05) had significant, positive effects on marijuana problem severity. In a separate multivariate model, the linear by linear interaction of marijuana by alcohol use frequency was significant (b = 0.18; p < .01), consistent with the hypothesis.

CONCLUSIONS

Concurrent alcohol use impacts the experience of negative consequences from marijuana use in a community sample of young women. Discussions of marijuana use in young adults should consider the possible potentiating effects of alcohol use.