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

Inclusion of Cannabis Users in Alcohol Research Samples: Screening In, Screening Out, and Implications

BACKGROUND

Alcohol and cannabis are frequently co-used, as 20-50% of those who drink alcohol report co-using cannabis. This study is based on the argument that alcohol researchers should enroll cannabis users in human laboratory studies of alcohol use disorder (AUD) to strengthen generalizability. This study examines how heavy drinking cannabis users differ from non-cannabis using heavy drinkers.

METHODS

In a community sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users were identified through: (a) self-reported cannabis use in the past 6 months and (b) positive urine toxicology test for tetrahydrocannabinol (THC). Cannabis users, identified as described previously, were compared with non-cannabis users on demographic and clinical characteristics.

RESULTS

Those who endorsed cannabis use in the past 6 months reported more binge drinking days. Participants who tested positive for THC had higher Alcohol Use Disorder Identification Test scores and more binge drinking days. Younger age and being a tobacco smoker were associated with an increased likelihood of cannabis use in the past 6 months, whereas male gender and being a tobacco use were associated with a greater likelihood of testing positive for THC. Individuals with cannabis use disorder (CUD) endorsed more depression and anxiety and had higher AUD symptom counts than cannabis users without CUD.

CONCLUSIONS

The inclusion of cannabis users in AUD samples allows for increased clinical severity. Excluding cannabis users from AUD studies may limit representativeness and expend unnecessary study resources. Lastly, tobacco use may explain a large portion of the effects of cannabis use on sample characteristics.

SHORT SUMMARY

Alcohol and cannabis are frequently co-used substances. In a sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users reported higher alcohol use and higher likelihood of tobacco use than non-cannabis users. Including cannabis users in alcohol research studies will improve representativeness and likely increase clinical severity.

A Systematic Review of the Effects of Perinatal Alcohol Exposure and Perinatal Marijuana Exposure on Adult Neurogenesis in the Dentate Gyrus

BACKGROUND

Marijuana and alcohol are both substances that, when used during pregnancy, may have profound effects on the developing fetus. There is evidence to suggest that both drugs have the capacity to affect working memory, one function of the hippocampal formation; however, there is a paucity of data on how perinatal exposure to alcohol or cannabis impacts the process of adult neurogenesis.

METHODS

This systematic review examines immunohistochemical data from adult rat and mouse models that assess perinatal alcohol or perinatal marijuana exposure. A comprehensive list of search terms was designed and used to search 3 separate databases. All results were imported to Mendeley and screened by 2 authors. Consensus was reached on a set of final papers that met the inclusion criteria, and their results were summarized.

RESULTS

Twelve papers were identified as relevant, 10 of which pertained to the effects of perinatal alcohol on the adult hippocampus, and 2 pertained to the effects of perinatal marijuana on the adult hippocampus. Cellular proliferation in the dentate gyrus was not affected in adult rats and mice exposed to alcohol perinatally. In general, perinatal alcohol exposure did not have a significant and reliable effect on the maturation and survival of adult born granule neurons in the dentate gyrus. In contrast, interneuron numbers appear to be reduced in the dentate gyrus of adult rats and mice exposed perinatally to alcohol. Perinatal marijuana exposure was also found to reduce inhibitory interneuron numbers in the dentate gyrus.

CONCLUSIONS

Perinatal alcohol exposure and perinatal marijuana exposure both act on inhibitory interneurons in the hippocampal formation of adult rats. These findings suggest simultaneous perinatal alcohol and marijuana exposure (SAM) may have a dramatic impact on inhibitory processes in the dentate gyrus.

Cross-fading motives for simultaneous alcohol and marijuana use: Associations with young adults' use and consequences across days

BACKGROUND

Many young adults engage in simultaneous alcohol and marijuana (SAM) use so that their effects overlap. Little is known about motivations for dual substance use and associations with use and consequences. This study examined daily-level associations between cross-fading motives and levels of alcohol and marijuana use and consequences.

METHODS

Young adults who reported SAM use in the month prior were surveyed in two 14-day bursts. Data included 1049 SAM use days from 281 young adults (age 18-25; M age = 21.80, SD = 2.16; 50 % women). Multilevel models assessed between- and within-person effects of cross-fading motives (i.e., to enhance the effects of marijuana and/or alcohol use by using them simultaneously) on alcohol and marijuana use and consequences, after adjusting for general enhancement, social, coping, and conformity motives and the amount of alcohol and marijuana used that day.

RESULTS

On 76 % of SAM use days, participants endorsed cross-fading motives (i.e., to enhance the effect of alcohol or marijuana or to get drunk and high at the same time). Having stronger cross-fading motives was associated with greater alcohol use, perceived intoxication, and positive alcohol consequences at the between- and within-person levels. In addition, between-person, individuals who reported stronger cross-fading motives on average reported more negative alcohol consequences and positive marijuana consequences on average. Cross-fading motives on a given day were not associated with marijuana use or marijuana consequences that day.

CONCLUSIONS

Cross-fading motives were common and varied from day to day. Understanding the motivational context for dual substance use may support future interventions for cross-fading.

Does Cannabis Use Predict More Severe Types of Alcohol Consequences? Longitudinal Associations in a 3-Year Study of College Students

BACKGROUND

Prior research shows that negative drinking outcomes among young adults may be exacerbated by cannabis use. However, to date, there have been few longitudinal studies of associations between cannabis use and negative alcohol-related consequences. This study examined longitudinal within-person associations between cannabis use and several domains of negative alcohol consequences among young adults and explored the moderating role of sex.

METHOD

We analyzed data from N = 997 students assessed 4 times per year over the first 3 years of university. At each time point, participants completed measures of past-month cannabis use frequency, typical weekly number of drinks, and 8 domains of negative alcohol consequences. Longitudinal associations were examined in multilevel models.

RESULTS

Within-person changes in frequency of cannabis use were not uniquely associated with changes in total alcohol consequences aggregated across several alcohol consequence domains. However, when examining alcohol consequence domains separately, within-person increases in cannabis use frequency were specifically associated with increases in some (but not all) of the more severe types of alcohol consequences, including risky behaviors, poor self-care, and alcohol dependence symptoms. No support was observed for the moderating role of sex in the longitudinal within-person associations between cannabis use and alcohol consequence domains.

CONCLUSIONS

Findings suggest that within-person changes in cannabis use frequency among young adults are associated with corresponding changes in some domains of alcohol consequences (but not others) when examined over the course of several years. Results may inform targeted harm reduction interventions for young adult drinkers who use cannabis, although future research is needed to clarify the mechanisms of the observed associations.

Daily Motives for Alcohol and Marijuana Use as Predictors of Simultaneous Use Among Young Adults

OBJECTIVE

Research on substance use motives typically examines each substance separately. However, simultaneous alcohol and marijuana (SAM) use-that is, using alcohol and marijuana at the same time so that their effects overlap-is common among young adults. This study examines day-to-day fluctuations in motives for using alcohol and/ or marijuana among young adult substance users as predictors of alcohol, marijuana, and SAM use across days.

METHOD

Data were from a community sample of young adults who reported SAM use in the past month (analytic sample: N = 399, mean [SD] age = 21.63 [2.17]; 50.9% women). Participants reported alcohol, marijuana, and SAM use, and also motives "for alcohol and/or marijuana use" for 14 consecutive days.

RESULTS

Multilevel models showed that elevated enhancement motives were associated with heavy episodic drinking, drinking more, and more hours high from marijuana. Elevated social motives were associated with heavy episodic drinking and drinking more, and also with fewer hours high. Elevated conformity motives were associated with drinking more. SAM use was more likely: on alcohol days and on marijuana days with elevated enhancement and conformity motives, on alcohol days with elevated coping motives, and on marijuana days with elevated social motives.

