Examination of the Divergence in Trends for Adolescent Marijuana Use and Marijuana-Specific Risk Factors in Washington State

Exploring the relationship of rurality and region: An analysis of adolescent marijuana use in the United States

Marijuana use among adolescents and young adults has increased, however, there is a paucity of research concerning marijuana use among adolescents in rural areas. Current literature holds the assumption that adolescents in rural areas tend to use less marijuana and marijuana associated products compared with youth from urban and suburban areas. However, geographical features may contribute to unique stressors experienced by rural youth, resulting in distinct differences in usage that have been previously unexplored. The purpose of the current study was to explore the relationship between rurality and geographic region by examining patterns of lifetime marijuana use in 12th graders across various geographical backgrounds. Using data from the Monitoring the Future Study database, participants were classified based on rurality (rural, medium suburban/urban, large suburban/urban) and geographic region (Northeast, Midwest, South, West) and data was analyzed to investigate the differences in lifetime marijuana and hash usage. Results demonstrated that rural adolescents in the Northeast and West reported lifetime marijuana and hash product use at the same level as their urban/suburban counterparts; however, there were differences across rurality among Midwest and Southern regions. These results suggest that lifetime marijuana use among rural adolescents is not uniform across geographic regions, indicating that geography should be heavily considered when formulating preventative and educational marijuana programs.

Cannabis cue-reactivity in cannabis use disorder: Diverging evidence in two distinct cannabis cultures

BACKGROUND

Cannabis policies and attitudes play a role in the development and presentation of cannabis use disorder (CUD), but it is unclear how these factors are related to biomarkers of addiction. The current study examined cross-cultural differences in cannabis attitudes, cannabis cue-reactivity in the brain and its associations with cannabis use measures and cannabis attitudes.

DESIGN

Cross-sectional fMRI study.

SETTING

The Netherlands (NL) and Texas (TX), USA.

PARTICIPANTS

104 cannabis users with CUD (44% female; NL-CUD = 54, TX-CUD = 50) and 83 non-using controls (52% female; NL-CON = 50, TX-CON = 33).

MEASUREMENTS

Self-reported positive (perceived benefits) and negative (perceived harms) cannabis attitudes and tactile cannabis cue-reactivity assessed using a 3T MRI scanner.

FINDINGS

While the CUD group overall was more positive and less negative about cannabis and reported higher craving, the TX-CUD group reported significantly more positive and less negative attitudes and less craving than the NL-CUD group. Cannabis cue-reactivity was observed in the CUD group in clusters including the precuneus, lateral occipital cortex, frontal medial cortex, nucleus accumbens, and thalamus. In the TX-CUD group, a positive association was observed between symptom severity and cue-induced craving and cannabis cue-reactivity in precuneus and occipital cortex clusters, while a negative association was observed in the NL-CUD group. In these clusters, individuals with more positive attitudes exhibited a positive association between craving and cue-reactivity and those with less positive attitudes exhibited a negative association. No associations with quantity of use were observed.

CONCLUSIONS

Cue-induced craving might be deferentially associated with cannabis cue-reactivity across distinct cannabis use environments.

Adolescents' Cannabis Knowledge and Risk Perception: A Systematic Review

To systematically review evidence evaluating cannabis-related knowledge and perception of risk in children and adolescents. We systematically searched Medline, PsycINFO, and EMBASE using Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology. 133 studies from around the world (including ages 10-18 yrs) met inclusion criteria, with 70% meeting grade 2C quality. Increased knowledge and perception of risk of cannabis frequently correlated with lower levels of current use and intent to use. Studies examining correlations over time generally demonstrated increased adolescent cannabis use and decreased perception of risk. Included prevention-based interventions often enhanced knowledge and/or perception of risk in adolescents exposed to the intervention. Studies exploring outcomes relating to legislative changes for recreational marijuana use demonstrated considerable heterogeneity regarding knowledge and perception of risk whereas studies that focused on medicinal marijuana legislative changes overwhelmingly demonstrated a decrease in perception of risk post legalization. Increased knowledge and perception of risk of cannabis in adolescents often correlate with lower levels of current use and intention to use in the future. Further study and implementation of public health and clinically-oriented strategies that seek to increase knowledge among youth about the potential health harms of cannabis use should continue and be prioritized.

Youth Exposure to Recreational Cannabis Legalization: Moderation of Effects by Sex and Parental Cannabis Use during Adolescence

OBJECTIVE

Few studies of recreational cannabis legalization (RCL) have assessed adolescents both before and after RCL or considered moderators of RCL effects. The present study tested whether RCL was more strongly associated with cannabis use for girls and among youth whose parents had a history of cannabis use during adolescence.

METHOD

Data were pooled from 940 adolescents from three intergenerational studies that began in Washington (where RCL was enacted in 2012), Oregon (RCL year = 2015), and New York (RCL year = 2021). Youth were assessed repeatedly from ages 13 to 18 years (k = 3,650 person-years) from 1999 to 2020 (prior to RCL in New York). Parent cannabis use at or before age 18 years (yes/no) was assessed prospectively during the parent's adolescence. Multilevel models focused on the between-subjects effects of years of youth exposure to RCL on adolescents' mean cannabis use likelihood, and interactions with child sex and parent use history.

RESULTS

Child exposure to RCL was associated with a higher likelihood of cannabis use if their parents had a history of adolescent use, (Estimate [SE] = 0.67 [0.25], p = 0.008), versus no such history (Estimate [SE] = -0.05 [0.28], p = 0.855). RCL effects were not moderated by child sex.

CONCLUSIONS

The effects of RCL on adolescents' cannabis use may depend on their parents' history of using the drug. Identifying other moderators of RCL effects, and understanding the mechanisms of these risks and the ways that parents and communities can offset them, are prevention priorities.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

A cross-cultural fMRI investigation of cannabis approach bias in individuals with cannabis use disorder

Introduction

As cannabis policies and attitudes become more permissive, it is crucial to examine how the legal and social environment influence neurocognitive mechanisms underlying cannabis use disorder (CUD). The current study aimed to assess whether cannabis approach bias, one of the mechanisms proposed to underlie CUD, differed between environments with distinct recreational cannabis policies (Amsterdam, The Netherlands (NL) and Dallas, Texas, United States of America (TX)) and whether individual differences in cannabis attitudes affect those differences.

Methods

Individuals with CUD (NL-CUD: 64; TX-CUD: 48) and closely matched non-using controls (NL-CON: 50; TX-CON: 36) completed a cannabis approach avoidance task (CAAT) in a 3T MRI. The cannabis culture questionnaire was used to measure cannabis attitudes from three perspectives: personal, family/friends, and state/country attitudes.

