Using Existing Data to Advance Knowledge About Adolescent and Emerging Adult Marijuana Use in the Context of Changes in Marijuana Policies

Dealing with Zeros: Adolescent Drug Use, Perceived Disapproval, and Perceived Harm

Because studies examining youth drug use often have data with a high proportion of zeros, they often do not meet the assumptions for univariate or linear regression analyses that are typically used. We demonstrate the use of zero-inflated negative binomial regression models to address excessive zeros in drug use frequency on perceptions of disapproval and perceived harm among middle and high school students (N = 522). We found that perceptions of parent disapproval were a better predictor of marijuana use (p = .01) than peer disapproval. Perceived harm was related to marijuana use (p = .04). Researchers should consider using zero-inflated negative binomial regression models when examining youth drug use.

Substance-Specific Risk Factors for Cannabis and Alcohol Use Among Young Adults Following Implementation of Nonmedical Cannabis Legalization

Laws regarding cannabis are rapidly changing in the USA as more states legalize nonmedical cannabis for adults aged 21 and older. Previous research has examined whether legalization has led to an increase in cannabis use as well as the use of other substances. The current study examined changes in cannabis- and alcohol-specific risk factors following legalization of nonmedical cannabis. We used 6 years of annual cross-sectional data (2014-2019) from 12,951 young adults age 18 to 25 who resided in Washington state. Risk factors examined include perceiving that use was common among same-age peers, believing use was acceptable, having easy access, and low perceived physical and psychological harm from use. Logistic regression models estimated annual rate of increase in these risk factors. All cannabis-specific risk factors increased among those aged 21+ (range of ORs for annual rate of change: 1.07-1.31) while significant increase in cannabis-related risk factors among those under age 21 was limited to perceptions of cannabis use being common (medical use: OR=1.08, 95% CI: 1.03, 1.12; nonmedical use: OR=1.13, 95% CI: 1.08, 1.18) and low perceived physical harm of occasional use (OR=1.08, 95% CI: 1.03, 1.13). Although descriptive norms for past-year use of alcohol among those aged 21+ increased (OR = 1.09, 95% CI: 1.02, 1.17), other risk factors for alcohol did not change significantly or, in the case of low perceived physical and psychological harm, decreased among both those under age 21 and those aged 21+ (range of ORs = 0.90-0.94). Given these findings show an increase in cannabis-specific risk factors since legalization was implemented, particularly among those young adults aged 21+, preventive interventions correcting risk misperceptions and related risk factors among young adults aged 21+ may prove efficacious in reducing use and resultant negative consequences.

Racial/Ethnic Differences in Vaping Product Use among Youth: A State-Level Analysis

National data suggest that non-Hispanic, White youth engage in electronic cigarette (e-cigarette) use at the highest rates. These results are not likely to be mirrored across regional contexts. State-representative data from Utah in 2019 (N = 58,689) were used to estimate the odds of lifetime and past 30-day vaping across seven racial/ethnic categories. Youth in grades 8, 10, and 12 (mean age 15.2; 52% female) self-reported race/ethnicity and vaping product use history, including e-cigarettes, vape pens, or mods. A Cox proportional hazards model estimated the cumulative probabilities for initiating vaping product use. The results indicated that American Indian or Alaskan Native, Black or African American, Hispanic/Latino, Multiracial, and Native Hawaiian or other Pacific Islander youth had significantly higher odds of both lifetime and past 30-day vaping compared to non-Hispanic White youth. The results showed significant variation in the cumulative probability of initiation by race/ethnicity, with Hispanic/Latino youth reporting the highest odds of initiation at each age. The regional patterns of vaping across racial/ethnic groups may not mirror national trends. State- and community-level data should be used to inform efforts to reduce e-cigarette use and promote health equity among youth.

"What Do You Consider Use?" Perspectives of Black Youth on Cannabis Use

PURPOSE

Adolescent health surveillance systems are critical for understanding patterns of cannabis use; however, their limitations underscore the need for studies that generate new insights, particularly from individuals who are most impacted by negative outcomes. Our objectives were to learn about youths' cannabis use and their perceptions of their peers' cannabis use; their perspectives about trajectories of cannabis use over time and factors that influence trajectories; and perceived risks and benefits associated with cannabis use.

