Trends in cannabis and tobacco co-use in the United States, 2002-2021.

BACKGROUND: Co-use of cannabis and tobacco poses greater risks than use of either substance individually and may be becoming more prevalent with increasing cannabis medicalization and legalization. We aimed to assess trends in the prevalence of cannabis and tobacco co-use between 2002-2019 and identify the updated prevalence and correlates of co-use in 2021 among US adults. METHODS: This study used data from the 2002-2021 National Survey on Drug Use and Health, a nationally-representative, cross-sectional survey in the US. We assessed prevalence trends in past 30-day cannabis and tobacco co-use, exclusive cannabis use, and exclusive tobacco use overall and by sociodemographic group using joinpoint regression. Additionally, multinomial models identified correlates of co-use in 2021. RESULTS: In 2021, the weighted prevalence of cannabis and tobacco co-use was 6.38 %, the weighted prevalence of exclusive cannabis use was 7.28 %, and the weighted prevalence of exclusive tobacco use was 15.01 %. From 2002 to 2019, the prevalence of past 30-day co-use of cannabis and tobacco increased significantly (annual percentage change [APC]: 1.9 [1.4-2.4], P<0.05) among the overall US population. All subgroups of sex, race/ethnicity, and age also saw significant increases in co-use, other than young adults ages 18-25, for whom co-use was stagnant between 2002-2014 and then decreased significantly between 2014-2019. CONCLUSION: This study identified increasing cannabis and tobacco co-use overall and among most sociodemographic strata in the US. As cannabis policy changes rapidly, co-use requires closer surveillance, clinical screening, and dedicated research.

Examining the influence of cigar and cannabis co-marketing on packaging perceptions: An experiment with a sample of US youth.

SIGNIFICANCE: Cigars are sometimes marketed with cannabis references because they are often used for smoking blunts (i.e., cannabis rolled in cigar paper with or without tobacco). However, little research exists on the impact of cannabis co-marketing on cigar perceptions. METHODS: Participants included 506 US youth (ages 15-20) recruited April-June 2023 through Qualtrics who reported ever using little cigars or cigarillos (LCCs), past 30-day use of LCCs, or susceptibility to using LCCs. We then conducted a between-subjects experiment, randomizing youth to view one of two cigarillo packages: 1) a package with cannabis co-marketing (i.e., the package included a cannabis-related flavor descriptor and the word "blunt" appeared in the brand name and product label) or 2) a package with no cannabis co-marketing. We assessed the effects of the packaging on perceptions of product ingredients, addictiveness and harm perceptions, product appeal, susceptibility to using the product shown, and purchase intentions. RESULTS: Packages with cannabis co-marketing were perceived as more likely to contain cannabis (OR: 5.56, 95 % CI: 3.73, 8.27) and less likely to contain tobacco (OR: 0.42, 95 % CI: 0.25, 0.70) or nicotine (OR: 0.57, 95 % CI: 0.40, 0.82). Cannabis co-marketing also led to higher susceptibility to using the product shown (B: 0.21, p = 0.02). We did not find evidence that cannabis co-marketing changed harm perceptions or purchase intentions. CONCLUSIONS: Among a sample of US youth, cannabis co-marketing on cigar packages may change perceptions of product ingredients and increase susceptibility to using such products, which could lead to the initiation of cigars and cannabis.

Alcohol and cannabis use in daily lives of college-attending young adults: Does co-use correspond to greater reported pleasure?

Co-use of alcohol and cannabis is prevalent and linked with heightened risk for substance-related harms. The current study investigated the role of substance-related pleasure as a reinforcing factor for co-use relative to alcohol or cannabis use. Specifically, we used data from a 21-day diary study of college students to examine day-level associations between co-use and self-reported substance-related pleasure (any, level of pleasure). Participants were 237 college students (65 % female sex at birth, ages 18-24) who reported 1+ alcohol and cannabis co-use occasion. Participants completed daily surveys across 21 consecutive days about yesterday's substance use and experiences of pleasure, yielding 2,086 daily surveys involving alcohol and/or cannabis use. Multilevel models indicated that odds of substance-related pleasure were higher on days with co-use relative to days with single-substance use, and level of pleasure was higher on co-use days relative to cannabis but not alcohol use days. Pleasure may serve as a reinforcing property of co-use that may be related to continued use despite experience of negative consequences. Intensity of pleasure related to co-use appears to be largely driven by use of alcohol. However, given mixed findings concerning level of pleasure, individuals may report co-use increases feelings of pleasure but do not actually experience more pleasure. Pleasure may serve as a viable target in future prevention and intervention programming targeting co-use.

