Identifying risk profiles for marijuana vaping among U.S. young adults by recreational marijuana legalization status: A machine learning approach

Longitudinal Transitions Between Use of Combustible, Noncombustible, and Multiple Cannabis Products From Adolescence to Young Adulthood and Intersections With Nicotine Use

Understanding transitions across use of different types of cannabis products and multiple cannabis products and how they intersect with nicotine use in young people can inform etiology and prevention. In this study, we examined transitions across use of combustible and noncombustible forms of cannabis and multiple types of cannabis from adolescence to young adulthood and the role of nicotine use in transitions. In a Southern California longitudinal cohort study (n = 3,298; baseline mean age = 16.1 (standard deviation, 0.4) years) with 9 semiannual survey waves (2015-2021), we used Markov multistate transition modeling to estimate short-term (2-wave) and long-term (9-wave) probabilities of transition across 5 cannabis use states: never use of any product, prior use with no past-6-month (P6M) use of any product, and P6M use of exclusively noncombustible products, exclusively combustible products, and multiple (noncombustible + combustible) products. Sizable transition probabilities from prior and exclusive P6M noncombustible or combustible cannabis use to P6M poly-cannabis-product use were observed in short-term (10.7%-38.9%) and long-term (43.4%-43.8%) analyses. P6M nicotine use increased risk of transitioning from never and prior use to exclusive P6M noncombustible and combustible cannabis use. Cannabis use in any form, even temporary use, during midadolescence may often be followed by poly-cannabis-product use. Nicotine use may amplify the probability of future cannabis use onset or recurrence.

Systematic Review and Meta-Analysis: Medical and Recreational Cannabis Legalization and Cannabis Use Among Youth in the United States

OBJECTIVE

Dramatic changes in state-level cannabis laws (CL) over the past 25 years have shifted societal beliefs throughout the United States, with unknown implications for youth. In the present study, we conducted an updated systematic review and meta-analysis examining estimated effects of medical cannabis legalization (MCL) and recreational cannabis legalization (RCL) on past-month cannabis use among US youth.

METHOD

A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, followed by a subsequent meta-analysis investigating the associations between state-level cannabis laws (ie, MCL vs non-MCL, and RCL vs non-RCL) and past-month cannabis use prevalence among US adolescents and young adults. Supplemental analyses examined age-group effects and design-related factors.

RESULTS

Our search identified 4,604 citations, 34 and 30 of which were included in qualitative and quantitative analyses, respectively. Meta-analysis of MCL studies identified no significant association between MCL and change in past-month youth cannabis use (odds ratio [OR] = 0.981, 95% CI = 0.960, 1.003). Meta-analysis of RCL studies showed significantly increased odds of past-month cannabis use (OR = 1.134, 95% CI = 1.116-1.153). Meta-analysis of more recent studies, however, showed a significantly increased odds of past-month cannabis use among both adolescents and young adults (OR = 1.089, 95% CI = 1.015,1.169, and OR = 1.221, 95% CI = 1.188,1.255, respectively).

CONCLUSION

Cannabis legalization has complex and heterogenous effects on youth use that may differ across law types. Our meta-analytic results showed modest positive effects of RCL on past-month cannabis use (more so in young adults than in adolescents) and minimal effects of MCL on these outcomes in US youth. Given the shift toward recreational legalization, additional focus on RCL effects is warranted.

The Impact of Recreational Cannabis Legalization on Cannabis Use and Associated Outcomes: A Systematic Review

Background

Recreational cannabis legalization has become more prevalent over the past decade, increasing the need to understand its impact on downstream health-related outcomes. Although prior reviews have broadly summarized research on cannabis liberalization policies (including decriminalization and medical legalization), directed efforts are needed to synthesize the more recent research that focuses on recreational cannabis legalization specifically. Thus, the current review summarizes existing studies using longitudinal designs to evaluate impacts of recreational cannabis legalization on cannabis use and related outcomes.

Method

A comprehensive bibliographic search strategy revealed 61 studies published from 2016 to 2022 that met criteria for inclusion. The studies were predominantly from the United States (66.2%) and primarily utilized self-report data (for cannabis use and attitudes) or administrative data (for health-related, driving, and crime outcomes).

Results

Five main categories of outcomes were identified through the review: cannabis and other substance use, attitudes toward cannabis, health-care utilization, driving-related outcomes, and crime-related outcomes. The extant literature revealed mixed findings, including some evidence of negative consequences of legalization (such as increased young adult use, cannabis-related healthcare visits, and impaired driving) and some evidence for minimal impacts (such as little change in adolescent cannabis use rates, substance use rates, and mixed evidence for changes in cannabis-related attitudes).

Conclusions

Overall, the existing literature reveals a number of negative consequences of legalization, although the findings are mixed and generally do not suggest large magnitude short-term impacts. The review highlights the need for more systematic investigation, particularly across a greater diversity of geographic regions.

Within-person associations of escalated electronic nicotine delivery systems use with cigarette, alcohol, marijuana and drug use behaviors among US young adults

AIMS

Most extant evidence has addressed between-person differences, short-term or cross-sectional associations of electronic nicotine delivery systems (ENDS) use with other substance use, the majority focusing on current rather than escalated use. The present study aimed to examine within-person changes in escalated ENDS use and their associations with individual and combined substance use over a 6-year period.

DESIGN, SETTING AND PARTICIPANTS

This study used a longitudinal cohort design with US young adults. A generalized linear mixed-model approach was employed to fit a series of weighted logistic regression models. Data were drawn from waves 1-5 of the Population Assessment of Tobacco and Health (PATH) study in the United States. Of the 9110 young adults at baseline, aged 18-24 years, a total of 5042 individuals had matched data across all five waves of assessments.

MEASUREMENTS

Escalated ENDS use was computed by subtracting the number of days of ENDS use within the past 30 days at wave w - 1 from that at wave w and coded as 1 = escalated, if the value was greater than zero (otherwise, coded as 0 = not escalated).

FINDINGS

Escalated ENDS use gradually decreased over time, with the lowest prevalence at wave 4 (4.0%) but sharply increasing at wave 5 (8.4%). Escalated ENDS use was associated with increased odds of using each substance (binge drinking, marijuana use, marijuana vaping, prescription and illicit drugs) and different combinations of polysubstance use between cigarette smoking, binge drinking and marijuana use (Ps < 0.05). In addition, sweet/fruit flavor use (versus menthol/mint) was associated with increased likelihood of reporting co-use of cigarettes and marijuana.

CONCLUSIONS

In the United States, the prevalence of young adults using electronic nicotine delivery systems appears to have increased steadily between 2013 and 2019, although the rate of increase may have started to accelerate in recent years. Escalated electronic nicotine delivery systems use and time-lagged established electronic nicotine delivery systems use appear to be prospectively associated with individual and combined substance use, particularly between cigarettes, alcohol and marijuana. Among established electronic nicotine delivery systems users, sweet/fruit flavor appears to be associated with increased risk of co-using cigarettes and marijuana.