Results

Individuals with CUD demonstrated a significant behavioral cannabis-specific approach bias. Individuals with CUD exhibited higher cannabis approach bias-related activity in clusters including the paracingulate gyrus, anterior cingulate cortex, and frontal medial cortex compared to controls, which was no longer significant after controlling for gender. Site-related differences emerged in the association between cannabis use quantity and cannabis approach bias activity in the putamen, amygdala, hippocampus, and insula, with a positive association in the TX-CUD group and a negative association in the NL-CUD group. This was not explained by site differences in cannabis attitudes.

Conclusions

Pinpointing the underlying mechanisms of site-related differences-including, but not limited to, differences in method of administration, cannabis potency, or patterns of substance co-use-is a key challenge for future research.

Pre-Post Cannabis Legalization for Adult Use: A Trend Study of Two Cohorts of Young Adult Cannabis Users in Los Angeles

Cannabis was legalized for adult use in California in 2016 for individuals 21 and older. Among 18-20-years-olds, who can possess cannabis legally as medical cannabis patients (MCP) but not as non-patient cannabis users (NPU), the impact of adult use legalization (AUL) on cannabis and other substance use is unknown. Two cohorts of 18-20-year-old cannabis users (MCP and NPU) were surveyed, one in 2014-15 (n = 172 "pre-AUL") and another in 2019-20 (n = 139 "post-AUL"), using similar data collection methods in Los Angeles, California. Logistic and negative binomial regressions estimated cohort and MCP differences for cannabis and other drug use outcomes based on past 90-day use. In both pre- and post-AUL cohorts, MCP were more likely to self-report medical cannabis use (p < .001) while the post-AUL cohort reported greater use of edibles (p < .01), but fewer mean days of alcohol (p < .05) and cigarette (p < .01) use in multivariate models. Notably, frequency of cannabis use (days or hits per day) did not significantly differ between the pre- and post-AUL cohorts, except for greater use of edibles, despite potentially greater access to cannabis.

Adolescent simultaneous use of alcohol and marijuana by trends in cigarette and nicotine vaping from 2000 to 2020

BACKGROUND

Simultaneous alcohol and marijuana (SAM) use is associated with adverse consequences for youth. While SAM use is overall declining among youth, prior studies indicate increasing marijuana use among US adolescents who ever used cigarettes, suggesting possible moderation of the alcohol-marijuana relationship by cigarette use.

METHODS

We included 43,845 12-th grade students participating in Monitoring the Future data (2000-2020). A 5-level alcohol/marijuana measure was used, including past-year SAM, alcohol-only, marijuana-only, non-simultaneous alcohol and marijuana, or no use. Multinomial logistic regressions estimated associations between time periods (categorized based on sample size: 2000-2005, 2006-2009, 2010-2014, 2015-2020) and the 5-level alcohol/marijuana measure. Models adjusted for sex, race, parental education and survey mode and included interactions of time periods and lifetime cigarette or vaped nicotine use.

RESULTS

While overall SAM among 12th graders decreased from 23.65% to 18.31% between 2000 and 2020, SAM increased among students who never used cigarettes or vaped nicotine (from 5.42% to 7.03%). Among students who ever used cigarettes or vaped nicotine, SAM increased from 39.2% in 2000-2005-44.1% in 2010-2014 then declined to 37.8% in 2015-2020. Adjusted models controlling for demographics indicated that among students with no lifetime cigarette or vaped nicotine use, students in 2015-2020 had 1.40 (95% C.I. 1.15-1.71) times the odds of SAM, and 5.43 (95% C.I. 3.63-8.12) times the odds of marijuana-only (i.e., no alcohol use) compared to students who used neither in 2000-2005. Alcohol-only declined over time in both students who ever and never used cigarettes or nicotine vape products.

CONCLUSION

Paradoxically, while SAM declined in the overall adolescent US population, the prevalence of SAM increased among students who have never smoked cigarettes or vaped nicotine. This effect arises because of a substantial decline in the prevalence of cigarette smoking; smoking is a risk factor for SAM, and fewer students smoke. Increases in vaping are offsetting these changes, however. Preventing adolescent use of cigarettes and nicotine vaped products could have extended benefits for other substance use, including SAM.

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.

Risk Factors for Adolescent Cannabis Use in a State With Legal Recreational Cannabis: The Role of Parents, Siblings, and Friends

PURPOSE

Cannabis use during adolescence can have harmful consequences, including poor educational outcomes, neurocognitive defects, and an increased risk of addiction to other drugs, such as tobacco, alcohol, and opioids. Perceived family and social network cannabis use is a risk factor for use among adolescents. It is not currently known whether there is an association between perceived family/social network cannabis use and adolescent cannabis use in the context of legalization. The purpose of this study was to examine associations between adolescent perceptions of parent, sibling, and best friend medical and/or recreational cannabis use and adolescents' own use and whether the association changed pre-legalization and post-legalization in Massachusetts.

METHODS

We analyzed responses from surveys administered to students at 2 high schools in Massachusetts before legalization in 2016 (wave 1) and after legalization but before the start of regulated retail cannabis sales in 2018 (wave 2). We used χ2 tests and multiple logistic regression to examine associations between adolescent perception of parent, sibling, and best friend use and adolescent past 30-day cannabis use before and after legalization.

FINDINGS

In this sample, no statistically significant differences were found in the prevalence of past 30-day cannabis use before and after legalization among adolescents. There was an increase in the proportion of adolescents who reported any perceived parent cannabis use from before to after legalization (18% before legalization to 24% after legalization; P = 0.018). Perceived parent, sibling, and best friend medical and recreational cannabis use were all associated with an increased odds of adolescent use, with the highest increase in odds found for perceived best friend use (adjusted odds ratio, 17.2; 95% CI, 12.4-24.0).

IMPLICATIONS

Adolescent perceptions of their parents as cannabis users increased after legalization, even before state-regulated retails sales began. Parent, sibling, and best friend cannabis use is each independently associated with increased odds of adolescent's own use. These findings from 1 Massachusetts district should be explored in larger and more representative populations and motivate additional attention to interventions that consider family and friend influences when seeking to address adolescent cannabis use.

Cannabis vaping among high school seniors in adult-use, medical, and prohibited legal contexts

Background

Vaping cannabis among adolescents has been increasing. Monitoring the Future (MTF) indicated in 2019 that past-month cannabis vaping among 12th graders underwent the second-highest single-year jump ever tracked by MTF for any substance in its 45-year history. These increases in adolescents who vape cannabis do not parallel declining general adolescent cannabis use trends. Nevertheless, research on cannabis consumption via vaping, especially among adolescents, has been substantially limited.

Method

We examined associations between legal contexts (prohibited, medical, and adult use) and vaping cannabis in the past year among high school seniors. In addition, associations between vaping cannabis and factors such as availability and acceptability were examined using secondary data from MTF (2020), with a sub-sample size of 556 participants (overall sample size: n = 3,770), using multivariate logistic regression models.