Longitudinal patterns of alcohol and cannabis use among US young adults: Correlates and implications for problematic health outcomes.

INTRODUCTION: Alcohol and cannabis use are common during young adulthood. Less is known regarding correlates of alcohol-cannabis use patterns and related problematic health outcomes. METHODS: Using longitudinal survey data (Fall 2018, 2019, 2020) from 2,194 young adults (YAs; ages 18-34), bivariate analyses and multivariable logistic regressions examined: (1) Wave 1 (W1) sociodemographics and psychosocial factors (i.e., adverse childhood experiences [ACEs], depressive symptoms, personality traits, parent and peer alcohol and cannabis use) in relation to W3 past-month use group (i.e., use of neither, alcohol only, cannabis only, both/co-use); and (2) W3 use group in relation to W5 problematic alcohol use (Alcohol Use Disorder Identification Test), problematic cannabis use (Cannabis Use Disorder Identification Test), and depressive/anxiety symptoms (Patient Health Questionnaire - 4 item). RESULTS: Overall, 42.3% reported W3 alcohol-only use, 34.9% co-use, 17.8% no use, and 5.0% cannabis-only use. Those reporting W3 co-use reported greater W1 extraversion, openness, friend alcohol/cannabis use, and were more likely to report parent cannabis use (vs. no use); reported less conscientiousness, greater friend cannabis use, and were more likely to report depressive symptoms and parent cannabis use (vs. alcohol-only use); and reported greater friend alcohol use, and were more likely to report parent alcohol use (vs. cannabis-only use). W3 co-use was associated with higher odds of W5 problematic alcohol use (vs. alcohol-only use) and problematic cannabis use (vs. cannabis-only use). CONCLUSIONS: Substance use messaging and interventions should consider YAs' alcohol-cannabis co-use and the unique correlates of such use.

Examining the moderating role of cannabis use on the relationship between alcohol consumption and inflammation in individuals with alcohol use disorder.

Inflammation appears to be a critical mechanism in the development of alcohol use disorder (AUD) and a consequence of chronic alcohol use. The potential anti-inflammatory properties of cannabis may modulate the proinflammatory effects of alcohol. This study sought to extend previous work investigating the relationship between alcohol consumption, cannabis use and circulating interleukin (IL)-6 levels in a sample with AUD. One hundred and thirty-three individuals with an AUD provided blood samples to assess IL-6 and answered questions regarding alcohol and cannabis use. An ordinary least squares multiple regression analysis was conducted to assess the effect of alcohol and cannabis use on IL-6. A moderation analysis examined cannabis use as a potential moderator of the relationship between alcohol use and circulating IL-6 levels. Alcohol use was predictive of higher log IL-6 levels (standardized ß = 0.16, p = 0.03), while cannabis use was not predictive of log IL-6 levels (p = 0.36). Days of cannabis use moderated the relationship between alcohol use and IL-6 levels, such that the relationship between alcohol use and IL-6 levels was only significant in individuals with AUD without recent cannabis use. This study extends previous work to a clinical sample with an AUD and underscores the importance of considering cannabis use in studies on alcohol use and inflammation. This study also indicates the need for in-depth analyses on cannabinoids and inflammation and the interaction between cannabinoids and alcohol use on inflammation.

Products and patterns through which adolescents, young adults, and adults initiate co-use of tobacco and cannabis.