METHODS

A group model building approach was used to gather data about cannabis use from a sample of urban, Black youth. Information about participants' cannabis use was assessed on eligibility screener, enrollment survey, and through structured activities over the course of four group model building workshops.

RESULTS

Participants [(n = 20) mean age 18; 35% male and 95% Black] exclusively used the terms weed and blunts for cannabis. Youth who consume peers' blunts would not characterize themselves as cannabis users. Collectively, youth estimated the majority of Baltimore youth used cannabis by age 16 and that most used daily. Youth described cannabis as more beneficial than harmful. There were no gender differences in prevalence of use, but there were gender dynamics to shared use.

DISCUSSION

Participatory research with urban, Black youth suggests youths' perceptions are misaligned with the ways that researchers conceptualize cannabis use. To better understand the scope of youth cannabis use and its harms, it is critical to leverage input from youth with lived experience to ensure survey tools adequately capture the way youth see themselves using cannabis.

Long-Term Impact of Medical Marijuana Laws on the Burden of Cannabis Use Disorders in US Male and Female Adolescents and Young Adults

Deregulation of cannabis use has raised concerns regarding its potential effects on health, particularly in adolescents and young adults. Here, we extracted data from the Global Burden of Disease database to estimate the long-term effect (> 5 years) of medical marijuana laws (MML) on 2019 cannabis use disorders Disability Adjusted Life Years (2019 CUD DALYs) in US male and female adolescents (15-19 years old) and young adults (20-24 years old). Socio-cultural, demographic and economic characteristics were used as baseline covariates. To improve the robustness of estimation, we took advantage of machine learning techniques. We found no significant effect of MML on 2019 CUD DALYS in each of our four age/sex groups. Estimates from a marginal structural model taking into account age and sex strata in the same model were also non-significant. Our findings suggest that MML may have a negligible effect (if any) on cannabis use disorders in this population group.

Substance-Specific Risk Factors among Young Adults: Potential Prevention Targets across Cannabis-Permissive Environments

PURPOSE

This study examined levels of substance-specific risk factors such as perception of harm from substance use among young adults in a range of cannabis-permissive environments. The main objective was to inform future preventive interventions aimed at reducing cannabis use in the context of increasingly permissive environments.

METHODS

Data came from the Community Youth Development Study (CYDS) collected in 2016 when participants were about 23 years old (n = 1,722 participants residing in 46 U.S. states). Young adults self-reported their perceptions about the harms related to cannabis, alcohol, and cigarette use; attitudes about and ease of access to cannabis and other substances; and perceived wrongfulness and social acceptability of cannabis, alcohol, and cigarette use and of selling of cannabis and other illegal drugs.

RESULTS

Young adults in more permissive cannabis contexts reported higher levels of all cannabis-specific risk factors (e.g., greater access to and more favorable attitudes about cannabis use), except for perception of harm from regular cannabis use. However, permissiveness of the cannabis environment was not associated with heightened levels of risk factors for other substance use (such as alcohol, cigarettes, and opioids).

CONCLUSIONS

Future preventive interventions for young adults living in more permissive cannabis contexts may need to focus on cannabis-specific risk factors in particular and go beyond considerations of harm from regular use. Future studies should replicate these findings with other samples.

Trends in Alcohol, Cigarette, E-Cigarette, and Nonprescribed Pain Reliever Use Among Young Adults in Washington State After Legalization of Nonmedical Cannabis

PURPOSE

Liberalization of cannabis laws may be accompanied by changes in the use of substances other than cannabis and changes in associations of cannabis use with other types of substance use. This study assessed (1) trends in alcohol, nicotine, and nonprescribed pain reliever use and (2) changes in associations of cannabis use with these other substances among young adults in Washington State after nonmedical cannabis legalization.

METHODS

Regression models stratified by age (18-20 vs. 21-25) were used to analyze six annual waves of cross-sectional survey data from a statewide sample from 2014 through 2019 (N = 12,694).