Results

We found that high school seniors in medical states had higher odds of past-year vaping cannabis, but 12th graders in adult-use states were not significantly more likely to vape cannabis than those in prohibited states. Increased availability of vaping products and decreased risk perceptions in medical states may explain this relationship. Adolescents who perceived high risks associated with regular cannabis use had decreased odds of vaping cannabis. High school seniors reporting very easy access to cannabis cartridges had increased odds of vaping cannabis, regardless of legal context.

Conclusion

These results contribute knowledge about contextual factors related to adolescent cannabis vaping, a relatively new technique of cannabis consumption for which there is growing societal concern.

The great decline in adolescent risk behaviours: Unitary trend, separate trends, or cascade?

In many high-income countries, the proportion of adolescents who smoke, drink, or engage in other risk behaviours has declined markedly over the past 25 years. We illustrate this behavioural shift by collating and presenting previously published data (1990-2019) on smoking, alcohol use, cannabis use, early sexual initiation and juvenile crime in Australia, England, the Netherlands, New Zealand, and the USA, also providing European averages where comparable data are available. Then we explore empirical evidence for and against hypothesised causes of these declines. Specifically, we explore whether the declines across risk behaviours can be considered 1) a 'unitary trend' caused by common underlying drivers; 2) separate trends with behaviour-specific causes; or 3) the result of a 'cascade' effect, with declines in one risk behaviour causing declines in others. We find the unitary trend hypothesis has theoretical and empirical support, and there is international evidence that decreasing unstructured face-to-face time with friends is a common underlying driver. Additionally, evidence suggests that behaviour-specific factors have played a role in the decline of tobacco smoking (e.g. decreasing adolescent approval of smoking, increasing strength of tobacco control policies) and drinking (e.g. more restrictive parental rules and attitudes toward adolescent drinking, decreasing ease of access to alcohol). Finally, declining tobacco and alcohol use may have suppressed adolescent cannabis use (and perhaps other risk behaviours), but evidence for such a cascade is equivocal. We conclude that the causal factors behind the great decline in adolescent risk behaviours are multiple. While broad contextual changes appear to have reduced the opportunities for risk behaviours in general, behaviour-specific factors have also played an important role in smoking and drinking declines, and 'knock-on' effect from these behavioural domains to others are possible. Many hypothesised explanations remain to be tested empirically.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

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.

Same, opposite and both-sex attracted adolescents' mental health, safe-sex practices and substance use

This study examined mental health, substance use, and sexual health across sexual attraction groups. 428 adolescents recruited from school-based health centers completed self-report measures. 72% were only opposite-sex attracted, 19% both-sex attracted, 3% same-sex attracted, 4% not sure. Reported partners did not always align with reported attraction. Compared to opposite-sex attracted youth, 1) both-sex attracted youth had significantly higher rates of marijuana use (OR=1.75, p=.04), depressive symptoms (OR=2.62, p=.001) and inconsistent condom use (OR=1.71, p=.05); 2) the "not sure" group had higher anxiety symptoms (OR=4, p=.01). This study highlights the importance of considering sexual attraction in providing quality care to young people.

Cannabis Legalization and Adolescent Use of Electronic Vapor Products, Cannabis, and Cigarettes

OBJECTIVES

Cannabis legalization may have unintended consequences, such as effects on prevalence of adolescent use of other substances. We hypothesize that in states that have legalized recreational cannabis (RCL states), electronic vapor product use ("vaping"), cannabis, and cigarette use among adolescents is more prevalent than in states that have only legalized medical cannabis (MCL states) and states that have neither legalized recreational nor medical cannabis (NL states).

METHODS

Data are from the Center for Disease Control's 2017 Youth Risk Behavior Surveillance Survey (n = 107,665), a nationally representative survey of US high school students. We categorized student responses by cannabis legalization status of the state in which they lived at time of survey, then tested associations between cannabis legalization status and adolescent vaping, cannabis, and cigarette use, using logistic regressions.

RESULTS

Students in RCL states were significantly more likely to report current vaping behaviors compared to NL students [odds ratios (OR's) 2.07-2.21]. Students in cannabis-legal states were significantly more likely to report ever or currently using cannabis compared to NL students (OR's 1.27-1.40). MCL students were significantly less likely to report current cigarette smoking (OR = 0.86) compared to NL students.

CONCLUSIONS

Adolescents in cannabis-legal states were more likely to report vaping and cannabis use compared to adolescents in NL states. Public health officials, policymakers, and clinicians should consider the associations between cannabis legalization and adolescent vaping, cigarette, and cannabis use patterns.

Joint perceptions of the risk and availability of Cannabis in the United States, 2002-2018

BACKGROUND

Prior work suggests that perceived risk and perceived availability of cannabis independently affect cannabis use. However, perceived risk likely modifies the effect of perceived availability, and vice versa. This study explored trends in joint perceived risk and availability of cannabis from 2002 to 2018 and the relationship between combined perceptions and cannabis use, frequent use, and cannabis use disorder (CUD).

METHODS

National Surveys on Drug Use and Health data (n = 949,285, ages 12+) were used to create combined categories of perceived risk of weekly cannabis use and perceived cannabis availability. Descriptive analyses compared joint perceived risk/availability trends (pre/post-2015 due to survey redesign) overall and stratified by age, gender, past-year cannabis use, frequent use, and CUD. Regression analysis estimated associations between perceived risk/availability and cannabis outcomes.

RESULTS

From 2002 to 2018, the prevalence of perceiving cannabis as low-risk doubled while perceiving cannabis as available remained unchanged. The proportion of individuals perceiving cannabis as Low-risk/Available increased by 86% from 2002 to 2014 (16.8%-31.2%) and 19% from 2015 to 2018 (30.1%-35.8%) while High-risk/Available and High-risk/Unavailable proportions declined. Differing patterns were observed by age and gender. Compared with individuals perceiving cannabis as High-risk/Unavailable, people in all other perception categories had greater risk of all cannabis outcomes. Results were consistent with additive interaction between perceived risk and availability in their effects on cannabis use.

CONCLUSIONS

Trends and associations with cannabis outcomes differ when considering perceived risk and availability independently versus jointly. Longitudinal studies and cannabis policy evaluations would advance understanding of links between cannabis perceptions and use.

Density of medical and recreational cannabis outlets: racial/ethnic differences in the associations with young adult intentions to use cannabis, e-cigarettes, and cannabis mixed with tobacco/nicotine

BACKGROUND

Differences in access to medical versus recreational cannabis outlets and their associations with intentions to use cannabis have not yet been examined among young adults. This study compares the associations between densities of medical versus recreational cannabis outlets and young adults' intentions to use cannabis, electronic cigarettes, and cannabis mixed with tobacco/nicotine products. Racial/ethnic differences in these associations were examined.

METHODS

Young adults ages 18-23 (mean age = 20.9) in Los Angeles County were surveyed online in 2018 after the legalization of recreational cannabis (n = 604). Multiple linear regressions were estimated for the entire sample and stratified by race/ethnicity. Outcomes were intentions to use cannabis, electronic cigarettes, and cannabis mixed with tobacco/nicotine in the next 6 months. Density was measured as the number of medical cannabis dispensaries (MCDs), recreational cannabis retailers (RCRs), and outlets of any type within 5 miles of respondents' homes.