BACKGROUND: Co-use of tobacco and cannabis is common. However, few studies have examined the temporal sequencing through which individuals initiate co-use, and how these patterns vary across age. This study addresses this gap by examining the specific products and temporal sequencing through which adolescents, young adults, and adults initiate co-use of tobacco and cannabis. Among adolescents, young adults, and adults who co-used tobacco and cannabis in the past 30 days, we examined (a) whether tobacco or cannabis was used first in their lifetime and (b) which specific tobacco or cannabis product (e.g., nicotine e-cigarettes, cannabis edibles) was the first used. METHODS: Data were from a cross-sectional national survey (N = 6,131, 13-40 years old) in which participants reported ever use, past-30-day-use, and order of use for 17 different tobacco and cannabis products. Results were analyzed overall and by age group (13-20; 21-24; 25-40). RESULTS: 38.4% of participants reported use of both tobacco and cannabis in the past 30 days. Among these participants, 70.9% used tobacco first in their lifetime (66.6% < 21; 71.7% 21-24; 76.6% > 24). Approximately 60% of participants who initiated co-use with tobacco reported nicotine e-cigarettes as their first tobacco product (63.3% < 21; 66.7% 21-24; 49.6% > 24). CONCLUSIONS: The majority of participants who used both tobacco and cannabis used tobacco first in their lifetime, and nicotine e-cigarettes were the most common form of tobacco initiation, particularly among adolescents and young adults. Findings emphasize the need for co-use prevention programs to target common products of initiation.

The underrepresentation of racial/ethnic minorities in research on co-use of nicotine, alcohol, and/or cannabis via ecological momentary assessment methods: A narrative review.

BACKGROUND: Co-use of nicotine, alcohol and/or cannabis is common among adults in the United States. Co-use may represent greater addiction severity than single substance use. Recent studies have examined the extent to which the frequency, order, simultaneity, motivations, and contextual factors associated with co-use differ from that of single use. Co-use has become prevalent among racial/ethnic minority individuals who exhibit distinct co-use patterns and related outcomes; however, most of these studies rely on cross-sectional or sparse longitudinal observations. Ecological momentary assessment (EMA) can illuminate such patterns and associations with time-varying contexts. This review summarizes EMA studies on co-use published from 2008 to 2023 involving racial/ethnic minority individuals and point to gaps. Our review addresses: 1) whether use of one substance leads to substitution or complementary use of another, 2) whether antecedents/contexts differ by co-use patterns and minority status, and 3) what consequences of co-use have been documented across co-use patterns or minority status. METHODS: Search results yielded 465 articles, with 33 meeting inclusion criteria. We extracted study-level characteristics and synthesized the findings. RESULTS: The findings largely focused on co-use patterns, categories of co-use, proximal antecedents and contexts, and consequences. Variations by minority status were rarely examined; few examined acute effects of unique experiences that may contribute to co-use among racial/ethnic minority adults. CONCLUSIONS: The EMA literature on co-use is burgeoning in recent years and supports complementary hypothesis. More research to capture time-intensive data on experiences to contextualize the co-use among racial/ethnic minority groups with greater diversity in race/ethnicity is warranted.

"It frees your body from that pain thought": A mixed-methods exploration of patterns, contexts, and experiences of cannabis use for pain in rural communities.

U.S. adults increasingly report using cannabis to manage chronic pain and rural areas have inadequate comprehensive pain management. Using mixed methods, we aimed to understand how and why some rural adults use cannabis for pain, including within the context of co-use with opioids. Participants (N = 14, Oklahoma) were rural-dwelling adults who used tobacco and ≥1 other substance, including cannabis and opioids, ≥3 days per week. Participants completed 14 days of ecological momentary assessment (EMA) regarding substance use and subsequent in-depth interviews discussing maps of their substance use reports. Half (7/14) described cannabis use for chronic pain, and most of these (85%) reported use on ≥75% of EMA days. The most frequently reported cannabis use motive was therapeutic/medicinal (90% of use reports). Most reports were of combusted cannabis (88% of use reports) at home (99% of use reports). Same-day use of cannabis and opioids was relatively common (45% of daily surveys), but seemingly not within close temporal proximity. Interview narratives characterized cannabis as modifying pain-adjacent factors (eg, thoughts), not eliminating pain itself. They recounted using a repertoire of substances to manage different pain dimensions (eg, intensity, quality) and balance perceived trade-offs of different substances. Participants described high medical cannabis access, low pain specialist access, and most physicians as unwilling to discuss cannabis for pain. The findings suggest that rural-dwelling patients could benefit from increased access to comprehensive pain management, having cannabis addressed within pain management provider discussions, and that risks and benefits of cannabis use for pain must be better established. PERSPECTIVE: This study used a geographically explicit EMA mixed method to gather rich, intensive pilot data on cannabis use and co-use for chronic pain in rural Oklahoma. It provides unique insights to inform future research on cannabis use among a vulnerable and understudied subgroup of adults with pain-rural residents.

