Declining Prevalence of Marijuana Use Disorders Among Adolescents in the United States, 2002 to 2013

Spatial and temporal pattern of cannabis use disorder in California 2010-2019

As cannabis use is being legalized in an increasing number of states, it is important to understand the changing dynamic of the risk in cannabis use disorder (CUD). Shape-based time-series clustering was used to identify ZIP Code Tabulation Areas (ZCTAs) with similar changing pattern in CUD over time. We conducted a cross-sectional logistic regression analysis to investigate the most recent ZCTA socio-demographic characteristics in relation to the changing CUD rates. The emergency discharge rates generally increased during 2010-2016. Increase during 2017-2019 was found in Sacramento and Santa Barbara County. Approximately 13% of ZCTAs showed an increasing trend of hospitalization discharge during 2017-2019. Males and non-Hispanic Black had larger increase than other groups during 2017-2019. The recent growing trend was found associated with greater racial diversity and rural ZCTAs. The findings from this study hold promise for local public health officials to adjust the cannabis intervention strategies in target districts and improve overall health outcomes.

Co-ingestion of prescription drugs and alcohol in US adults aged 50 years or older

OBJECTIVE

To examine prevalence of past-month prescription drug misuse (PDM) and alcohol co-ingestion and its correlates in adults age 50 or older.

METHODS

Data were from the 2015-2018 US National Survey on Drug Use and Health (n = 35,190). PDM-alcohol co-ingestion was defined as prescription opioid, tranquilizer/sedative, or stimulant misuse while "drinking alcohol or within a couple of hours of drinking." Co-ingestion prevalence was estimated, and logistic and negative binomial regressions examined the sociodemographic, physical health, mental health, substance use, and substance use disorder (SUD) correlates of co-ingestion.

RESULTS

Over 344,000 adults aged 50 years or older (0.3%) engaged in past-month PDM-alcohol co-ingestion, or 27.4% of those with past-month PDM. Past-month co-ingestion was linked to greater past-month alcohol use frequency and elevated adjusted odds ratios (aORs) for all examined substance use outcomes (e.g., non-PDM SUD aOR = 21.8; 49.7% prevalence rate). The aOR for suicidal ideation was 506% higher in those with co-ingestion than those without past-year PDM.

CONCLUSIONS

US adults aged 50 years or older with past-month PDM-alcohol co-ingestion are at high risk for SUD and concerning mental health symptoms. Screening for mental health and substance use treatment is warranted among aging adults with signs of PDM, especially involving co-ingestion.

U.S. Trends in Adolescent Substance Use and Conduct Problems and Their Relation to Trends in Unstructured In-Person Socializing With Peers

PURPOSE

This study examined whether national trends in unstructured in-person socializing with peers (i.e., socializing without goals or supervision) among adolescents could help explain recent declines in adolescent risk behaviors (e.g., substance use, fighting, theft).

METHODS

The sample contained of 44,842 U.S. 12th-grade students (aged 17-18 years) from the Monitoring the Future survey (years 1999-2017). Analyses examined (1) prevalence trends, (2) latent factor structure of risk behaviors and unstructured in-person socializing, and (3) whether trends in the unstructured in-person socializing factor accounted for the relationship between time (i.e., survey year) and the risk behavior factor.

RESULTS

Adolescent risk behaviors and unstructured in-person socializing declined by approximately 30% in the U.S., and both formed coherent latent factors. After adjusting for sociodemographics, declines in unstructured in-person socializing accounted for approximately 86% of declines in risk behaviors.

CONCLUSIONS

The prevalence of risk behaviors and unstructured in-person socializing behaviors declined among U.S. 12th graders from 1999 to 2017. It is unknown whether such effects are directly causal and/or influenced by unmeasured variables. However, the results provide evidence that national declines in unstructured in-person socializing are a likely component of the explanation for national declines in adolescent risk behaviors.

Substance Use and Mental Health in Homeschooled Adolescents in the United States

PURPOSE

U.S. homeschooling increased by 50% over 2007-2016. Homeschooled adolescents may have lower substance use rates, but previous research treated other adolescents as homogeneous despite within-group differences. We used the 2015-2018 National Survey on Drug Use and Health to compare adolescent substance use and psychopathology by homeschooled/educational status.