RESULTS

Prevalence of past-month alcohol use, heavy episodic drinking (HED), and cigarette use and prevalence of past-year pain reliever misuse decreased, while the prevalence of past-month e-cigarette use increased since 2016 (the first year assessed). Across years and age groups, the prevalence of substance use other than cannabis was higher among occasional and frequent cannabis users compared to cannabis nonusers. However, associations between both occasional (1-19 days in the prior month) and frequent (20+ days) cannabis use and pain reliever misuse and between frequent cannabis use and HED weakened over time among individuals ages 21-25.

DISCUSSION

Contrary to concerns about spillover effects, implementation of legalized nonmedical cannabis coincided with decreases in alcohol and cigarette use and pain reliever misuse. The weakening association of cannabis use with the use of other substances among individuals ages 21-25 requires further research but may suggest increased importance of cannabis-specific prevention and treatment efforts.

A Systematic Review and Narrative Synthesis of the Evolution of Adolescent and Young Adult Cannabis Consumption Before and After Legalization

PURPOSE

To systematically review evidence assessing the evolution of cannabis consumption before and after the implementation of non-medical cannabis legislation.

METHODS

MEDLINE, PubMED, PsycINFO, Scopus, and Web of Science were systematically searched for studies that examined change in cannabis consumption before and after nonmedical cannabis legislation. Data were tabulated by study design, levels of consumption, and individual subgroups. Data were analyzed using a narrative synthesis approach, considering study quality.

RESULTS

32 studies were included (11 higher quality and 21 lower quality). 40% of higher quality evidence supported an increase in postlegalization consumption (55% did not report a change and 5% reported a decrease). The increase was most evident for young adults (42% of higher quality evidence) and in the consumption in the past month (37% of higher quality evidence). There was limited supporting evidence for new users having grown in response to legalization. Based on subgroup analysis, the increase in postlegalization consumption was higher among women and those who engage in binge-drinking.

CONCLUSIONS

Higher quality evidence suggests an increase in adolescent past-month consumption of cannabis following legalization in several geographical jurisdictions. Consumption evolution prelegalization and postlegalization differed by age group and for young women and for binge drinkers. Consumption evolution differences suggest a variety of strategies might be required in efforts to lower public health impacts of cannabis consumption following legalization.

Marijuana Policy Bundles in the American States Over Time and Their Impact on the Use of Marijuana and Other Drugs

American states have used different approaches in adoption of cannabis policies and continue to modify those policies after approval. States also differ in how long it takes to implement such policies, and this influences the availability of legal marijuana. Such policy differences and implementation timelines could influence usage of marijuana and other illicit drugs by adolescents, young adults, and older adults. We develop an original coding scheme for marijuana legalization policies by classifying policy bundles characterized by three views of marijuana: as a pharmaceutical; as a permissive drug, or as a state fiscal revenue source. We test the impact of state legal marijuana policy characteristics on age group rates of marijuana use with panel regression models including control variables and fixed effects for 2000-2019. This design moves beyond a dichotomous construct of marijuana legalization and accounts for the dynamic adaptation of policies beyond their initial adoption. States with a higher pharmaceutical score experienced lower marijuana usage rates for adolescents and young adults while states with a permissive approach or fiscal approach experienced higher rates of marijuana use for all age groups. We find no consistent spillover effect of the pharmaceutical or permissive marijuana policy bundles on other illicit drug use for any age group, but fiscal bundles show some association with greater illicit drug use for adults. These more nuanced measures better reflect state policies as implemented and provide more clarity of the policy impact on target populations' marijuana usage.

Association of Cannabis Use-Related Predictor Variables and Self-Reported Psychotic Disorders: U.S. Adults, 2001-2002 and 2012-2013

OBJECTIVE

The authors sought to determine the association of cannabis indicators with self-reported psychotic disorders in the U.S. general population.

METHODS

Participants were from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; 2001-2002; N=43,093) and NESARC-III (2012-2013; N=36,309). Logistic regression was used to estimate standardized prevalences of past-year self-reported psychotic disorders within each survey and to evaluate the association of past-year self-reported psychotic disorders with indicators of nonmedical cannabis use (any use; frequent use [at least three times/week], daily/near-daily use, and DSM-IV cannabis use disorder) compared with those with no past-year nonmedical cannabis use. Whether the strength of associations differed between surveys was indicated by difference-in-difference tests (between-survey contrasts) and ratios of odds ratios between surveys.