Intention to quit or reduce e-cigarettes, cannabis, and their co-use among a school-based sample of adolescents.

INTRODUCTION: Little is known about the prevalence and predictors of adolescents' intention to quit or reduce use of e-cigarettes and/or cannabis. METHODS: Frequencies of intention to change (quit, reduce) e-cigarettes and/or cannabis use were examined among 23,915 surveyed middle and high school students with sole and co-use. Predictors of intention to change were identified via LASSO/multilevel logistic regression. RESULTS: Among those with sole e-cigarette use (n = 543), 40.9 % intended to quit and 24.1 % intended to reduce; non-daily e-cigarette use predicted intention to quit and reduce e-cigarettes (p's < 0.03). Among those with sole cannabis use (n = 546), 10.6 % intended to quit and 25.1 % intended to reduce; absence of cannabis cravings predicted intention to reduce cannabis use (p < 0.01). Among those with co-use (n = 816), 26.2 % intended to either quit or reduce (quit/reduce) both substances, 27.5 % intended to quit/reduce e-cigarettes only, and 6.9 % intended to quit/reduce cannabis only. No predictors emerged for intention to change e-cigarette use among those with co-use (p's > 0.09), but younger age, lack of poly-tobacco use, and lack of cannabis craving predicted intention to quit/reduce cannabis use (p's < 0.04). CONCLUSIONS: More than half of adolescents with past-month e-cigarette use, regardless of concurrent cannabis use, expressed interest in changing their use. However, only heaviness of e-cigarette use emerged as a predictor of intention to change suggesting. While fewer students expressed interest in changing their cannabis use, cannabis cravings and poly-tobacco use predicted intent to change. Overall, findings emphasize the need to tailor interventions towards adolescents engaging in more problematic substance use patterns.

E-cigarettes in college: Associations between mental health and e-cigarette use with other substances.

INTRODUCTION: College students are a priority population for substance use prevention, and other studies have reported associations between mental health and e-cigarette use. This study described the association of mental health to e-cigarette and other substance use (ECIG+ use) among US college students. METHODS: We used Fall 2018 and Spring 2019 National College Health Assessment data among undergraduate students aged 18-24 years (n=55654) at 138 institutions. We characterized substance use patterns and used multinomial regression to model adjusted odds of past 30-day ECIG use type [no substance use (reference); sole e-cigarette use; e-cigarette use and other substance use (ECIG+ use); no e-cigarette use but other substance use] by mental health characteristics, past 12-month diagnosis/treatment and psychological distress, individual characteristics, and college characteristics. RESULTS: Alcohol was the most prevalent substance (58%) used, followed by cannabis (23%) and e-cigarettes (15%). Nearly all (95%) students who used e-cigarettes reported using another substance. Adjusted odds of ECIG+ use (vs no substance use) were higher among students with past 12-month mental health diagnosis/treatment (AOR=1.5; 95% CI: 1.4-1.6) and higher psychological distress (AOR=1.1; 95% CI: 1.1-1.2). Other characteristics significantly associated with ECIG+ use included gender identity, sexual orientation, race and ethnicity, self-rated health, year in school, cumulative grade average, fraternity/sorority membership, and current residence. CONCLUSIONS: Most students who used e-cigarettes also reported other substance use, and this pattern of use was associated with poorer mental health outcomes than no substance use. Clarifying the relationship between mental health and ECIG+ use may enhance health interventions for college students.

Unmet needs and harm reduction preferences of syringe services program participants: differences by co-use of illicit opioids and methamphetamine.