CONCLUSIONS

SAM use on a given day was primarily associated with enhancement and conformity motives. Social motives were more strongly linked to alcohol use, and to some extent coping motives were linked to marijuana use in this young adult sample. Further examination of situation-specific motives and contexts of use is needed to inform development of real-time interventions for SAM use and consequences.

Patterns and correlates of cannabis use by cumulative lifetime violence severity as target and/or perpetrator in a community sample of eastern Canadian men

Background

Recent Canadian legalization of cannabis for non-medical use underscores the need to understand patterns and correlates of cannabis use among men who may be more likely than women to become problematic cannabis users. Evidence supporting an association between substance use and violence is accumulating. Current knowledge of relationships among patterns of cannabis use, violence, gender and health is limited by dichotomous measurement of cannabis use and a focus on individual types of violence rather than lifetime cumulative violence.

Methods

We collected online survey data between April 2016 and Septermber 2017 from a community convenience sample of 589 Eastern Canadian men ages 19 to 65 years and explored how socio-demographic characteristics, gender, and health varied by past-year patterns of cannabis use (i.e., daily, sometimes, never) in the total sample and by higher and lower cumulative lifetime violence severity (CLVS) measured by a 64-item CLVS scale score (1 to 4).

Results

Overall prevalence of cannabis use was 46.6% and differed significantly between lower (38.1%) and higher (55.3%) CLVS groups (χ² (1) = 17.42, p = .000). Daily cannabis use was more likely in the higher (25.1%) than the lower group (11.9%, χ² (2) = 31.53, p < .001). In the total sample, daily use was significantly associated with being single, less education, lower income, some gender norms, health problems, and use of other substances. Significant associations were found for sometimes cannabis use with age group 19 to 24 years, being single, some gender norms, and hazardous and binge drinking. Never use was associated with being married, more education, higher income, being older, not using other substances, and not having mental health problems. Associations between cannabis use patterns and many variables were found in both CLVS groups but effect sizes were frequently larger in the higher group.

Conclusions

These results add substantively to knowledge of relationships among lifetime cumulative violence, patterns of cannabis use, gender, socio-demographic indicators and health problems and may inform theoretical models for future testing. Additionally, findings provide critical information for the design of health promotion strategies targeted towards those most at risk in the current climate of cannabis legalization.

Simultaneous Alcohol and Marijuana Use: A Brief Measure of Motives

OBJECTIVE

Increasing numbers of substance users report simultaneous alcohol and marijuana (SAM) use such that their effects overlap. More research is needed to understand what motivates this behavior, especially to inform interventions that address SAM use. A 26-item measure of SAM motives was designed and tested in previous research. The purpose of the current study was to validate that measure and create a briefer version of it.

METHOD

Using two waves of data from a multi-site sample of college students (n = 1,014), exploratory and confirmatory factor analyses were conducted to develop a brief 11-item SAM Motives Measure (B-SMM). Negative binomial regression analyses were conducted to assess the reliability and validity of both the original and brief measures.

RESULTS

The brief measure contains four subscales (conformity, positive effects, calm/coping, and social) that match the empirically supported motivational model of substance use. Internal consistency of the subscales ranged from .77 to .87. Most subscales significantly predicted frequency and consequences of SAM use both concurrently and prospectively.

CONCLUSIONS

The psychometrically sound measure developed in this study facilitates the examination of SAM motives in clinical settings with time-constrained patient contact and can be valuable for research involving frequent and repeated measures of substance use behaviors.

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).

Simultaneous Alcohol and Marijuana Use: A Brief Measure of Motives

OBJECTIVE

Increasing numbers of substance users report simultaneous alcohol and marijuana (SAM) use such that their effects overlap. More research is needed to understand what motivates this behavior, especially to inform interventions that address SAM use. A 26-item measure of SAM motives was designed and tested in previous research. The purpose of the current study was to validate that measure and create a briefer version of it.

METHOD

Using two waves of data from a multi-site sample of college students (n = 1,014), exploratory and confirmatory factor analyses were conducted to develop a brief 11-item SAM Motives Measure (B-SMM). Negative binomial regression analyses were conducted to assess the reliability and validity of both the original and brief measures.

RESULTS

The brief measure contains four subscales (conformity, positive effects, calm/coping, and social) that match the empirically supported motivational model of substance use. Internal consistency of the subscales ranged from .77 to .87. Most subscales significantly predicted frequency and consequences of SAM use both concurrently and prospectively.

CONCLUSIONS

The psychometrically sound measure developed in this study facilitates the examination of SAM motives in clinical settings with time-constrained patient contact and can be valuable for research involving frequent and repeated measures of substance use behaviors.

Binge and Cannabis Co-Use Episodes in Relation to White Matter Integrity in Emerging Adults

Background: Growing evidence suggests that cannabis and alcohol (and especially binge alcohol drinking) use independently alters neural structure and functioning, particularly during sensitive developmental time periods (e.g., emerging adulthood). However, few studies have investigated the effects of same-day use of these two substances. Here, white matter (WM) integrity was investigated in relation to binge alcohol drinking, cannabis, and same-day binge and cannabis co-use in adolescents and emerging adults. Methods: FreeSurfer's TRACULA was used to assess WM in emerging adults (n=75; 16-26 years old). Timeline Followback calculated past month cannabis use, binge episodes, and same-day cannabis and binge drinking co-use. Multiple regressions investigated WM by past month cannabis, binge, and co-use. Results: Results revealed co-use episodes were related to lower fractional anisotropy (FA), an overall measure of neuronal integrity, in three tracts (left inferior longitudinal fasciculus [ILF], p=0.02; right anterior thalamic radiation [ATR], p=0.01; and left cingulum cingulate gyrus [CCG], p=0.01); and lower axial diffusivity in left ILF (p=0.03). Cannabis use was significantly related to greater FA in left ILF (p=0.005), left ATR (p=0.02), right ATR (p=0.05), left CCG (p=0.006), right CCG (p=0.03), and right superior longitudinal fasciculus parietal (p=0.03). Binge episodes related to greater FA in right ATR (p=0.03). Conclusions: These findings suggest that co-use was associated with lower WM integrity across frontolimbic tracts. In addition, greater FA was related to greater cannabis use across several tracts and binge alcohol use in one tract. Co-users also appeared to be more severe substance users. Future research should investigate the potential independent and interactive effects of these substances on pre-clinical and clinical levels.

A Daily Study Comparing Alcohol-Related Positive and Negative Consequences for Days With Only Alcohol Use Versus Days With Simultaneous Alcohol and Marijuana Use in a Community Sample of Young Adults

BACKGROUND

Alcohol and marijuana are psychoactive substances commonly used by young adults and are independently associated with numerous acute and long-term consequences. Many young adults engage in simultaneous alcohol and marijuana (SAM) use to cross-fade (i.e., to enhance the effects of intoxication), although the extent to which alcohol use and alcohol-related consequences increase on SAM occasions compared to alcohol-only occasions is unclear. This study examines daily data among a sample of SAM users comparing SAM days to other days when young adults only used alcohol.

METHODS

A sample of 409 young adults (age 18 to 25; M_age  = 21.6, SD = 2.2; 50.9% women) who reported SAM use in the past month completed 2 bursts of 14 days of daily surveys (28 days in total) assessing alcohol use, alcohol-related consequences, and SAM use.

RESULTS

Multilevel models based on alcohol-only and SAM days (n = 3,016 days; 391 individuals) indicated young adults drank more alcohol on SAM days compared to alcohol-only days (with no marijuana use). Similarly, days with SAM use were associated with more alcohol-related positive and negative consequences. The daily association between SAM use and positive consequences was statistically significant, after accounting for the amount of alcohol consumed; in contrast, the association between SAM use and negative consequences was diminished and nonsignificant.

CONCLUSIONS

Among young adult SAM users, days with SAM use were associated with more alcohol use and positive consequences compared to days they only drank alcohol. Further examination of the motivational context for engaging in SAM use, as well as potential physiological interactions between alcohol and marijuana use on alcohol's effects, is warranted. Alcohol interventions might benefit from addressing increased alcohol use and alcohol-related consequences as risks associated with SAM use.