RESULTS

Self-reported psychotic disorders were significantly more prevalent among participants with any nonmedical cannabis use than those without (2001-2002: 1.65% compared with 0.27%; 2012-2013: 1.89% compared with 0.68%). In 2001-2002, self-reported psychotic disorders were unrelated to either frequent use or daily/near-daily use. However, in 2012 - 2013, compared with nonusers, self-reported psychotic disorders were more common among participants with frequent use and those with daily/near-daily nonmedical cannabis use (2012-2013: 2.79% and 2.52%, respectively, compared with 0.68% among nonusers). Self-reported psychotic disorders were significantly more prevalent among participants with cannabis use disorder than nonusers in both surveys (2001-2002: 2.55% compared with 0.27%; 2012 - 2013: 3.38% compared with 0.68%). The strength of these associations did not change over time.

CONCLUSIONS

Data from the U.S. general population, especially more recent data, suggest associations between self-reported psychotic disorder and frequent nonmedical cannabis use and cannabis use disorder. Clinicians and policy makers should consider these relationships when monitoring patients and formulating programs.

Simultaneous use of marijuana and alcohol: Potential prevention targets among young adults who use alcohol

Simultaneous alcohol and marijuana use (SAM) such that their effects overlap has emerged as a behavior that is riskier than using either substance separately. It has been associated with high-risk binge drinking and driving while intoxicated during young adulthood, and it has been demonstrated to cause greater physical and mental impairment than use of alcohol or marijuana separately. To identify intervention and prevention targets specific to SAM, we examined the relationships between alcohol- and marijuana-specific beliefs and attitudes (risk factors) and self-reported SAM compared to non-simultaneous co-use (CAM) and alcohol use only in the past 30 days in a sample of young adults (n = 1,023, mean age = 23.17; SD = 0.43). Of those who reported drinking alcohol in the past 30 days, 20.7% reported SAM, 12.6% reported CAM, and 66.6% reported using only alcohol. Results from multinomial logistic regression analyses indicated that some marijuana-specific risk factors (e.g., belief that it is not at all wrong for someone their age to use marijuana) differentiated SAM or CAM from alcohol use only, but alcohol-specific risk factors generally did not. However, the perceptions that parents approved of their using marijuana or frequently drinking heavily were associated with a greater likelihood of SAM compared to CAM (OR ranged from 2.25 to 3.53). Findings point to the salience of individuals' attitudes and beliefs around marijuana use and their perception of parental approval of heavy drinking and marijuana use as potential targets for prevention programs targeting risk reduction among young adults.

Dual trajectories of cannabis and alcohol use among young adults in a state with legal nonmedical cannabis

BACKGROUND

Understanding the nature of the association between cannabis and alcohol use within individuals over time in the era of legalized cannabis is of crucial importance for assessing the public health consequences of increasing cannabis use. An important unanswered question is whether cannabis and alcohol use substitute for one another. Specifically, is greater use of one substance associated with less use of the other substance (i.e., a negative association) or are the substances complementary and their association positive?

METHODS

We used 24 consecutive months of data on a young adult sample (n = 774; 56% female, age 18-25 during the study) who drank alcohol in the year prior to enrollment. The sample was recruited in Washington State in 2015/2016 (after legalization of nonmedical cannabis) using media advertisements and community flyers and outreach. Using parallel process latent growth curve models, we assessed three types of association between cannabis and alcohol use across the 24-month period: (1) an association between average levels of cannabis and alcohol use; (2) an association between rates of change in cannabis and alcohol use; and (3) correlations between shorter-term deviations/fluctuations off of longer-term trajectories of level and change in cannabis and alcohol use.

RESULTS

We found a positive association between the average frequency of cannabis and alcohol use; individuals who used cannabis more frequently on average also drank alcohol more frequently on average. Change over time in cannabis use was positively associated with change in alcohol use. There was also a contemporaneous positive association between fluctuations in cannabis and alcohol use.

CONCLUSIONS

Overall, we found no evidence of substitution. Rather, the results suggest a complementary relationship between cannabis and alcohol use, such that the use of cannabis and alcohol rises and falls together.