BACKGROUND: The current fourth wave of the United States opioid overdose epidemic is characterized by the co-use of opioids and stimulants, including illicit opioids and methamphetamine. The co-use of these two drugs, known as "goofballing," is associated with higher risk for several adverse outcomes, including more frequent injections, greater health risks, and higher morbidity. Considering these differences, this unique subpopulation of people who inject drugs (PWID) may also have unique unmet needs and harm reduction preferences. METHODS: We collected self-reported data from participants (N = 50) of a syringe services program (SSP), including basic needs and harm reduction preferences. Using bivariate analyses, we examined differences between SSP participants who do and do not co-use illicit opioids and methamphetamine. Co-use was defined as reporting the use of both drugs, which may or may not have been used simultaneously. RESULTS: In the overall sample, the mean level of need was highest for bus passes or other transportation, a person who can help you get the services you need, medication for opioid use disorder, and a job or job training. Additionally, all participants reported being either interested or very interested in fentanyl test strips, safe consumption sites, delivery of syringe service supplies, and delivery of naloxone. Those who endorsed co-use had a greater need for food, healthcare, substance use disorder treatment, a support person to help them access needed services, and bus passes or transportation. CONCLUSIONS: Unmet needs were prevalent, and the desire for more harm reduction services was high among these PWID. Results also suggest people who co-use illicit opioids and methamphetamine may have the greatest unmet needs and desire for additional harm reduction services.

Depression screening outcomes among adolescents, young adults, and adults reporting past 30-day tobacco and cannabis use.

BACKGROUND: Few studies examine the relationship between depression and use of specific tobacco and/or cannabis products among adolescents, young adults, and adults. We determined whether the odds of depression are greater among those who used specific tobacco and/or cannabis products and among co-users of tobacco and cannabis. METHOD: Cross-sectional online survey of a national convenience sample of 13-40-year-olds (N = 6,038). The survey included depression screening and past 30-day use of specific tobacco and cannabis products (cigarettes; e-cigarettes, vaped cannabis, little cigars, cigarillos, cigars, hookah, chewing tobacco, smoked cannabis, edible cannabis, blunts). Analyses correspond to the total sample, and 13-17-, 18-24-, and 25-40-year-olds. RESULTS: Among 5,281 individuals who responded to the depression screener and nine product use questions, 1,803 (34.1 %) reported co-use of at least one tobacco product and one cannabis product in the past 30 days. Past 30-day co-use was associated with higher likelihood of screening positive for depression compared to past 30-day use of tobacco-only (aOR = 1.32, 1.06-1.65; 0.006) or cannabis-only (aOR = 1.94, 1.28-2.94; <0.001). Screening positive for depression was more likely among those who reported past 30-day use of e-cigarettes (aOR = 1.56; 1.35-1.80; <0.001), cigarettes (aOR = 1.24, 1.04-1.48; 0.016), chewed tobacco (aOR = 1.91, 1.51-2.42; <0.001), and blunts (aOR = 1.22, 1.00-1.48; 0.053) compared to those who did not report past 30-day use of these products. Among the 2,223 individuals who screened positive for depression, the most used two-product combination was nicotine e-cigarettes and smoked cannabis (614 individuals, 27.6 %). CONCLUSIONS: Screening positive for depression was more likely among past 30-day co-users versus past 30-day users of tobacco-only or cannabis-only. Findings suggest that prevention programs for depression and substance use address tobacco and cannabis co-use.

Reasons for multiple tobacco product and cannabis co-use among Texas young adults.

OBJECTIVE: This study examines differences in reasons for e-cigarette, cigarette, and cannabis use across exclusive, dual, co-, and poly co-users. METHODS: Participants were 645 young adults who reported past 30-day (P30D) use of e-cigarettes, cigarettes, or cannabis at wave 14 (Fall, 2021) of the Texas Adolescent Tobacco Marketing and Surveillance System (TATAMS). Exclusive users reported P30D use of one product, dual users reported P30D use of e-cigarettes and cigarettes, co-users reported use of cannabis and one tobacco product, and poly co-users reported P30D use of all three products. Participants were asked if they agreed with a series of reasons for using their respective products. Multinomial logistic regression analyses were conducted to examine associations between reasons for use and pattern of use, controlling for sex, race/ethnicity, and lifetime product use. RESULTS: 26.36 % of P30D users reported cannabis and tobacco use. Poly co-users were more likely to report using e-cigarettes because their friends do than e-cigarette co-users (aRRR = 2.64; 95 %CI = 1.19-5.83) and dual tobacco users (aRRR = 5.11; 95 %CI = 1.73-15.12). Poly co-users were more likely to smoke cigarettes while drinking alcohol (aRRR = 4.68; 95 %CI = 1.06-20.72) or to experience a pleasurable buzz (aRRR = 5.48; 95 %CI = 1.62-18.57) than exclusive cigarette users. Poly co-users more often reported using cannabis for taste (aRRR = 3.13; 95 %CI = 1.51-6.51), because their friends use it (aRRR = 2.19; 95 %CI = 1.08-4.42), and while drinking alcohol (aRRR = 2.13; 95 %CI = 1.03-4.41) than exclusive cannabis users. CONCLUSIONS: Given that reasons for use differ significantly among types of multiple product users and exclusive users, interventions should be tailored to address the specific tobacco and cannabis use practices of young adults.