METHODS

Data were from 52,089 adolescents, classified by educational status (i.e., homeschooled; public/private school, low dropout risk; public/private school, at risk for dropout; and not in school) and compared on substance use and psychopathology variables.

RESULTS

Substance use rates were lowest in adolescents at low dropout risk, with significantly lower past-year prescription opioid misuse, tobacco use, nonmarijuana illicit drug use, and nicotine dependence rates than homeschooled adolescents. Psychopathology treatment prevalence was lowest in homeschooled adolescents. Those at risk for dropout had the highest rates of substance use.

CONCLUSIONS

Although homeschooled adolescents have relatively low substance use rates, they exceed those of low dropout risk adolescents.

Retrospective cross-sectional analysis of the changes in marijuana use in the USA, 2005-2018

OBJECTIVES

Understanding trends of marijuana use in the USA throughout a period of particularly high adoption of marijuana-legalisation, and understanding demographics most at risk of use, is important in evolving healthcare policy and intervention. This study analyses the demographic-specific changes in the prevalence of marijuana use in the USA between 2005 and 2018.

DESIGN, SETTING AND PARTICIPANTS

A 14-year retrospective cross-sectional analysis of the National Health and Nutrition Examination Survey database, a publicly available biennially collected national survey, weighted to represent the entire US population. A total of 35 212 adults between 18 and 69 years old participated in the seven-cycles of surveys analysed (2005-2018).

PRIMARY OUTCOME MEASURED

Lifetime use, first use before 18 years old, and past-year use of marijuana.

RESULTS

The majority of adults reported ever using marijuana. While the overall prevalence of lifetime marijuana use remained stable (p=0.53), past-year use increased significantly between 2005 and 2018 (p<0.001) with highest rate of past-year use among younger age groups (p<0.001), males (p<0.001) and those with income below poverty level (p<0.001). Past-year use was the most common among non-Hispanic blacks, and less common among Hispanic/Mexican populations (p<0.002). Trends in past-year use increased among all age categories, males/females, all ethnicities, those with high school education/above, and those at all income levels (p<0.01 for all).

CONCLUSIONS

While lifetime marijuana use remained stable, past-year use significantly increased between 2005 and 2018. While past-year use remained the most common in younger age groups, males, non-Hispanic blacks and those with lower income; increasing trends in past-year use were significant for all age, sex, race and income categories, and for those with high school education/above. With high adoption of marijuana-legalisation laws during this period, our results suggest an associated increase in past-year marijuana use.An accurate understanding of those most at risk can help to inform decisions of healthcare policy-makers and professionals, and facilitate a safe transition of changing marijuana legalisation and use in the USA.

Age, period and cohort effects in frequent cannabis use among US students: 1991-2018

BACKGROUND AND AIMS

As the legal status of cannabis changes across the United States and modes of administration expand, it is important to examine the potential impact on adolescent cannabis use. This study aimed to assess changes in prevalence of frequent cannabis use in adolescents in the United States and how far this varies by age and cohort.

DESIGN

Analysis of Monitoring the Future, a nationally representative annual survey of 8th-, 10th- and 12th-grade students in the United States conducted from 1991 to 2018.

SETTING

In-school surveys completed by US adolescents.

PARTICIPANTS

A total of 1 236 159 8th-, 10th- and 12th-graders; 51.5% female, 59.6% non-Hispanic white, 12.3% non-Hispanic black, 13.4% Hispanic and 14.7% other race/ethnicity.

MEASUREMENTS

Frequent cannabis use (FCU), defined as six or more occasions in the past 30 days, stratified by sex, race/ethnicity and parental education.