Potential influence of socioeconomic status on genetic correlations between alcohol consumption measures and mental health

BACKGROUND

Frequency and quantity of alcohol consumption are metrics commonly used to measure alcohol consumption behaviors. Epidemiological studies indicate that these alcohol consumption measures are differentially associated with (mental) health outcomes and socioeconomic status (SES). The current study aims to elucidate to what extent genetic risk factors are shared between frequency and quantity of alcohol consumption, and how these alcohol consumption measures are genetically associated with four broad phenotypic categories: (i) SES; (ii) substance use disorders; (iii) other psychiatric disorders; and (iv) psychological/personality traits.

METHODS

Genome-Wide Association analyses were conducted to test genetic associations with alcohol consumption frequency (N = 438 308) and alcohol consumption quantity (N = 307 098 regular alcohol drinkers) within UK Biobank. For the other phenotypes, we used genome-wide association studies summary statistics. Genetic correlations (rg) between the alcohol measures and other phenotypes were estimated using LD score regression.

RESULTS

We found a substantial genetic correlation between the frequency and quantity of alcohol consumption (rg = 0.52). Nevertheless, both measures consistently showed opposite genetic correlations with SES traits, and many substance use, psychiatric, and psychological/personality traits. High alcohol consumption frequency was genetically associated with high SES and low risk of substance use disorders and other psychiatric disorders, whereas the opposite applies for high alcohol consumption quantity.

CONCLUSIONS

Although the frequency and quantity of alcohol consumption show substantial genetic overlap, they consistently show opposite patterns of genetic associations with SES-related phenotypes. Future studies should carefully consider the potential influence of SES on the shared genetic etiology between alcohol and adverse (mental) health outcomes.

Simultaneous alcohol and marijuana use in daily life: Implications for level of use, subjective intoxication, and positive and negative consequences

Simultaneous alcohol and marijuana (SAM) use is prevalent among young adult drinkers and associated with increased risk for harms. Less understood about SAM use is whether increased risk is incurred on SAM use occasions relative to occasions in which individuals used only 1 substance. From a sample of young adult SAM users, we compared occasions in which individuals simultaneously used alcohol and marijuana so that the effects overlapped ("SAM days"), occasions involving only alcohol ("alcohol days"), and occasions involving only marijuana ("marijuana days") on level of use, level of subjective intoxication, and negative and positive consequences. Eligible participants (N = 154; 57.8% female, 72.7% non-Hispanic/Latinx White) were 18-25 years old, reported past-month SAM use, and reported past 2-week binge drinking. Participants completed up to 14 daily assessments on their substance use behavior. Multilevel models indicated that, relative to alcohol days, SAM days had more negative consequences. SAM and alcohol days were not statistically different on level of use, level of subjective alcohol intoxication, or positive consequences. Relative to marijuana days, SAM days had more negative consequences and more positive consequences. Level of use (number of hits) and level of marijuana intoxication were not statistically different. In addition to SAM users being a more at-risk group, SAM occasions are associated with greater risk within this vulnerable population. Fine-grained ecological momentary assessments are needed to better understand perceptions and behavior throughout a SAM use episode. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

"Buzzwords": Crowd-sourcing and quantifying U.S. young adult terminology for subjective effects of alcohol and marijuana use

Prevalence of heavy alcohol use remain high, and daily marijuana use is at an all-time high in young adults. As perceptions of drug effects may guide risky decision making, understanding subjective feelings for alcohol and marijuana use is critical. Existing laboratory-based and diary metrics (0-100 rating of "how drunk/high do you feel?") may be problematic in differentiating levels of subjective effects. Measures incorporating contemporary language may better capture subjective feelings in experimental and ambulatory assessment designs. We developed 2 sliding scales based on crowd-sourced and rank-ordered feelings of subjective alcohol and marijuana effects. Two U.S. young adult (18-25 years) samples were drawn from Amazon's Mechanical Turk (MTurk). In the first study, 323 (53.6% women, 68.4% White, M age = 23.0 years) alcohol and marijuana users provided words to describe subjective effects from alcohol use and from marijuana use. In a second study, 289 (46.4% female, 66.4% White, M age = 23.0 years) users rank-ordered the most common terms to correspond with subjective levels. The sliding scale for alcohol effects resulted in 4 anchors ranging from 0 to 100: slightly buzzed, tipsy/"happy," drunk, and wasted. The sliding scale for marijuana effects also had 4 anchors: relaxed, calm/chill, high, and stoned/baked. By incorporating broader and more contemporary subjective effects language, our metrics may better capture variability in young adults' perceived subjective effects from alcohol and marijuana use. Future work could build upon these findings by pairing sliding scales with measures of actual intoxication to understand within- and between-person covariation in subjective effects, actual impairment, and consequences. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Harmful drinking, tobacco, and marijuana use in the 2000-2015 National Alcohol Surveys: Examining differential trends by sexual identity

BACKGROUND

Population-based surveys document disparities in substance use among sexual minorities compared to heterosexuals, but few studies examine changes over time. This study compared changes in harmful drinking (including alcohol use disorders and high-intensity drinking), tobacco use, marijuana use, and simultaneous marijuana and alcohol co-use between heterosexual and sexual minority adults over a 15-year period. Methods: Gender-stratified logistic regression analyses using 4 waves of cross-sectional data from the National Alcohol Survey (2000, 2005, 2010, and 2015) were conducted to test overall trends over time and differences by sexual identity, as well as the interaction between survey year and sexual identity. Results: Among women, significant effects for sexual identity were present in all models, reflecting greater odds of use among sexual minorities across waves. Among men, significant effects for sexual identity were found for high-intensity drinking (reflecting less use among sexual minorities) as well as marijuana use and marijuana and alcohol co-use (reflecting more use among sexual minorities). For women and men, tobacco use generally decreased and both marijuana use and simultaneous marijuana and alcohol co-use increased during the study period. Although trends were largely driven by heterosexual respondents, only one instance of an interactive effect was found; reports of harmful drinking were generally stable over time among heterosexual women, but higher and more variable over time among sexual minority women. Conclusions: Findings highlight that differences in patterns of substance use by sexual identity persist and underscore the need for screening, prevention, and intervention, particularly for sexual minority women.

Simultaneous detection of salivary Δ9-tetrahydrocannabinol and alcohol using a Wearable Electrochemical Ring Sensor

Driving under the influence of cannabis and alcohol represents a major safety concern due to the synergistic or additive effect of these substances of abuse. Hence, rapid road-site testing of these substances is highly desired to reduce risks of fatal accidents. Here we describe a wearable electrochemical sensing device for the simultaneous direct, decentralized, detection of salivary THC and alcohol. The new ring-based sensing platform contains a voltammetric THC sensor and an amperometric alcohol biosensor on the ring cap, along with the wireless electronics embedded within the ring case. Rapid replacement of the disposable sensing-electrode ring cap following each saliva assay is accomplished by aligning spring-loaded pins, mounted on the electronic board (PCB), with the current collectors of the sensing electrodes. The printed dual-analyte sensor ring cover is based on a MWCNT/carbon electrode for the THC detection along with a Prussian-blue transducer, coated with alcohol oxidase/chitosan reagent layer, for the biosensing of alcohol. THC and alcohol can thus be detected simultaneously in the same diluted saliva sample within 3 min, with no cross talk and no interferences from the saliva matrix. The new wearable ring sensor platform should enable law enforcement personnel to screen drivers in a single traffic stop and offers considerable promise for addressing growing concerns of drug-impaired driving.

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.