Predicting Time to Return to Cannabis Use After a Cessation Attempt: Impact of Cumulated Exposure to Nicotine-Containing Products.

Objective: Cannabis is frequently co-used with tobacco/nicotine products, especially among young adults. Little is known about the effects of this co-use on cannabis cessation outcomes. Within a sample of young adults using cannabis frequently (current use of ≥5 days/week in the past 3 months), this study aimed to (a) document sources of exposure to tobacco/nicotine products, whether used simultaneously with cannabis or on different occasions, (b) examine if the level of cumulated exposure to tobacco/nicotine (self-reported or from biochemical testing) could predict time to cannabis lapse during a cannabis abstinence period, and (c) explore the relationship between nicotine/tobacco exposure and time to cannabis lapse according to tobacco cigarette smoking status. Method: Urine cotinine measures and self-reported data on use of different tobacco/nicotine products, collected from 32 participants (aged 19 to 23), were analyzed to predict time to lapse during a 2-week period of attempted abstinence from cannabis, controlling for cannabis dependence and sex. Results: Half of participants (56.3%) used at least one tobacco/nicotine product. Higher urine cotinine, representing higher cumulated tobacco/nicotine exposure, was related to a higher risk of lapsing (Hazard Ratio [HR] = 1.64; 95%CI [1.04, 2.58]). The risk of lapsing was even higher ([HR] = 3.46; 95%CI [1.17, 10.25]) among heavily tobacco/nicotine exposed (>600 ng/mL, urine cotinine) participants than among unexposed (<50 ng/mL) or lightly/moderately exposed (50-600 ng/mL) participants. Among those smoking cigarettes (solely or in combination with other products), there was no relation between cotinine level and time to lapse, likely due to a reduced variability in abstinence probability and a high likelihood of lapse observed for higher cotinine levels, mainly achieved by cigarette use. Conclusions: With a rapidly changing landscape of tobacco/nicotine use, our results underscore the need to consider all sources of tobacco/nicotine exposure to fully understand the specific and cumulative contributions of tobacco/nicotine to cannabis cessation outcomes.

Tobacco use and heavy episodic drinking among persons aged 18-69 years in Bolivia in 2019.

OBJECTIVES: The aim of this study was to estimate the prevalence and sociodemographic factors associated with tobacco use and heavy episodic drinking (TUHED), current tobacco use only (TU), and current heavy episodic drinking only (HED) among people 18-69 years in Bolivia in 2019. STUDY DESIGN: Cross-sectional study. METHODS: The analysis used cross-sectional data from Bolivia's STEPS 2019 survey; 4472 individuals answered questions about substance use and socio-demographic information. RESULTS: The sample included 50.2% women and 49.8% men, 52.1% had secondary or higher education, 48.6% were Mestizo and 28.0% Quechua. The prevalence of TUHD was 6.0% (10.5% for men, 1.6% for women), TU 12.2% (20.0% for men, 4.4% for women), and HED 11.2% (13.4% for men and 9.1% for women). Male sex increased the risk of TU, HED and TUHED and belonging to the Amara ethnic group decreased the risk of TU and TUHED. Higher education was increased the odds of HED and among women of TUHED. Urban residence increased the risk of TUHED and among women of HED. For women, unemployment was associated with TU and marriage or cohabitation was inversely associated with TU, and for men, belonging to another ethnic group (such as Castellano or Tacana) increased the risk of TU and TUHED. CONCLUSION: More than 10% of the general adult population in Bolivia participated in TU and HED, and among men in TUHED. Various factors associated with the different categories of substance use were identified.

Alcohol and cannabis use and co-use among Whites and Hispanics on and off the U.S./Mexico border in California.

This paper examines self-reported rates of drinking and cannabis use and co-use among White and Hispanic adults randomly selected in four counties in California: Imperial on the border; and Kern, Tulare, and Madera in California's Central Valley. Co-use was significantly higher among the U.S. born than among those born abroad, and in the Central Valley than on the border. Co-users were heavier drinkers, had higher rates of alcohol use disorder, other alcohol problems, and a positive history of illicit drug use than drinkers only.