State Medical Marijuana Laws and Initiation of Cigarettes among Adolescents in the U.S., 1991-2015

Objective

Although cigarette use has declined among adolescents, marijuana use has increased in subgroups of this population. The association between medical marijuana laws (MMLs) and cigarette initiation among adolescents, however, needs further examination. We investigated the association between MMLs and age of cigarette initiation and stratified findings by gender, race/ethnicity, and state dispensary status.

Method

Data were from N=939,725 adolescents in 9^th-12^th grade living in 46 states who participated in the Youth Risk Behavior Surveillance System between 1991-2015. Participants were asked the age they first smoked a cigarette and other sociodemographic characteristics. States were categorized as MML states if they had legalized marijuana for medicinal purposes by 2015. We used a difference-in-difference methodology and logistic regressions to assess the relationship between MMLs and cigarette initiation.

Results

Our results indicate lower odds of initiating cigarettes, in every age group (8 years old or younger, 9-10, 11-12, 13-14, 15-16, 17 years old or older) in states with MMLs when compared to non-MML states. After stratification, we find lower odds of cigarette initiation in certain age groups by gender, race/ethnicity, and state dispensary status. We report no difference in state MML implementation and age of cigarette initiation among Hispanic adolescents in every age group, and Black adolescents 8 years or younger and 17 years or older.

Conclusions

Cigarette initiation has decreased among adolescents in MML states compared with those in non-MML states. Further research should evaluate how MMLs and recreational marijuana policies are associated with e-cigarette initiation and use.

Medical marijuana laws (MMLs) and dispensary provisions not associated with higher odds of adolescent marijuana or heavy marijuana use: A 46 State Analysis, 1991-2015

Background: States are rapidly moving to reverse marijuana prohibition, most frequently through legalization of medical marijuana laws (MMLs), and there is concern that marijuana legalization may affect adolescent marijuana use. Methods: This natural-experimental study used state Youth Risk Behavior Survey (YRBS) data collected from participants in grades 9-12 from 1991 to 2015 in 46 states (N = 1,091,723). Taking advantage of heterogeneity across states in MML status and MML dispensary design, difference-in-difference estimates compared states with enacted MMLs/dispensaries to non-MML/dispensaries states. Multivariable logistic regression modeling was used to adjust for state and year effects, and student demographics. The main outcome assessed was past 30-day adolescent marijuana use ["any" and "heavy" (≥20)]. Results: In the overall sample, the adjusted odds of adolescents reporting any past 30-day marijuana use was lower in states that enacted MMLs at any time during the study period (OR 0.94, 95% CI 0.89 to 0.99; p < .05), and in states with operational dispensaries in 2015 (OR 0.93, 95% CI 0.88 to 0.99; p < .05). Among grade cohorts, only 9th graders showed a significant effect, with lower odds of use with MML enactment. We found no effects on heavy marijuana use. Conclusions: This study found no evidence between 1991 and 2015 of increases in adolescents reporting past 30-day marijuana use or heavy marijuana use associated with state MML enactment or operational MML dispensaries. In a constantly evolving marijuana policy landscape, continued monitoring of adolescent marijuana use is important for assessing policy effects.

David H, Kosterman R, Bailey JA, Oesterle S, Cambron C, Farrington DP. Applying the Social Development Model in Middle Childhood to Promote Healthy Development: Effects From Primary School Through the 30s and Across Generations

PURPOSE

This paper describes the origins and application of a theory, the social development model (SDM), that seeks to explain causal processes that lead to the development of prosocial and problem behaviors. The SDM was used to guide the development of a multicomponent intervention in middle childhood called Raising Healthy Children (RHC) that seeks to promote prosocial development and prevent problem behaviors. This paper reviews and integrates the tests of the SDM and the impact of RHC. While the original results of both model and intervention tests have been published elsewhere, this paper provides a comprehensive review of these tests. As such this integrative paper provides one of the few examples of the power of theory-driven developmental preventive intervention to understand impact across generations and the power of embedding controlled tests of preventive intervention within longitudinal studies to understand causal mechanisms.