Exploring Cannabis and Alcohol Co-Use in Adolescents: A Narrative Review of the Evidence

Objective: Amidst the evolving policy surrounding cannabis legalization in the United States, cannabis use is becoming increasingly prevalent as perceptions of harm decrease, particularly among adolescents. Cannabis and alcohol are commonly used by adolescents and are often used together. However, developmental research has historically taken a "single substance" approach to examine the association of substance use and adolescent brain and behavior rather than examining co-(or poly-substance) use of multiple substances, such as cannabis and alcohol. Thus, the acute effects of cannabis and alcohol, and the impact of co-use of cannabis and alcohol on the adolescent brain, cognitive function and subsequent psychosocial outcomes remains understudied. This narrative review aims to examine the effects of cannabis and alcohol on adolescents across a number of behavioral and neurobiological outcomes. Methods: The PubMed and Google Scholar databases were searched for the last 10 years to identify articles reporting on acute effects of cannabis and alcohol administration, and the effects of cannabis and alcohol on neuropsychological, neurodevelopmental, neural (e.g., structural and functional neuroimaging), and psychosocial outcomes in adolescents. When adolescent data were not available, adult studies were included as support for potential areas of future direction in adolescent work. Results: Current studies of the impact of cannabis and alcohol on adolescent brain and behavior have yielded a complicated pattern. Some suggest that the use of cannabis in addition to alcohol during adolescence may have a "protective" effect, yielding neuropsychological and structural brain outcomes that are better than those for adolescents who use only alcohol. However, other adolescent studies suggest that cannabis and alcohol co-use is associated with negative health and social outcomes such as poorer academic performance and impaired driving. Conclusion: Variation in study methodologies, policy-level limitations and our limited understanding of the developmental neurobiological effects of cannabis preclude the straightforward interpretation of the existing data on adolescent cannabis and alcohol use. Further research on this topic is requisite to inform the development of effective intervention and prevention programs for adolescent substance users, which hinge on a more comprehensive understanding of how cannabis-and its intersection with alcohol-impacts the developing brain and behavior.

Interaction of Cannabis Use and Aging: From Molecule to Mind

Given the aging Baby Boomer generation, changes in cannabis legislation, and the growing acknowledgment of cannabis for its therapeutic potential, it is predicted that cannabis use in the older population will escalate. It is, therefore, important to determine the interaction between the effects of cannabis and aging. The aim of this report is to describe the link between cannabis use and the aging brain. Our review of the literature found few and inconsistent empirical studies that directly address the impact of cannabis use on the aging brain. However, research focused on long-term cannabis use points toward cumulative effects on multimodal systems in the brain that are similarly affected during aging. Specifically, the effects of cannabis and aging converge on overlapping networks in the endocannabinoid, opioid, and dopamine systems that may affect functional decline particularly in the hippocampus and prefrontal cortex, which are critical areas for memory and executive functioning. To conclude, despite the limited current knowledge on the potential interactive effects between cannabis and aging, evidence from the literature suggests that cannabis and aging effects are concurrently present across several neurotransmitter systems. There is a great need for future research to directly test the interactions between cannabis and aging.

Prevalence and Correlates of Concurrent and Simultaneous Cannabis and Cigarette Use among Past-Year Cannabis-Using US College Students

Background: Cannabis and tobacco use are significant public health concerns among young adults, with concurrent (in the same time period) and simultaneous (at the same time so the effects overlap) use of both substances on the rise. Few studies have examined these behaviors among college students. Objective: We examined the prevalence of concurrent and simultaneous cannabis and cigarette (combustible or electronic) use among a sample of college students and characterized the psychosocial predictors of concurrent and simultaneous use compared to using cannabis alone. Methods: Data on past-3 months cannabis and cigarette use were collected on 1352 college students who were past-year cannabis and alcohol users yielding four groups: cannabis-only users (n = 686), concurrent cannabis and cigarette users (CCAC; n = 235), simultaneous cannabis and cigarette users (SCAC; n = 293), and non-recent users of either substance (n = 138). Multinomial logistic regression analyses were utilized to predict group membership. Results: Relative to the cannabis-only group, White, compared to Non-White students, males, compared to females, frequent, compared to infrequent, alcohol users, including those who used alcohol simultaneously with cigarettes, and illicit drug users were more likely to belong to the CCAC or SCAC group. Conclusions: Findings suggest the need for unique intervention efforts to prevent onset or reduce co-use among male and White students as well as illicit drug users and frequent alcohol users.

Investigating Relationships Between Alcohol and Cannabis Use in an Online Survey of Cannabis Users: A Focus on Cannabinoid Content and Cannabis for Medical Purposes

Cannabis is commonly used among people who drink alcohol, but findings are mixed regarding the direction of this relationship. The type of cannabis used [high-cannabidiol (CBD) vs. high-delta-9tetrahydrocannabinol (THC)] and motives for use (i.e., whether cannabis is used to treat a medical condition) may influence the relationship between cannabis and drinking. Specifically, CBD has shown preclinical promise in reducing alcohol consumption, and medical cannabis users report using cannabis to reduce drinking. This study leverages survey data from cannabis users who drink alcohol (N = 533). Respondents were categorized as using cannabis to treat (CTT) a medical condition or as individuals whose cannabis use is not intended to treat (NCTT) a medical condition and grouped based on the THC/CBD ratio of the flower or edible cannabis they typically use (e.g., "High-THC/CBD," "Medium-THC/CBD" and "Low-THC/CBD"). The CTT group (n = 412) reported drinking significantly less frequently than the NCTT group (n = 121). Cannabinoid content of flower cannabis was associated with alcohol consumed on cannabis-use days, such that individuals in the High-THC/CBD group drink more on cannabis-use days compared to the Medium-THC/CBD group. Cannabinoid content of edible cannabis was associated with drinks per drinking occasion, such that the High-THC/CBD group consumed the most drinks and the Low-THC/CBD group consumed the fewest. For both edible and flower groupings, higher-THC/CBD cannabis was associated with more frequent co-use than lower-THC/CBD cannabis. Results suggest that whether someone uses cannabis to treat a medical condition may impact their drinking frequency, and the cannabinoid content in flower and edible cannabis impacts alcohol consumption.

Cannabis Use among Dual Electronic and Combustible Cigarette Smokers: Relations with Pain and Hazardous Drinking

Background: E-cigarette use is on the rise and many adult e-cigarette users also smoke combustible cigarettes. Past work suggests that dual use (i.e. use of both electronic and combustible cigarettes) is associated with greater rates of cannabis use, yet little is known about the nature of cannabis use among dual users. Objectives: The current study examined 414 adult dual users (48.3% female, M_age = 35.1 years), half of whom endorsed current (past month) cannabis use. Results: Results indicated that cannabis users reported more severe pain, greater pain interference, and more hazardous drinking. In addition, cannabis use was robustly related to hazardous drinking after statistically controlling for demographic and pain-related variables. Cannabis use was also associated with hazardous drinking indirectly via pain interference at greater levels of pain severity. Conclusions/Importance: These results highlight several clinical correlates of cannabis use among adult dual users, and also suggest that pain may play an important role in hazardous drinking among these individuals.

Brain activation to cannabis- and alcohol-related words in alcohol use disorder

Cannabis abuse commonly co-occurs with alcohol use disorder (AUD). With increased acceptance and accessibility to cannabis in the US, it is imperative to understand the psychological and neural mechanisms of concurrent alcohol and cannabis use. We hypothesized that neural alcohol-cue conditioning may extent to other drug-related stimuli, such as cannabis, and underwrite the loss of control over reward-driven behavior. Task-activated fMRI examined the neural correlates of alcohol- and cannabis-related word cues in 21 abstinent AUD and 18 control subjects. Relative to controls, AUD showed behavioral attentional biases and frontal hypoactivation to both alcohol- and cannabis-related words. This cue-elicited prefrontal hypoactivation was related to higher lifetime alcohol consumption (pcorrected < 0.02) and modulated by past cannabis use histories (p ≦ 0.001). In particular, frontal hypoactivation to both alcohol and cannabis cues was pronounced in AUD without prior cannabis exposure. Overall, frontal control mechanisms in abstinent AUD were not sufficiently engaged to override automatic alcohol and cannabis-related intrusions, enhancing the risk for relapse and potentially for alcohol and cannabis co-use with the increased social acceptance and accessibility in the US.