RESULTS

Living near more outlets of any type was not significantly associated with intentions to use in the full sample, adjusting for individual- and neighborhood-level characteristics. However, race/ethnicity-stratified models indicated that living near more outlets of any type and more RCRs were significantly associated with stronger co-use intentions among white young adults. Higher MCD density was marginally associated with stronger co-use intentions among Asian young adults. However, higher MCD density was significantly associated with lower intentions to use e-cigarettes among Hispanic young adults.

CONCLUSIONS

The results suggest racial/ethnic differences in the impact of living near cannabis outlets on intentions to use. Prevention efforts targeting young adults who live near more cannabis outlets may be especially beneficial for white and Asian 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.

Smoke in the air - Associations between experimentation with cannabis and the use of tobacco and nicotine products among 15-16-year-old school students

BACKGROUND

Cannabis is the most popular illicit drug among adolescents in developed countries, including Finland. The aim of this study was to estimate 1) how cannabis experimentation among Finnish adolescents changed between 2003 and 2019, and 2) whether the associations between cannabis experiments and factors related to it, especially the use of tobacco and nicotine products, changed during the same time period.

METHODS

The analyses are based on the European School Survey Project on Alcohol and Other Drugs data, collected from Finnish adolescents aged 15 to 16 in 2003, 2007, 2011, 2015, and 2019 (N = 20,630).

RESULTS

Experimentation with cannabis among Finnish adolescents has increased since the beginning of our follow-up. At the same time, alcohol use and smoking have decreased markedly, and attitudes toward cannabis use have become more relaxed. The association between smoking and cannabis experimentation has become weaker over time. However, the use of tobacco and nicotine products, especially polytobacco, is still a strong risk factor for experimentation with cannabis. The higher the number of tobacco or nicotine products used, the higher the probability for cannabis experimentation.

CONCLUSIONS

Experimentation with cannabis has previously been concentrated predominantly on adolescents who smoke, but recently non-smokers are increasingly trying cannabis. It is possible that alternative ways of using cannabis may have increased its use. Despite the strict cannabis policy in Finland, its use has increased, which may be an indication that youth cultures and images of different substances play a significant role in adolescents experimenting with cannabis.

Evaluating the effect of retail marijuana legalization on parent marijuana use frequency and norms in U.S. States with retail marijuana legalization

OBJECTIVES

To examine post-retail marijuana legalization (RML) change in marijuana use frequency and pro-marijuana norms among parents.

METHODS

The Intergenerational Study, a longitudinal panel of parents (N = 668) and children, followed participants from 2002 to 2018, when parents were 27 and 43 years old, respectively. Three quarters of participants (74%) lived in an RML state and 142 (21%) had used marijuana in the 8 years prior to RML. Piecewise growth modelling compared pre- and post-RML slopes of use frequency and pro-marijuana norms.

RESULTS

Frequency of use and pro-marijuana norms increased following legalization in both RML and non-RML states, though norms rose significantly faster in RML states. Growth in use was primarily driven by new users of marijuana. There were no differences in frequency of marijuana use or pro-marijuana norms by race/ethnicity, gender, or education.

CONCLUSIONS

An increase in marijuana use frequency associated with RML among parents poses risk to both parents' well-being and the health of their children. A faster pace of increase in pro-marijuana norms in RML states may signal continued increases in use in the future.

Marijuana Legalization and Youth Marijuana, Alcohol, and Cigarette Use and Norms

INTRODUCTION

Rates of adolescent substance use have decreased in recent years. Knowing whether nonmedical marijuana legalization for adults is linked to increases or slows desirable decreases in marijuana and other drug use or pro-marijuana attitudes among teens is of critical interest to inform policy and promote public health. This study tests whether nonmedical marijuana legalization predicts a higher likelihood of teen marijuana, alcohol, or cigarette use or lower perceived harm from marijuana use in a longitudinal sample of youth aged 10-20 years.

METHODS

Data were drawn from the Seattle Social Development Project-The Intergenerational Project, an accelerated longitudinal study of youth followed both before (2002-2011) and after nonmedical marijuana legalization (2015-2018). Analyses included 281 youth surveyed up to 10 times and living in a state with nonmedical marijuana legalization between 2015 and 2018 (51% female; 33% white, 17% African American, 10% Asian/Pacific Islander, and 40% mixed race or other).

RESULTS

Multilevel modeling in 2019 showed that nonmedical marijuana legalization predicted a higher likelihood of self-reported past-year marijuana (AOR=6.85, p=0.001) and alcohol use (AOR 3.38, p=0.034) among youth when controlling birth cohort, sex, race, and parent education. Nonmedical marijuana legalization was not significantly related to past-year cigarette use (AOR=2.43, p=0.279) or low perceived harm from marijuana use (AOR=1.50, p=0.236) across youth aged 10-20 years.

CONCLUSIONS

It is important to consider recent broad declines in youth substance use when evaluating the impact of nonmedical marijuana legalization. States that legalize nonmedical marijuana for adults should increase resources for the prevention of underage marijuana and alcohol use.

Marijuana use trends among college students in states with and without legalization of recreational use: initial and longer-term changes from 2008 to 2018

BACKGROUND AND AIMS

Young adult college students in the United States are likely to be affected by marijuana liberalization trends. However, changes in students' marijuana use following recreational marijuana legalization (RML) have not been examined in more than one RML state at a time, or beyond 1-2 years post-legalization.

DESIGN

Cross-sectional National College Health Assessment survey administered twice yearly from 2008 to 2018.

SETTING

A total of 587 4-year colleges and universities in 48 US states.

PARTICIPANTS

Undergraduates aged 18-26 years attending college in US states that did (n = 234 669 in seven states) or did not (n = 599 605 in 41 states) enact RML between 2008 and 2018.

MEASUREMENTS

Self-reported marijuana use (past 30 days) and individual and contextual covariates, institution-provided institutional and community covariates and publicly available dates when states enacted RML.

FINDINGS

Adjusting for covariates, state differences and state-specific linear time trends (accounting for pre-RML trends), prevalence of 30-day marijuana use increased more among students exposed to RML [odds ratio (OR) = 1.23, 95% confidence interval (CI) = 1.19-1.28, P < 0.001] than among non-RML state students throughout the same time-period; the results were similar for frequent use (≥ 20 days) (OR = 1.18, 95% CI = 1.10-1.27, P < 0.001). Interaction models supported stronger RML effects among students who were female, residing off-campus and aged 21 years and older; sexual orientation did not moderate RML effects. In the earliest states to enact RML (2012) there were increases in use prevalence in the second through the sixth year post-RML compared to pre-RML. In the second legalization group (2015) there were increases in the first and second year post-RML, and greater increases in the third year. In the later states (2016-17), increases were observed in both years after RML.