METHODS

Application of the SDM in the RHC intervention was tested in a quasi-experimental trial nested in the Seattle Social Development Project (SSDP). SSDP is a longitudinal study of 808 students who attended 18 public schools in Seattle, WA, and whose parents consented for their participation in longitudinal research when they were in Grade 5 (77% of the eligible population in participating schools). Students assented at each survey administration and consented to longitudinal follow-up when they turned 18. Panel subjects were followed and surveyed 15 times from Grade 5 through age 39, with most completion rates above 90%.

RESULTS

We describe effects of the full multicomponent RHC intervention delivered in Grades 1 through 6 by comparing outcomes of those children assigned to the full RHC intervention condition to controls from middle childhood through age 39. We also report the effects of the full RHC intervention on the firstborn children of participants compared with the firstborn children of controls.

CONCLUSIONS

We discuss use of the theory to guide development and testing of preventive interventions and the utility of nesting intervention tests within longitudinal studies for testing both theory and interventions.

Cannabis attitudes and patterns of use among followers of the Allergy & Asthma Network

BACKGROUND

Cannabis use in patients with allergy/asthma, a high-risk group for adverse effects to cannabis, is unknown.

OBJECTIVE

To determine the patterns of use and attitudes toward cannabis in patients with allergy/asthma.

METHODS

An anonymous online survey on cannabis attitudes and use was conducted through the Adult Allergy & Asthma Network. The Asthma Control Test assessed asthma burden. Cluster analyses determined group phenotypes and factor analyses condensed cannabis subjective effects into similar response patterns.

RESULTS

A total of 88 of 489 respondents (18.0%) currently use cannabis with most at the age of less than 50 years old, of female sex, and of White race. Of the noncannabis users (N = 401), 2.5% reported cannabis allergy. Cluster analysis revealed that a liberal attitude toward cannabis was associated with current cannabis use (P < .001). Among current cannabis users, 40.9% of their physicians inquired on cannabis use; only 37.5% of users wanted to discuss cannabis. In addition, 65.9% used cannabis for medical or medical/recreational purposes. Cannabinoids used were tetrahydrocannabinol (33.0%), cannabidiol (19.3%), or both (47.7%). Smoked and vaped cannabis were reported by 53.4% and 35.2%, respectively. Furthermore, 51 cannabis users (58.0%) reported current asthma with 39.2% uncontrolled; of these, 50% smoked cannabis. Compared with current participants with asthma not using cannabis, those currently using cannabis experienced similar levels of asthma control, quality of life, and frequency of asthma exacerbations. Positive effects were endorsed more than negative effects to cannabis (P < .001). Moreover, 19.3% of cannabis users reported coughing that was associated with smoking cannabis (P < .001).

CONCLUSION

Cannabis was used by less than 20% of the respondents with positive effects more frequent than negative effects. Half of cannabis users with uncontrolled asthma smoke cannabis, but only a minority of the physicians inquire about its use.

Has Cannabis Use Among Youth Increased After Changes in Its Legal Status? A Commentary on Use of Monitoring the Future for Analyses of Changes in State Cannabis Laws

As US states move toward various forms of adult access to cannabis, there has been a great interest in measuring the impact of such changes on adolescent cannabis use. Two recent prominent analyses have used Monitoring the Future (MTF), a nationally representative survey of students, to examine the effects. We compared MTF data for California and for Washington State with other survey data on use by adolescents in those states. In both studies, findings based on MTF were different from those using other larger, state-representative surveys. The discrepancy reflects the high within-state variation in prevalence rates and the small number of schools in MTF state samples. Using the Washington Health Youth Survey, we estimate that after recreational cannabis legalization past 30-day cannabis use prevalence in grade 8 decreased by 22.0%, in grade 10 prevalence decreased by 12.7%, and no effect in grade 12. These trends are consistent with those in states without recreational cannabis laws, suggesting that legalization did not impact adolescent use prevalence. Long-term trends in MTF are consistent with other data, but year-to-year volatility in state-level series undermines the survey's suitability for evaluation of state cannabis policy changes. Survey-based analyses at the state level need to be cross-validated with findings from other data sources. When findings are disparate and methodological rigor is equivalent, analyses of data sources specifically designed to describe state-level phenomena are more credible.