Identifying subtypes of cannabis users based on simultaneous polysubstance use

BACKGROUND

Cannabis use patterns vary considerably, with many users reporting simultaneous and non-simultaneous use (co-use) of other substances. Despite this, little research has examined the extent to which subtypes of cannabis users may be identified based on their simultaneous and co-use behaviors.

METHODS

The sample consisted of adult Australian twins and siblings who reported lifetime cannabis use (n = 2590). A latent class analysis was conducted to determine subtypes of cannabis users based on five indicators of substance co-use and simultaneous use. Adolescent correlates (age of substance initiation and conduct disorder) and adult correlates (substance use/disorder and depression) of class membership were assessed. Twin similarity for class membership was also examined.

RESULTS

Four subtypes of users were identified: 1) alcohol co-users, 2) simultaneous alcohol users, 3) simultaneous tobacco users, and 4) simultaneous alcohol, tobacco, and drug users. Compared to co-users of alcohol, simultaneous alcohol users were at increased risk for alcohol problems. Patterns of use that involved simultaneous tobacco and cannabis use (i.e., simultaneous tobacco users and simultaneous alcohol, tobacco, and drug users) were associated with the most problematic outcomes, including substance use and disorder. There was evidence for genetic influences (12-58%) on cannabis use patterns, with higher concordance for latent class membership among monozygotic compared to dizygotic twins (χ2 (1) = 7.19, p = 0.007).

CONCLUSIONS

The current study identified four classes of cannabis users at varying degrees of risk. Results suggest that simultaneous tobacco and cannabis use may be especially associated with deleterious outcomes.

A longitudinal examination of daily patterns of cannabis and alcohol co-use among medicinal and recreational veteran cannabis users

BACKGROUND

Prompted by the ongoing debate regarding whether cannabis serves as a complement to or substitute for alcohol, this study uses prospective data to examine daily associations between medicinal versus recreational cannabis and alcohol use in veterans.

METHODS

Three semi-annual waves of Timeline Followback Interview data were collected from a sample of veterans who reported co-using alcohol and cannabis on at least one day (N = 115; 56% medicinal users; 93% male; 62,100 observations). Linear mixed effects models were used to examine the association between daily cannabis use and number of drinks consumed across time for both medicinal and recreational users and to examine the frequency medicinal cannabis used to substitute for alcohol.

RESULTS

Compared to medicinal users, recreational users were more likely to drink more on cannabis use days relative to non-use days. Among medicinal users, those endorsing more frequent use of cannabis as a substitute for alcohol reported fewer number of drinks consumed on days when cannabis was used relative to non-use days.

CONCLUSIONS

Among veterans, recreational users are at greater risk for increased drinking when co-using cannabis at the daily level, an association that is stable over time. Medicinal users may be at lower risk for increased drinking on days when cannabis is also used, especially those who endorse using cannabis to substitute for alcohol. Findings help clarify the debate on cannabis-alcohol substitution or complementary associations in a sample of veterans and suggests that alcohol interventions should address cannabis use as a risk factor, especially for recreational users.

Perceived Social Support from Significant Others among Binge Drinking and Polyconsuming Spanish University Students

Sense of acceptance is conceived as a central component of perceived social support and is thought to be a key resilience factor for adjustment during transition to university. The current study examines how a binge drinking pattern of alcohol consumption and the co-consumption of binge drinking and cannabis in first-year university students are related to perceived acceptance from family, mother, father, and friends. The study sample consisted of 268 women and 216 men, of average age 18.25 years (SE = 0.01), enrolled in the first year of different degree courses at the University of Santiago de Compostela. Participants were classified in three groups (control, binge drinking, polyconsuming) on the basis of the Timeline Followback for alcohol and cannabis. Perceived sense of acceptance was measured using the Perceived Acceptance Scale. Analysis of the data revealed that perceived acceptance was lower in polyconsuming students than in the binge drinking and control groups (p < 0.05; with η2 ranging between 0.009 and 0.020). A curvilinear relationship between binge drinking and perceived acceptance from friends was identified. Social support should be considered in future investigations and interventions as a vulnerability marker for detrimental consequences of substance use and risk of consumption disorders, as well as adolescent maladjustment.

Differential item functioning analysis of the CUDIT and relations with alcohol and tobacco use among men across five ethnic groups: The HELIUS study

Cannabis use has been rising despite recognition of the negative consequences associated with heavy use. The severity of these consequences has been shown to differ across racial/ethnic groups, even when controlling for consumption levels. The present study conducted an item response theory (IRT) analysis of the Cannabis Use Disorders Identification Test (CUDIT) to better understand the patterns of problematic cannabis use and their relation with other substance use across ethnic groups in the Healthy Life in an Urban Setting (HELIUS) study. CUDIT responses from 1,960 cannabis-using African Surinamese, South-Asian Surinamese, Dutch, Moroccan, and Turkish ethnic origin participants were used to test for differential item functioning (DIF) within an IRT framework. After restricting the sample to men because of low frequency of use among women, several instances of uniform DIF were identified. Multiple-group IRT analysis yielded a harmonized cannabis use phenotype that was used to estimate ethnic group differences in problematic cannabis use and its relation to alcohol and tobacco co-use. These analyses suggested that cannabis users from certain ethnic minority groups experienced higher rates of problematic use than the majority group despite lower rates of cannabis use. Further, cannabis and tobacco use were positively related across groups, whereas only ethnic minority groups showed a positive relation between cannabis and alcohol use. These results demonstrate the importance of accounting for DIF when examining group differences in problematic cannabis use, and support prior evidence suggesting that certain ethnic minority groups may be more likely to experience problematic cannabis use and alcohol co-use relative to the majority group. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Cannabinoids Exacerbate Alcohol Teratogenesis by a CB1-Hedgehog Interaction

We tested whether cannabinoids (CBs) potentiate alcohol-induced birth defects in mice and zebrafish, and explored the underlying pathogenic mechanisms on Sonic Hedgehog (Shh) signaling. The CBs, Δ⁹-THC, cannabidiol, HU-210, and CP 55,940 caused alcohol-like effects on craniofacial and brain development, phenocopying Shh mutations. Combined exposure to even low doses of alcohol with THC, HU-210, or CP 55,940 caused a greater incidence of birth defects, particularly of the eyes, than did either treatment alone. Consistent with the hypothesis that these defects are caused by deficient Shh, we found that CBs reduced Shh signaling by inhibiting Smoothened (Smo), while Shh mRNA or a CB1 receptor antagonist attenuated CB-induced birth defects. Proximity ligation experiments identified novel CB1-Smo heteromers, suggesting allosteric CB1-Smo interactions. In addition to raising concerns about the safety of cannabinoid and alcohol exposure during early embryonic development, this study establishes a novel link between two distinct signaling pathways and has widespread implications for development, as well as diseases such as addiction and cancer.

Marijuana and alcohol use among injured drivers evaluated at level I trauma centers in Arizona, 2008-2014

BACKGROUND

We examined marijuana and alcohol use trends among drivers aged ≥16 years evaluated at Level I trauma centers before and after Arizona legalized medical marijuana in April 2011.

METHODS

We conducted interrupted time series (ITS) analysis of urine drug screens for marijuana metabolites and blood alcohol concentration (BAC) data from the 2008-2014 Arizona State Trauma Registry.