CONCLUSIONS

In US states that enacted recreational marijuana legislation from 2012 to 2017 there was evidence for a general trend towards greater increases in marijuana use by college students and differential impact by gender, legal using age and campus residence.

Modes of Marijuana Consumption Among Colorado High School Students Before and After the Initiation of Retail Marijuana Sales for Adults

OBJECTIVE

This study aimed to estimate the prevalence of different modes of marijuana consumption (e.g., smoking, ingesting) overall and by sociodemographic factors, marijuana-related perceptions, and other substance use among adolescents, as well as to characterize differences in the usual mode of consumption before and after the initiation of retail marijuana sales in 2014.

METHOD

Data are from the 2013 and 2015 administrations of the Healthy Kids Colorado Survey, a cross-sectional, school-based survey. We included 9th-12th grade students who reported past-30-day marijuana use in 2013 (n = 2,792; 44.8% female) or 2015 (n = 1,664; 48.9% female). We estimated the prevalence of any past-month use of each mode in 2015 and usual mode of consumption the past month in both years. We tested differences by year, sociodemographics, marijuana-related perceptions, and other substance use using Rao-Scott chi-square tests and multivariable logistic regression.

RESULTS

The prevalence of past-month marijuana use was 20.7% in both years. In 2015, 39.8% of students reported using multiple modes in the past month. Use of any mode other than smoking and use of multiple modes differed by sociodemographics, marijuana-related perceptions, and other substance use. Smoking remained the most common usual mode in 2015. The prevalence of usually ingesting significantly decreased from 4.7% to 2.1% between years, whereas "other mode(s)" significantly increased from 4.0% to 6.0%.

CONCLUSIONS

The use of multiple modes of marijuana consumption was prevalent among adolescents in Colorado. The usual mode of consumption changed in years before and after the implementation of retail marijuana sales, suggesting the need for continued surveillance.

Race/Ethnicity Differences in Trends of Marijuana, Cigarette, and Alcohol Use Among 8th, 10th, and 12th Graders in Washington State, 2004-2016

Accurate estimates of substance use in the teenage years by race/ethnicity may help identify when to intervene to prevent long-term substance use disparities. We examined trends in past 30-day use of marijuana, cigarette, and alcohol among 8th, 10th, and 12th graders in Washington State, which passed a recreational marijuana law in 2012 and initiated retail marijuana sales in 2014. Data are from the 2004-2016 Washington Healthy Youth Surveys (n = 161,992). We used time series regression models to assess linear and quadratic trends in substance use for the full sample and stratified on race/ethnicity and grade level and examined relative differences in prevalence of use by race/ethnicity. In Washington, across all racial/ethnic groups, marijuana use peaked in 2012. Although there was not a significant overall change in marijuana use for the full sample across the study period, there was a statistically significant increase in use among 12th graders and a statistically significant decrease among 8th graders. Relative to Whites, Asians had a lower prevalence of marijuana use, whereas all other race/ethnicity groups had a higher prevalence of use. Prevalence of marijuana use is particularly high among American Indian/Alaska Native and Black youth and has increased most rapidly among 12th grade Hispanic/Latinx youth. There were large and statistically significant decreases in alcohol and cigarette use across the study period for the full sample, as well as for each race/ethnicity group. These findings highlight the need for continued monitoring of trends in use among these groups and potentially warrant consideration of selective interventions that specifically focus on students of color and that include developmentally-appropriate strategies relevant to each grade.

The Interplay Between Marijuana-Specific Risk Factors and Marijuana Use Over the Course of Adolescence

Permissive attitudes and norms about marijuana use and perceptions of low harm from use are considered risk factors for adolescent marijuana use. However, the relationship between risk and use may be reciprocal and vary across development and socializing domains. We examined the bidirectional relationships between marijuana-specific risk factors in individual, parent, peer, and community domains and adolescent marijuana use. Longitudinal data came from a sample of 2002 adolescents in 12 communities. Controlling for sociodemographic covariates and communities in which the individuals resided, autoregressive cross-lagged models examined predictive associations between the risk factors and marijuana use. After accounting for concurrent relationships between risk and use and stability in behavior over time, early adolescence and the transition to high school were particularly salient developmental time points. Specifically, higher risk in all four domains in grades 7 and 9 predicted greater use 1 year later. Moreover, youth's perception of lax community enforcement of laws regarding adolescent use at all time points predicted increases in marijuana use at the subsequent assessment, and perceived low harm from use was a risk factor that prospectively predicted more marijuana use at most of the time points. Finally, greater frequency of marijuana use predicted higher levels of risk factors at the next time point in most socializing domains throughout adolescence. Prevention programs should take into account developmental transitions, especially in early adolescence and during the transition to high school. They also should focus on the reciprocal relationships between use and risk across multiple socializing domains.

Associations between young adult marijuana outcomes and availability of medical marijuana dispensaries and storefront signage

AIMS

We investigated associations between the density of medical marijuana dispensaries (MMDs) around young adults' homes and marijuana use outcomes.

DESIGN

Secondary data analysis.

SETTING

Los Angeles County, CA, USA.

PARTICIPANTS

A total of 1887 participants aged 18-22 years, surveyed online in 2016-17.

MEASUREMENTS

Outcomes were past-month marijuana use (number of days used, number of times each day), positive expectancies and perceived peer use. Density was measured as the total number of MMDs and number of MMDs with storefront signage indicative of marijuana sales, within 4 miles of respondents' homes.

FINDINGS

Eighty-four per cent of respondents had 10 or more MMDs within 4 miles of their homes. Multiple linear regression analyses that adjusted for individual-level socio-demographic characteristics and neighborhood socio-economic status indicated that living near a higher number of MMDs was associated with greater number of days used in the past month [β = 0.025; 95% confidence interval (CI) = 0.001, 0.049; P = 0.04] and higher positive marijuana expectancies (β = 0.003; 95% CI = 0.001, 0.007; P = 0.04). Living near more MMDs with storefront signage had a four- to six-fold larger effect on number of times used per day and positive expectancies, respectively, compared with associations with the total MMD count. Adjusting for medical marijuana card ownership attenuated the association with number of days used in the past month and positive expectancies, and an unexpected association emerged between higher MMD density and fewer number of times used each day (β = -0.005; 95% CI = -0.009, -0.001; P = 0.03).

CONCLUSIONS

For young adults in Los Angeles County, living near more medical marijuana dispensaries (MMDs) is positively associated with more frequent use of marijuana within the past month and greater expectations of marijuana's positive benefits. MMDs with signage show stronger associations with number of times used each day and positive expectancies.