Interactive effects of alcohol and cannabis quantities in the prediction of same-day negative consequences among young adults.

BACKGROUND: Simultaneous alcohol and cannabis use is common, but observational studies examining negative consequences of simultaneous use have rarely considered dose-related interactions between alcohol and cannabis. This study examined interactions between quantities of cannabis and alcohol consumed in predicting negative consequences on simultaneous use days. METHODS: Young adults (N = 151; 64% female; 62% White) reporting recent simultaneous use and at least weekly alcohol and cannabis use completed 21 daily, smartphone-based surveys assessing previous day quantities of cannabis and alcohol used, types of cannabis used (flower, concentrates, edibles), and negative substance-related consequences. Multilevel models examined: (1) whether negative consequences differed within-person across simultaneous use days and single-substance use days; and (2) whether quantities of alcohol and cannabis consumed on simultaneous use days interacted, within-person, to predict negative consequences. We focused on quantities of cannabis flower (grams) in primary analyses and explored quantities of other forms of cannabis (concentrates, edibles) in supplementary analyses. RESULTS: Participants reported fewer negative consequences on alcohol-only (243 observations) and cannabis-only (713 observations) days than they did on simultaneous use days (429 observations). On simultaneous use days involving cannabis flower use (313 observations across 81 participants), the within-person association between number of standard drinks and negative consequences was weaker on days during which larger (vs. smaller) amounts of cannabis flower were consumed. Inspection of simple slopes revealed that decreased alcohol use was associated with less of a decline in negative consequences when combined with relatively greater amounts of cannabis flower. CONCLUSIONS: Although simultaneous use was associated with more negative consequences than alcohol-only and cannabis-only use, negative consequences on simultaneous use days varied as a function of the interaction between alcohol and cannabis quantities. As findings suggest that using larger amounts of cannabis may attenuate declines in negative consequences associated with lighter drinking, interventions for higher-risk simultaneous use patterns may benefit from a focus on quantities of both alcohol and cannabis.

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

INTRODUCTION: Despite evidence suggesting deleterious effects of cannabis and nicotine tobacco product (NTP) use on white matter integrity, there have been limited studies examining white matter integrity among users of both cannabis and nicotine. Further, updated white matter methodology provides opportunities to investigate use patterns on neurite orientation dispersion and density (NODDI) indices and subtle tissue changes related to the intra- and extra-neurite compartment. We aimed to investigate how cannabis and NTP use among adolescents and young adults interacts to impact the white matter integrity microstructure. MATERIALS AND METHODS: A total of 221 participants between the ages of 16 and 22 completed the Customary Drinking and Drug Use Record (CDDR) to measure substance use, and underwent a magnetic resonance imaging (MRI) session. Participants were divided into NTP-control and NTP groupings and cannabis-control and cannabis groupings (≥26 NTP/cannabis uses in past 6 months). Tract-Based Spatial Statistics (TBSS) and two-way between-subjects ANOVA investigated the effects of NTP use group, cannabis use group, and their interaction on fractional anisotropy (FA) and NODDI indices while controlling for age and biological sex. RESULTS: NTP use was associated with decreased FA values and increased orientation dispersion in the left anterior capsule. There were no significant effects of cannabis use or the interaction of NTP and cannabis use on white matter outcomes. DISCUSSION: NTP use was associated with altered white matter integrity in an adolescent and young adult sample. Findings suggest that NTP-associated alterations may be linked to altered fiber tract geometry and dispersed neurite structures versus myelination, as well as differential effects of NTP and cannabis use on white matter structure. Future work is needed to investigate how altered white matter is related to downstream behavioral effects from NTP use.

Alcohol and cannabis co-use: Receptiveness to treatments and application to intervention planning.

Given the prevalence of alcohol and cannabis co-use among college students, prevention for co-use is crucial. We examined hypothetical receptiveness to substance-specific interventions among students who reported co-use. Students who use alcohol and cannabis were more receptive to alcohol interventions than cannabis interventions. Campus prevention experts should consider offering evidence-based alcohol-focused interventions as a potential pathway for decreasing substance use among college students who engage in co-use.

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.