RESULTS

Among 30,083 injured drivers, 14,710 had marijuana test results, and 2590 were positive for marijuana; of these, 1087 (42%) also tested positive for alcohol. Among 23,186 drivers with BAC results, 5266 exceeded the legal limit for their age. Compared with prelaw trends (models if law had not been enacted), postlaw models showed small but significant annual increases in the proportions of drivers testing positive for either substance. By the end of 2014, the proportion of drivers testing positive for marijuana was 9.6% versus a projected 5.6% if the law had not been enacted, and the proportion of drivers with illegal BACs was 15.7% versus a projected 8.2%. When ITS was restricted to only substance-tested drivers, no significant differences were detected.

CONCLUSIONS

Despite the small annual postlaw increases in the proportion of marijuana-positive drivers compared with the prelaw trend, alcohol-impaired driving remains a more prevalent threat to road safety in Arizona.

Behavioral economic demand for alcohol among young adults who engage in simultaneous alcohol and marijuana use

Background: Young adults (YAs) who engage in simultaneous alcohol and marijuana use (SAM) may combine substances due to enhanced subjective effects, and as a result, may place greater value (e.g., spend more resources) on alcohol relative to YAs who consume alcohol but do not engage in SAM. The aim of the current study was to evaluate behavioral economic demand for alcohol among YAs who reported SAM (n = 101) relative to alcohol use only (n = 316), and concurrent alcohol and marijuana use (CAM; n = 63). Methods: YAs (18-25 years old) recruited from the community completed an online assessment that included the Alcohol Purchase Task as well as past month alcohol, marijuana, and SAM use. Results: Analyses of covariance demonstrated that YAs who reported SAM had significantly higher O_max values (maximum overall expenditures on alcohol) than those who reported CAM, and both YAs who reported SAM and alcohol-only had significantly higher P_max values (maximum inelastic price per drink) than YAs who reported CAM. Conclusions: YAs that engage in SAM show an increased willingness to spend resources on alcohol. Elevated demand is not associated with concurrent use of multiple substances, but rather the combined (i.e., overlapping) use of substances.

Adolescent Brain Surface Area Pre- and Post-Cannabis and Alcohol Initiation

OBJECTIVE

Changes in gray matter volume and thickness are associated with adolescent alcohol and cannabis use, but the impact of these substances on surface area remains unclear. The present study expands on previous findings to examine the impact of alcohol and cannabis on surface area before and after use initiation.

METHOD

Scans for 69 demographically similar youth were obtained at baseline (ages 12-14 years; before substance use) and at 6-year follow-up (ages 17-21 years). Participants were classified into three groups based on substance use: alcohol use initiators (ALC, n = 23), alcohol and cannabis use initiators (ALC+CU, n = 23), and individuals with minimal substance use (<3 lifetime alcohol and 0 marijuana use episodes; CON, n = 23). For each hemisphere, group differences in surface area across time (pre- and post-substance use initiation) and significant group-by-time interactions were examined individually for 34 cortical regions using repeated measures analysis of covariance. A vertex-wise analysis assessed group differences in surface area percent change.

RESULTS

A significant group-by-time interaction was found in three regions, bilateral medial orbitofrontal cortices and right insula. Although all regions showed decreases in surface area over time (ps < .05), a more substantial decrease was identified in the ALC group. Of note, the right medial orbitofrontal cortex survived the conservative vertex-wise analyses (p < .001), as a more substantial decrease was found in the ALC compared to the ALC+CU group in this region.

CONCLUSIONS

Surface area in the medial orbitofrontal cortex may be a useful intermediate phenotype for exploring the mechanisms underlying the effects of substance use on brain development.

Consequences of Perinatal Cannabis Exposure

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

Polysubstance Use by Stimulant Users: Health Outcomes Over Three Years

OBJECTIVE

Studies show that stimulant users have varied substance use patterns and that polysubstance use is associated with poorer past or concurrent medical, mental health, and substance use outcomes. This study examined outcomes of substance use patterns prospectively.

METHOD

A latent class analysis was conducted to examine substance use patterns among adults using stimulants (n = 710; 38.6% women) at baseline, and the health and treatment utilization outcomes of different use patterns over the subsequent 3 years. To examine associations between latent class membership and outcomes, generalized estimating equation modeling was conducted.

RESULTS

Four classes of substance use patterns at baseline were identified, involving high use of (a) methamphetamine and marijuana (23%); (b) crack cocaine and alcohol (25%); (c) powder cocaine, alcohol, and marijuana (23%); and (d) nonprescribed opioids, alcohol, marijuana, crack cocaine, and powder cocaine (i.e., polysubstance [29%]). Polysubstance class members had poorer physical health and mental health status, and more severe substance use, over the subsequent 3-year period, than other class members. Regarding treatment utilization, polysubstance class members had more medical care utilization than crack cocaine class members, and more substance use treatment utilization than powder cocaine class members. The methamphetamine, crack cocaine, and powder cocaine classes did not differ from each other on any health or treatment utilization outcome.

CONCLUSIONS

People using stimulants commonly use other substances, and those whose polysubstance use includes nonprescribed opioids have especially poor health outcomes.

Binge Drinking Among Older Adults in the United States, 2015 to 2017

OBJECTIVES

Binge drinking is a risk factor for a range of harms. This study estimates the national prevalence of binge drinking and adds to our understanding of correlates of binge drinking among older adults in the United States.

DESIGN

Cross-sectional analysis.

SETTING/PARTICIPANTS

A total of 10 927 adults, aged 65 years or older, from the 2015 to 2017 administrations of the US National Survey on Drug Use and Health.

MEASUREMENTS

We estimated the prevalence of past-month binge alcohol use (five or more drinks on the same occasion for men and four or more drinks on the same occasion for women). Characteristics of past-month binge drinkers, including demographics, substance use, serious mental illness, mental health treatment utilization, chronic disease, and emergency department (ED) use, were compared to participants who reported past-month alcohol use without binge drinking. Comparisons were made using χ2 tests. We then used multivariable generalized linear models using Poisson and log link to examine the association between covariates and binge drinking among all past-month alcohol users aged 65 years or older.

RESULTS

Of 10 927 respondents, 10.6% (95% CI = 9.9%-11.2%) were estimated to be current binge drinkers. Binge drinkers were more likely to be male, have a higher prevalence of current tobacco and/or cannabis use, and have a lower prevalence of two or more chronic diseases compared to nonbinge drinkers. In multivariable analysis, among past-month alcohol users, the prevalence of binge drinking was higher among non-Hispanic African Americans than whites (adjusted prevalence ratio [aPR] = 1.44; 95% CI = 1.16-1.80), tobacco users (aPR = 1.52; 95% CI = 1.33-1.74), cannabis users (aPR = 1.41; 95% CI = 1.11-1.80), and those who visited the ED in the past year (aPR = 1.16; 95% CI = 1.00-1.33).

CONCLUSION

Over a tenth of older adults in the United States are estimated to be current binge drinkers. Results confirm the importance of screening for binge drinking behaviors among older adults to minimize harms. J Am Geriatr Soc 67:2139-2144, 2019.

Joint and separate exposure to alcohol and ∆9-tetrahydrocannabinol produced distinct effects on glucose and insulin homeostasis in male rats

Cannabis and alcohol co-use is common, and the trend may increase further given the current popularity of cannabis legalization. However, the metabolic consequences of such co-use are unclear. Here, we investigated how co-administration of alcohol and ∆9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, affects body weight and visceral adiposity, and glucose and insulin homeostasis in rats. For 16 consecutive days during adolescence, male rats drank saccharin or alcohol after receiving subcutaneous oil or THC injections in Experiment 1 and voluntarily consumed alcohol, THC edible, or both drugs in Experiment 2. Experiment 1 showed that following abstinence, drug co-exposure reduced visceral fat and the amount of insulin required to clear glucose during an oral glucose tolerance test (OGTT). In Experiment 2, rats received a high-fat diet (HFD) after 3-week abstinence. Although adolescent drug use did not interact with the HFD to worsen hyperglycemia and hyperinsulinemia during an OGTT, HFD-fed rats that co-used alcohol and THC had the lowest insulin levels 75 min after an insulin injection, suggesting an altered rate of insulin secretion and degradation. These results suggest that THC and alcohol co-exposure can distinctly alter the physiology of glucose and insulin homeostasis in a rodent model.