The impact of recreational marijuana legalization on rates of use and behavior: A 10-year comparison of two cohorts from high school to young adulthood

Although many states' policies and laws concerning marijuana use have recently become more permissive, little is known about the impact of recreational marijuana legalization (RML) on rates of use, risk factors associated with use, and patterns of use over time. We compared samples from 2 longitudinal studies focused on understanding risk and protective factors related to substance use from adolescence to young adulthood (N = 1,468). The samples were collected 10 years apart from the same neighborhoods in an urban area, and the same measures, research design, and data collection procedures were used in each study. As such, the samples are matched on many demographic variables and provide a unique opportunity to compare rates of use and other associated risk factors before and after RML in Oregon. Our results suggest increased marijuana use in a 30-day time frame among Sample 2 during the young adult years, the time at which RML went into effect in Oregon. In Sample 2, young adults had 2.12 times the odds in Sample 1 of using marijuana at age 24, and they were more likely than those in Sample 1 to report use over multiple time points in young adulthood. Overall, our results suggest that young adults after RML are more likely to use marijuana than young adults were before RML 10 years earlier. Implications for prevention and education are discussed in light of rising rates of daily and 30-day use patterns among this population. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Investigating how perceived risk and availability of marijuana relate to marijuana use among adolescents in Argentina, Chile, and Uruguay over time

AIMS

Amid changing marijuana policies in the Southern Cone, we examined relationships between marijuana-related risk factors and marijuana use among adolescents in Argentina, Chile, and Uruguay from 2001 to 2016.

METHODS

Using cross-sectional surveys from 8^th, 10^th, and 12^th graders and weighted time-varying effect models, we estimated associations between perceived risk (no/low risk versus moderate/great risk) and perceived availability (easy/very easy versus difficult/very difficult/not able to obtain) of marijuana, and any past-month marijuana use.

RESULTS

In all countries, marijuana use increased over time and adolescents who perceived no/low risk and easy availability had higher odds of use. In Argentina, the bivariate risk/use association weakened from 2001 (OR = 15.24, 95%CI = 9.63, 24.12) to 2004 [OR = 3.86 (2.72, 5.48)] and strengthened until 2011 [OR = 8.22 (7.56, 10.30)]; the availability/use association strengthened from 2005 [OR = 5.32 (4.05, 6.98)] to 2009 [OR = 20.77 (15.57, 27.70)] and weakened until 2014 [OR = 11.00 (9.11, 13.27)]. In Chile, the risk/use association weakened from 2001 [OR = 7.22 (6.57, 7.95)] to 2015 [OR = 5.58 (4.82, 6.48)]; the availability/use association weakened from 2001 [OR = 5.92 (4.96, 7.06)] to 2015 [OR = 4.10 (3.15, 5.34)]. In Uruguay, the risk/use association weakened from 2003 [OR = 34.22 (22.76, 51.46)] to 2016 [OR = 6.23 (4.96, 7.83)]; the availability/use association weakened from 2005 [OR = 29.13 (13.39, 63.39) to 2007 [OR = 9.42 (3.85, 23.07)], and strengthened until 2016 [OR = 22.68 (12.03, 42.76)].

CONCLUSIONS

Overall, the association between risk and use weakened in all countries, suggesting risk perceptions became a weaker determinant of marijuana use. Perceived availability remained strongly associated with use and may become an increasingly important driver of use (particularly in Uruguay and Argentina).

Does liberalisation of cannabis policy influence levels of use in adolescents and young adults? A systematic review and meta-analysis

OBJECTIVES

To examine the effect of cannabis policy liberalisation (decriminalisation and legalisation) levels of use in adolescents and young adults.

DESIGN

Systematic review and meta-analysis.

INCLUSION CRITERIA

Included studies were conducted among individuals younger than 25 years and quantitatively assessing consequences of cannabis policy change. We excluded articles: (A) exclusively based on participants older than 25 years; (B) only reporting changes in perceptions of cannabis use; (C) not including at least two measures of cannabis use; (D) not including quantitative data; and (E) reviews, letters, opinions and policy papers. PubMed, PsycINFO, Embase and Web of Science were searched through 1 March 2018.

DATA EXTRACTION AND SYNTHESIS

Two independent readers reviewed the eligibility of titles and abstracts and read eligible articles, and four authors assessed the risk of bias (Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies). Extracted data were meta-analysed. The protocol was registered with PROSPERO.

RESULTS

3438 records were identified via search terms and four via citation lists; 2312 were retained after removal of duplicates, 99 were assessed for eligibility and 41 were included in our systematic review. 13 articles examined cannabis decriminalisation, 20 examined legalisation for medical purposes and 8 examined legalisation for recreational purposes. Findings regarding the consequences of cannabis decriminalisation or legalisation for medical purposes were too heterogeneous to be meta-analysed. Our systematic review and meta-analysis suggest a small increase in cannabis use among adolescents and young adults following legalisation of cannabis for recreational purposes (standardised mean difference of 0.03, 95% CI -0.01 to -0.07). Nevertheless, studies characterised by a very low/low risk of bias showed no evidence of changes in cannabis use following policy modifications.

CONCLUSIONS

Cannabis policy liberalisation does not appear to result in significant changes in youths' use, with the possible exception of legalisation for recreational purposes that requires monitoring.

TRIAL REGISTRATION NUMBER

CRD42018083950.

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.

Cannabis Prevalence and National Drug Policy in 27 Countries: An Analysis of Adolescent Substance Use

Prior research that assesses the relationship between cannabis policy and prevalence rates has yielded mixed results, perhaps due to the varying rigor of these investigations. Addressing some of these issues in rigor and informed by a rational choice theory (RCT), we hypothesize that those policies on the more punitive end of McDonald and colleagues' classification will be most effective. Examining legislation in 27 countries utilizing the Second International Self-Report Delinquency Study (ISRD-2) through hierarchical linear modeling (HLM) models with both individual- and country-level controls, we find little support for these hypotheses. Instead, results from our analysis largely indicate that the variation in country prevalence rates from 2005 to 2007 was not significantly related to cannabis control policy. We comment on possible policy implications for these preliminary results.

Sensation seeking to marijuana use: Exploring the mediating roles of risk appraisal and social norms

While studies have shown a robust association between sensation seeking (SS) and adolescent marijuana use, comparatively little is known about the mechanisms that potentially account for this association. The current study tests a theoretical model linking SS to marijuana use through risk appraisal and normative influences (i.e., perceived behavior and attitudes of others). Utilizing a nationally representative, cross-sectional sample of high school seniors (N = 2117), the current study finds risk appraisal and normative influences mediate the relationship between SS and marijuana use. Furthermore, perceptions of risk appear to be strongly influenced by proximal peer norms. These results indicate risk appraisal and normative processes may be key explanatory mechanisms in the association between SS and adolescent marijuana use. Theoretical and policy implications for this model are discussed.