Subgroup trends in alcohol and cannabis co-use and related harms during the rollout of recreational cannabis legalization in Washington state

BACKGROUND

The US state of Washington legalized recreational cannabis in 2012; how this impacted the co-use of cannabis and alcohol in the population overall and among key subgroups has not been examined. The aim of this study is to investigate changes in patterns of alcohol- and cannabis use and alcohol-related harms during the rollout of retail recreational cannabis stores.

METHODS

Data come from six cross-sectional samples recruited between January 2014-October 2016 via Random Digit Dial procedures (N = 5492). Survey-weighted multivariable regression adjusting for gender, age, race/ethnicity, education, employment, marital status, cannabis use, and survey year were used for statistical analyses.

RESULTS

In the sample overall, no significant changes were observed in any alcohol use measures between 2014-2016, while the prevalence of cannabis use significantly (P < 0.05) increased from 25.0% to 31.7%, the prevalence of alcohol-related harms at home significantly decreased from 2.1% to 1.0%, and the prevalence of alcohol-related financial harms decreased from 1.5% to 0.8%. Both women and men significantly increased any cannabis use, while women also experienced significantly fewer alcohol-related harms at home and financial harms over time, and increases in the prevalence of cannabis users/non-drinkers. Those 18-29 years old significantly reduced the number of drinking days and overall volume in the past 30 days, and those 30-49 years old significantly decreased alcohol-related harms at home and financial harms. Those 50+ years old significantly increased any cannabis use and simultaneous use of cannabis and alcohol. Non-cannabis users slightly decreased average number of drinks/day, and cannabis users significantly decreased alcohol-related financial harms.

CONCLUSIONS

Between 2014-2016, the years during and immediately following the introduction of legal recreational cannabis stores in Washington state, there were no significant changes in cannabis and alcohol co-use or overall alcohol consumption. The only significant changes in the sample overall were an increase in any cannabis use and decreases in alcohol-related harms at home and alcohol-related financial harms.

Simultaneous Use of Alcohol and Marijuana: Patterns and Individual Differences

Background: Simultaneous alcohol and marijuana (SAM) use, or using alcohol and marijuana in such a way that their effects overlap, is associated with negative health and behavioral outcomes. Objectives: Our study sought to fill gaps in our knowledge on this emerging public health concern by comparing SAM users and alcohol-only users on individual-level factors and substance use outcomes as well as examining associations of SAM use frequency, within users. Methods: Participants were recruited through online postings. Our analytic sample consisted of 1017 young adults (18-25 years) who reported past-month alcohol use. Most were male (67.8%), Caucasian (71.5%), and had attended at least some college (74.8%). Results: Past-year SAM users reported higher levels of sensation seeking and greater perceptions of their close friends' drinking behavior in comparison to alcohol-only users. SAM users reported heavier and more frequent alcohol use than alcohol-only users. Within past-year SAM users, 70% reported SAM use at least weekly. More frequent SAM use was associated with all alcohol use outcomes (e.g., weekly quantity, frequency, alcohol-related problems) and marijuana use outcomes (e.g., quantity, frequency, peak use) and higher drinking norms. Conclusions/Importance: It is clear that SAM users are a vulnerable sub-population of young adult drinkers. SAM users are differentiated from alcohol-only users in terms of their personality characteristics and perceptions of peer groups' drinking. SAM users and more frequent users are also at heightened risk for substance use outcomes. Prevention and intervention efforts targeting high-risk drinking may benefit from also assessing whether they simultaneously use alcohol and marijuana.

Simultaneous Alcohol and Marijuana Use Among College Students: Patterns, Correlates, Norms, and Consequences

BACKGROUND

Alcohol and marijuana users often engage in simultaneous alcohol and marijuana (SAM) use (i.e., using the 2 substances together so that their effects overlap), which can result in more negative consequences than using either substance alone. Nevertheless, little is known about SAM use among contemporary college students to aid in the development of preventive interventions. This study examined SAM use patterns, demographic correlates of SAM use, and normative influences on SAM use and related negative consequences among college students.

METHODS

Students who had used alcohol and marijuana in the past year were recruited from 3 state universities in states with different laws regarding recreational marijuana use (N = 1,389). They completed an online survey, which assessed their own alcohol, marijuana, and SAM use and related consequences, their perceptions of the proportion of same-gender peers and close friends who engaged in SAM use, marijuana access, and demographic characteristics.

RESULTS

About three-fourths of participants reported at least 1 occasion of SAM use in the past year with an average frequency of twice per month among SAM users. There were significant differences in SAM use prevalence and frequency by sociodemographic characteristics controlling for past-year alcohol and marijuana frequency. Students in a state with decriminalized recreational marijuana use reported higher frequency of past-year SAM use than students in states with legalized or criminalized use. There were significant demographic differences in perceived norms regarding SAM use among close friends and same-gender peers. SAM users endorsed significantly higher perceived peer and friend norms than nonusers. Also, higher perceived norms predicted more frequent SAM use and more negative consequences of use.

CONCLUSIONS

Results indicate a need for prevention programs on college campuses that address SAM use. Interventions that use personalized normative feedback may be effective.

Are Co-users of Alcohol and Marijuana More Willing to Experience Consequences From Drinking? A Longitudinal Examination Among First-Year College Students

BACKGROUND

Alcohol and marijuana co-users are at heightened vulnerability for experiencing a variety of negative alcohol use outcomes including heavier alcohol use and driving under the influence. The current study explored willingness to experience negative consequences as a potential factor underlying the association between co-user status and negative consequences in an effort to guide future intervention work. From a longitudinal study of first-year college students, we examined willingness to experience consequences at Time 2 as a mediator of co-user status at Time 1 and experience of negative consequences at Time 3.

METHODS

First-year college student drinkers (n = 1,914) at a large university completed surveys in the fall and spring of their freshman year and the fall of their sophomore year.

RESULTS

Alcohol and marijuana co-users reported higher willingness to experience consequences than alcohol-only users. Willingness to experience consequences partially explained the association between alcohol and marijuana couse and consequences.

CONCLUSIONS

The current study was the first to compare co-users of alcohol and marijuana to alcohol-only users on willingness to experience consequences, and examine the role of willingness as a mediator between co-user status and consequences experienced. Co-users were more willing to experience adverse effects from drinking, in turn predicting more consequences. Intervention work targeting consequences may be less effective for co-users; thus, additional work is needed to identify other potential mechanisms for change for this at-risk group.

Daily Motives for Alcohol and Marijuana Use as Predictors of Simultaneous Use Among Young Adults

OBJECTIVE

Research on substance use motives typically examines each substance separately. However, simultaneous alcohol and marijuana (SAM) use-that is, using alcohol and marijuana at the same time so that their effects overlap-is common among young adults. This study examines day-to-day fluctuations in motives for using alcohol and/ or marijuana among young adult substance users as predictors of alcohol, marijuana, and SAM use across days.

METHOD

Data were from a community sample of young adults who reported SAM use in the past month (analytic sample: N = 399, mean [SD] age = 21.63 [2.17]; 50.9% women). Participants reported alcohol, marijuana, and SAM use, and also motives "for alcohol and/or marijuana use" for 14 consecutive days.

RESULTS

Multilevel models showed that elevated enhancement motives were associated with heavy episodic drinking, drinking more, and more hours high from marijuana. Elevated social motives were associated with heavy episodic drinking and drinking more, and also with fewer hours high. Elevated conformity motives were associated with drinking more. SAM use was more likely: on alcohol days and on marijuana days with elevated enhancement and conformity motives, on alcohol days with elevated coping motives, and on marijuana days with elevated social motives.