Adolescent Marijuana Use, Marijuana-Related Perceptions, and Use of Other Substances Before and After Initiation of Retail Marijuana Sales in Colorado (2013-2015)

Due to the recentness of changes to marijuana policies in a number of states, the effect on adolescent use and perceptions is not yet well understood. This study examines change in adolescent marijuana use and related perceptions in Colorado, before and after the implementation of legal commercial sale of recreational marijuana for adults starting on January 1, 2014. The data are from a repeated cross-sectional survey of a representative sample of Colorado high school students, with separately drawn samples surveyed in fall 2013 (prior to implementation) and fall 2015 (18 months after implementation). We examined change in the prevalence of adolescent marijuana use, measured by lifetime use, past 30-day use, frequent use, and use on school property. To consider the possibility of heterogeneity in the change in marijuana use, we examined change in past 30-day marijuana use by demographic characteristics (sex, grade, race/ethnicity), school characteristics (poverty, percent minority), urbanicity of the school district, and whether the city or county permitted retail marijuana stores. There was an absence of significant effects for change in lifetime or past 30-day marijuana use. Among those reporting past 30-day use, frequent use and use on school property declined. There was a significant decline in the perceived harm associated with marijuana use, but we did not find a significant effect for perceived wrongfulness, perceived ease of access, or perceived parental disapproval. We did not find significant variability in past 30-day use by demographic characteristics or by school and community factors from 2013 to 2015. We did not find a significant effect associated with the introduction of legal sales of recreational marijuana to adults in Colorado on adolescent (illegal) use, but ongoing monitoring is warranted, including consideration of heterogeneity in the effects of marijuana policies.

PERCEPTION OF HARM AND BENEFITS OF MARIJUANA AND ITS RELATIONSHIP WITH THE INTENTION OF USE AND CONSUMPTION IN COLOMBIAN ADOLESCENTS

ABSTRACT Objective: analyze the relationship between the perception of harm and benefits associated with the use of marijuana and its relation to real consumption, as well as the intention to use it in a context of regulatory changes, in young students, between 15 and 17 years old, of a public school in Bogota Colombia. Method: a quantitative, cross-sectional survey was carried out. 268 students in grade 9th to 11th from a public school in the city of Bogotá, Colombia participated of the study. Results: results reveled that there is an association between the perception of benefits and the consumption of marijuana. In addition, how a low perception of risk is associated with an intention to use in a context of legalization. Conclusion: this is one of the first studies in Colombia which explores the intention to use (at age 18) in a context of regulatory changes, as well as the attitude of young people towards the legalization of marijuana for medicinal and recreational use.

The Implications of Cannabis Policy Changes in Washington on Adolescent Perception of Risk, Norms, Attitudes, and Substance Use

There is increasing interest in the effect of legalization (particularly recreational legalization) of cannabis on prevalence of use and related problems. However, there is no consensus about the impact of policy change on cannabis use, particularly among adolescents. Legalization may increase adolescent use through mediating factors such as perceived risk and normative beliefs regarding the use of cannabis. Washington State enacted Initiative 502 on December 2012, which legalized and taxed recreational cannabis for adults aged ⩾21 years. This paper used data from a randomized, controlled intervention trial for cannabis-using adolescents that was recruiting participants in Seattle before and after the policy change to evaluate the following goals: assess differences in substance use, problems, and symptomatology pre- and post-policy change; evaluate several proposed risk factors that may be associated with such differences; and describe participants’ understanding of the law and how this understanding may relate to rates of use. Analyses revealed no significant differences pre- to post-policy in rate of substance use. However, there were significant post-policy increases in problems and use disorder symptoms. Despite these differences, there were no significant increases in norms, attitudes, or perceptions of risk. Participants were able to answer most questions regarding policy changes correctly, indicating a good understanding of the policy. Results provided no evidence that policy change influenced heavy-using adolescents’ rates of use nor the proposed risk factors associated with problematic use patterns.

Patterns of marijuana use and physical health indicators among Canadian youth

We examine how trajectories of marijuana use in Canadian youth (ages 15 to 28) are related to physical health indicators in adolescence and young adulthood. Youth were initially recruited in 2003 (N = 662; 48% male; ages 12 to 18) and followed for six waves. Five trajectories of marijuana use (Abstainers-29%, Occasional users-27%, Decreasers-14%, Increasers-20% and Chronic users-11%) were identified. Chronic users reported more physical symptoms, poorer physical self-concept, less physical activity, poorer eating practices, less sleep, and higher number of sexual partners during adolescence than other classes. Decreasers also reported poorer physical self-concept and poorer eating practices than abstainers. Other trajectory classes showed few significant health problems. Chronic users also reported more acute health problems (i.e. serious injuries, early sexual debut, higher number of sexual partners, greater likelihood of having a STI) in young adulthood than all other classes contributing to costs of healthcare. Youth who engage in early, frequent and continued use of marijuana from adolescence to young adulthood are at-risk of physical health problems in adolescence and young adulthood.

Planting the seed for marijuana use: Changes in exposure to medical marijuana advertising and subsequent adolescent marijuana use, cognitions, and consequences over seven years

BACKGROUND

Marijuana use during adolescence is associated with neurocognitive deficits and poorer functioning across several domains. It is likely that more states will pass both medical and recreational marijuana legalization laws in the coming elections; therefore, we must begin to look more closely at the longitudinal effects of medical marijuana (MM) advertising on marijuana use among adolescents so that we can better understand effects that this advertising may have on their subsequent marijuana use and related outcomes.

METHODS

We followed two cohorts of 7th and 8th graders (mean age 13) recruited from school districts in Southern California from 2010 until 2017 (mean age 19) to examine effects of MM advertising on adolescents' marijuana use, cognitions, and consequences over seven years. Latent growth models examined trajectories of self-reported exposure to medical marijuana ads in the past three months and trajectories of use, cognitions, and consequences.

RESULTS

Higher average exposure to MM advertising was associated with higher average use, intentions to use, positive expectancies, and negative consequences. Similarly, higher rates of change in MM advertising exposure were associated with higher rates of change in use, intentions, expectancies, and consequences over seven years.

CONCLUSIONS

Results suggest that exposure to MM advertising may not only play a significant role in shaping attitudes about marijuana, but may also contribute to increased marijuana use and related negative consequences throughout adolescence. This highlights the importance of considering regulations for marijuana advertising, similar to regulations in place for the promotion of tobacco and alcohol in the U.S.

Recent rapid decrease in adolescents' perception that marijuana is harmful, but no concurrent increase in use

BACKGROUND

National trends in adolescent's marijuana risk perceptions are traditionally used as a predictor of concurrent and future trends in adolescent marijuana use. We test the validity of this practice during a time of rapid marijuana policy change.

METHODS

Two repeated cross-sectional U.S. nationally-representative surveys of 8th, 10th, and 12th-graders: Monitoring the Future (MTF) (1991-2015; N = 1,181,692) and National Survey on Drug Use and Health (NSDUH) (2002-2014; N = 113,317). We examined trends in the year-to-year prevalence of perceiving no risk of harm in using marijuana regularly, and prevalence of regular marijuana use within the previous month. A piecewise linear regression model tested for a change in the relationship between trends. Similar analyses examined any past-month use and controlled for demographic characteristics.