CONCLUSIONS

SAM use on a given day was primarily associated with enhancement and conformity motives. Social motives were more strongly linked to alcohol use, and to some extent coping motives were linked to marijuana use in this young adult sample. Further examination of situation-specific motives and contexts of use is needed to inform development of real-time interventions for SAM use and consequences.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Concurrent use of addictive substances among alcohol drinkers: Prevalence and problems in a Swedish general population sample

Aims:

To examine concurrent use of addictive substances among alcohol drinkers in the Swedish general population and to assess to what extent this increases the risk of alcohol problems.

Methods:

Data were retrieved from a nationally representative survey from 2013 on use of and problems related to alcohol, tobacco, illicit drugs and non-prescribed use of analgesics and sedatives with 15,576 respondents. Alcohol users were divided into different groups on the basis of frequency of drinking overall and binge drinking. Tobacco use was measured in terms of daily use and use of illicit drugs and non-prescribed use of analgesics and sedatives were measured in terms of last 12 months prevalence. A dichotomous indicator of a DSM-IV dependence or abuse diagnosis was used. Logistic regression models were estimated to examine the relationship between various patterns of drinking in combination with other substance use and risk of alcohol abuse and/or dependence.

Results:

People who drink alcohol in Sweden were more likely to use other addictive substances than non-drinkers and such concurrent use becomes more common the more alcohol is consumed. Alcohol drinkers using other substances have a higher prevalence of alcohol abuse and dependence at all frequencies of drinking. Multivariate models controlling for sex, age and drinking frequency found that an elevated risk of harm remained for drinkers using addictive substances other than snuff.

Conclusion:

A large group of drinkers in the Swedish general population have an accumulation of risks as a result of using both alcohol and other addictive substances. Concurrent use of cigarettes, illicit drugs and non-prescribed use of analgesics and sedatives adds an independent risk of alcohol abuse/dependence in this group in addition to their drinking. The findings point at the importance of taking multiple substance-use patterns into account when combating drinking problems. Screening for concurrent use of other addictive substances could help healthcare providers to identify patients in need of treatment for alcohol problems.

Trends and correlates of driving under the influence of alcohol among different types of adult substance users in the United States: a national survey study

Background

Despite a decrease in driving under the influence of alcohol (DUIA) prevalence over the past decades, DUIA prevalence still remains high in the United States. To date, there is limited research examining whether different types of substance users have different trends in DUIA. This study sought to assess trends and variables associated with DUIA by substance use type.

Methods

National Survey on Drug Use and Health (NSDUH) is a cross-sectional, nationally representative population-based survey. By using the NSDUH 2008–2014, we performed the Joinpoint analysis to identify time trends of DUIA in each group of substance users (aged ≥18 years). Logistic regression analysis was used to explore association between substance use type and DUIA and to identify variables associated with DUIA.

Results

Adults who reported alcohol or drug use in the past year were classified into different groups based on past-year substance use status: alcohol use only (n = 141,521) and drug use regardless alcohol use. Drug users included prescription opioids only (n = 5337), marijuana only (n = 32,206), other single drug (n = 3789), prescription opioids-marijuana (n = 3921), multiple prescription drugs (n = 1267), and other multiple drugs (n = 18,432). The Joinpoint analysis showed that DUIA prevalence decreased significantly from 2008 to 2014 among alcohol only users (Average Annual Percent Change [AAPC] = − 2.8), prescription opioids only users (AAPC = -5.4), marijuana only users (AAPC = -5.0), prescription opioids-marijuana users (AAPC = -6.5), multiple prescription drug users (AAPC = -7.4), and other multiple drug users (AAPC = -3.2). Although the estimate was not statistically significant, other single drug users showed a decreasing trend (AAPC = -0.9). Substance use type was significantly associated with DUIA in the adjusted logistic regression. All drug use groups, relative to the alcohol only group, had elevated odds of DUIA, and the odds were especially elevated for the multiple drug use groups (prescription opioids-marijuana, adjusted odds ratio [AOR] = 2.71; multiple prescription drugs, AOR = 2.83; and other multiple drugs, AOR = 3.68). Additionally, younger age, male sex, being white, higher income, and alcohol abuse/dependence were positively associated with DUIA.

Conclusions

DUIA prevalence decreased over time and the magnitude of this reduction differed by substance use type. DUIA interventions need to be tailored to substance use type and individual characteristics.

Spirits purchasing and marijuana use behaviors of risky drinkers in the state of Washington from 2014 to 2016

BACKGROUND

Few studies have evaluated alcoholic beverage purchasing behaviors, which are relevant to the design and effectiveness of alcoholic beverage control policies. Focusing on spirits purchasing among spirits drinkers, this study compares purchasing behaviors between risky and non-risky drinkers and across drinking patterns among those observed drinking at both levels.

METHODS

A rolling panel of 794 spirits drinkers in the state of Washington were surveyed between two and five times at 6-month intervals during 2014, 2015 and 2016 regarding their alcohol use, spirits purchasing and marijuana use frequency. Purchasing behaviors assessed for spirits were the frequency of purchasing and the travel time, unit cost, bottle size and store type from the respondents most recent purchase. Alcohol use was categorized at each measurement as risky or not using US NIAAA guidelines.

RESULTS

Risky drinkers were more likely to purchase spirits, purchase spirits more frequently, purchase larger spirits containers and use marijuana occasionally, but not frequently. Among drinkers who were risky only in some survey waves, during risky waves they were more likely to purchase more frequently, pay less per liter for spirits purchased, buy larger sized containers of spirits and use marijuana occasionally.

CONCLUSIONS

Drinkers chose to purchase lower cost spirits in larger containers when they were drinking more heavily compared to times when they were drinking within US low-risk guidelines. Findings also support complementarity between heavier drinking and marijuana use among spirits drinkers in a state with legal recreational marijuana sales.

An examination of consequences among college student drinkers on occasions involving alcohol-only, marijuana-only, or combined alcohol and marijuana use

This event-level study examined within-person differences in consequences for college students who engaged in alcohol-only, marijuana-only, or simultaneous alcohol and marijuana (SAM) use across 18 weekend days. Participants (n = 451) were asked to report consequences they experienced on each occasion across five different types of events: (a) heavier alcohol combined with marijuana; (b) lighter alcohol combined with marijuana; (c) heavier alcohol only; (d) lighter alcohol only; and (e) marijuana only. Occasions involving heavy drinking, alone and in combination with marijuana, were associated with higher rates of consequences relative to lighter alcohol-only occasions, lighter alcohol combined with marijuana occasions, and marijuana-only occasions. Light alcohol-only occasions did not significantly differ on consequences from lighter alcohol combined with marijuana occasions or marijuana-only occasions. Past research has shown SAM use is associated with more consequences compared with alcohol-only use. The current findings suggest that SAM use is not necessarily riskier than drinking or using marijuana alone. Results suggested that on heavy drinking occasions, the number of consequences did not significantly change by also using marijuana. Findings suggest the benefit of targeted intervention strategies to reduce harms associated with heavy drinking occasions with and without SAM use. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Patterns of alcohol use and marijuana use among students at 2- and 4-year institutions

Objective: The objective of this study was to understand substance use patterns of alcohol, marijuana, and simultaneous alcohol and marijuana (SAM) use among 2- and 4-year college students. Participants: Participants were 526 young adults aged 18-23 (n = 355 4-year students; n = 171 2-year students) recruited from February 2015 to January 2016 who were participating in a larger longitudinal study. Methods: Latent class analysis (LCA) was used to identify past-month classes of alcohol, marijuana, and SAM use. Results: Among both 2- and 4-year students, a four-class solution yielded the best-fitting model, with 2-year classes tending to include greater marijuana use and less alcohol use and 4-year classes tending to include heavy alcohol use. Demographic characteristics were largely similar across classes. Conclusions: Classes of alcohol, marijuana, and SAM use differed by education status. Screening and prevention efforts for 4-year students may need to be tailored for the needs of 2-year students.