RESULTS

Among MTF 12th-graders, the prevalence of regular marijuana use and risk perceptions changed similarly between 1991 and 2006 but diverged sharply afterward. The prevalence of regular marijuana use increased by ∼1 percentage point to 6.03% by 2015. In contrast, the proportion of 12th-graders that perceived marijuana as posing no risk increased over 11 percentage points to 21.39%. A similar divergence was found among NSDUH 12th-graders and other grades, for any past month marijuana use, and when controlling demographic characteristics.

CONCLUSIONS

An increase in adolescent marijuana use has not accompanied recent rapid decreases in marijuana risk perceptions. Policy makers may consider broader prevention strategies in addition to targeting marijuana risk perceptions. Further monitoring of predictors of marijuana use trends is needed as states legalize recreational marijuana use.

Trends in Perceived Access to Marijuana Among Adolescents in the United States: 2002-2015

OBJECTIVE

There is concern that changes in marijuana-related policy and public opinion may lead to increased access to marijuana among young people in the United States. However, little research has been conducted on changes in youth's perceptions of marijuana access, and studies have yet to systematically examine trends in perceived access across key sociodemographic and externalizing behavioral subgroups.

METHOD

Using population-based data collected between 2002 and 2015 as part of the National Survey on Drug Use and Health, we examined trends in perceived marijuana access among non-Hispanic White, African American, and Hispanic adolescents (ages 12-17, n = 221,412). Following the trend analysis method outlined by the Centers for Disease Control and Prevention, we conducted logistic regression analyses to test for secular trends.

RESULTS

Between 2002 and 2015, we observed a 27% overall reduction in the relative proportion of adolescents ages 12-17-and a 42% reduction among those ages 12-14-reporting that it would be "very easy" to obtain marijuana. This pattern was uniformly observed among youth in all sociodemographic subgroups (i.e., across age, gender, race/ethnicity, household income) and among youth reporting involvement/no involvement in most measures of substance use (alcohol, marijuana) and delinquency (handgun carrying, attacks). However, perceived very easy access remained stable among youth reporting tobacco use and criminal justice system involvement.

CONCLUSIONS

Despite the legalization of recreational and medical marijuana in some states, our findings suggest that, with the notable exception of adolescent tobacco users and juvenile offenders, perceptions that marijuana would be very easy to obtain are on the decline among American youth.

Marijuana use during pregnancy: A comparison of trends and correlates among married and unmarried pregnant women

BACKGROUND/PURPOSE

While recent evidence indicates increases in marijuana use among adult women in the United States (US), important questions remain with respect to marijuana use during pregnancy. This study examines trends and correlates of prenatal marijuana use and the effects of marijuana-specific risk/protective factors on marijuana use trends using a nationally representative sample.

METHOD

Data were derived from the National Survey on Drug Use and Health (2005-2014), a nationally representative survey that included 3640 married and 3987 unmarried pregnant women in the United States. The significance of marijuana use trends was tested using logistic regression analyses while adjusting for complex sampling design effects and controlling for sociodemographic and marijuana-specific factors.

RESULTS

From 2005-2014, marijuana use prevalence among unmarried pregnant women increased by 85% from 5.4% to 10.0% while the prevalence among married pregnant women remained stable (mostly under 1.5%). The increasing trend among unmarried pregnant women was associated with their lower disapproval and risk perceptions of marijuana use. In addition, past-year anxiety (AOR=3.30, 95% CI=1.87-5.82) and depression (AOR=3.85, 95% CI=2.33-6.36) diagnoses were linked with marijuana use among unmarried, but not married, pregnant women.

DISCUSSION

Increased attention should be paid to reducing prenatal marijuana use among unmarried women. Findings also suggest the need to attend to unmarried pregnant women's mental health problems as well as their physical health-risk behaviors.

Risk is still relevant: Time-varying associations between perceived risk and marijuana use among US 12th grade students from 1991 to 2016

BACKGROUND

Perceived risk of harm has long been a key preventive factor for adolescent marijuana use. However, in recent years, perceived risk has decreased markedly and marijuana use has increased only slightly, leading to new questions about their association. This study investigates the magnitude and stability of the US adolescent marijuana risk/use association from 1991 to 2016, overall and by gender and race/ethnicity.

METHODS

Self-reported data on past 12-month marijuana use, perceived risk of regular marijuana use, gender, and race/ethnicity were obtained from 275,768 US 12th grade students participating in the nationally representative Monitoring the Future study. Time-varying effect modeling (TVEM) was used to examine the marijuana risk/use association over time.

RESULTS

Both before and after controlling for gender and race/ethnicity, perceived risk was a strong protective factor against adolescent marijuana use. The magnitude of the great risk/use association strengthened for Hispanic students; remained generally stable over time for 12th graders overall, males, females, and White students; and weakened for Black students. The magnitude of the moderate risk/use association strengthened for 12th graders overall, males, females, White and Hispanic students, but did not continue to strengthen for Black students from 2005 onwards. In general, marijuana use prevalence decreased over time within all levels of perceived risk.

CONCLUSIONS

Perceived risk remains a strong protective factor for adolescent marijuana use, and the protective association for moderate risk (vs. no/slight risk) is actually increasing over time. Results suggest that accurate and credible information on the risks associated with marijuana use should remain a key component of prevention efforts.

Changes in undergraduates' marijuana, heavy alcohol and cigarette use following legalization of recreational marijuana use in Oregon

BACKGROUND AND AIMS

Recreational marijuana legalization (RML) went into effect in Oregon in July 2015. RML is expected to influence marijuana use by adolescents and young adults in particular, and by those with a propensity for substance use. We sought to quantify changes in rates of marijuana use among college students in Oregon from pre- to post-RML relative to college students in other states across the same time period.

DESIGN

Repeated cross-sectional survey data from the 2012-16 administrations of the Healthy Minds Study.

SETTING

Seven 4-year universities in the United States.

PARTICIPANTS

There were 10 924 undergraduate participants. One large public Oregon university participated in 2014 and 2016 (n = 588 and 1115, respectively); six universities in US states where recreational marijuana use was illegal participated both in 2016 and at least once between 2012 and 2015.

MEASUREMENTS

Self-reported marijuana use in the past 30 days (yes/no) was regressed on time (pre/post 2015), exposure to RML (i.e. Oregon students in 2016) and covariates using mixed-effects logistic regression. Moderation of RML effects by recent heavy alcohol use was examined.

FINDINGS

Rates of marijuana use increased from pre- to post-2015 at six of the seven universities, a trend that was significant overall. Increases in rates of marijuana use were significantly greater in Oregon than in comparison institutions, but only among students reporting recent heavy alcohol use.

CONCLUSIONS

Rates of Oregon college students' marijuana use increased (relative to that of students in other states) following recreational marijuana legislation in 2015, but only for those who reported recent heavy use of alcohol. Such alcohol misuse may be a proxy for vulnerabilities to substance use or lack of prohibitions (e.g. cultural) against it.