FINDINGS

FCU among US adolescents increased over the study period; the peak in 2010-18 was 11.4% among 18-year-old students. This increase was best explained by both period and cohort effects. Compared with respondents in 2005, adolescents surveyed in 2018 had period effects in FCU that were 1.6 times greater. Adolescents in younger birth cohorts (those born > 1988) had a lower increase in FCU than those born prior to 1988. Results were consistent across sex, parent education and race/ethnicity, with period effects indicating increasing FCU after 2005 and cohort effects indicating a lower magnitude of increase in more recent birth cohorts. Age and parental education disparities in FCU have increased over time, whereas race/ethnicity differences have converged over time; black students were 0.67 [95% confidence interval (CI) = 0.64-0.70] times as likely to use cannabis frequently as white students from 1991 to 2000, and 1.03 (95% CI = 0.98-1.09) times as likely from 2011 to 2018 (P-value for time interaction < 0.001).

CONCLUSIONS

The prevalence of frequent cannabis use (FCU) increased from 1991 to 2018 among older adolescents in the United States. Racial/ethnic differences in FCU converged, whereas parental education differences have diverged.

Age Differences in Daily and Nondaily Cannabis Use in the United States, 2002-2014

OBJECTIVE

Adult cannabis use has increased in the United States since 2002, particularly after 2007, contrasting with stable/declining trends among youth. We investigated whether specific age groups disproportionately contributed to changes in daily and nondaily cannabis use trends.

METHOD

Participants ages 12 and older (N = 722,653) from the 2002-2014 National Survey on Drug Use and Health reported past-year cannabis use frequency (i.e., daily = ≥300 days/year; nondaily = 1-299 days/year; none). Multinomial logistic regression was used to model change in past-year daily and nondaily cannabis use prevalence by age group (i.e., 12-17, 18-25, 26-34, 35-49, 50-64, ≥65), before and after 2007. Multinomial logistic regressions estimated change in relative odds of cannabis use frequency over time by age, adjusting for other sociodemographics.

RESULTS

Daily cannabis use prevalence decreased in ages 12-17 before 2007 and increased significantly across adult age categories only after 2007. Increases did not differ significantly across adult ages 18-64 and ranged between 1 and 2 percentage points. Nondaily cannabis use decreased among respondents ages 12-25 and 35-49 before 2007 and increased across adult age categories after 2007, particularly among adults 26-34 (i.e., 4.5 percentage points). Adjusted odds of daily versus nondaily cannabis use increased after 2007 for ages 12-64.

CONCLUSIONS

Increases in daily and nondaily cannabis use prevalence after 2007 were specific to adult age groups in the context of increasingly permissive cannabis legislation, attitudes, and lower risk perception. Although any cannabis use may be decreasing among teens, relative odds of more frequent use among users increased in ages 12-64 since 2007. Studies should assess not only any cannabis use, but also frequency of use, to target prevention efforts of adverse effects of cannabis that are especially likely among frequent users.

Changes over time in marijuana use, deviant behavior and preference for risky behavior among US adolescents from 2002 to 2014: testing the moderating effect of gender and age

BACKGROUND AND AIMS

Among adolescents, risk preference and deviant behaviors are associated with marijuana use, which exhibit substantial historical trends. We examined (1) trends, (2) effect modification by sex and age, (3) associations of marijuana use with deviant behaviors and risk preferences and (4) differences by sex, age and year.

DESIGN

Adjusted logistic and relative risk regression models, using data from the 2002-14 National Survey on Drug Use and Health, annual cross-sectional surveys of US households.

SETTING

United States.

PARTICIPANTS

A nationally representative sample of adolescents aged 12-17 years (n = 230 452).

MEASUREMENTS

We estimated associations between past-year marijuana use [self-reported using computer-assisted personal interviewing/audio computer-assisted self-interviewing (CAPI/ACASI)], deviant behavior (i.e. selling drugs; stealing; attacking someone) and risk preference (i.e. getting a kick; testing oneself).

FINDINGS

Marijuana use, deviant behaviors and risk preferences declined among adolescents from 2002 to 2014. There were no significant sex or age differences in the decline of marijuana use over time. There were sex [sold drugs: β = 0.90, 95% confidence interval (CI) = 0.75, 1.04] and age (attacked someone: β = 0.32, 95% CI = 0.22, 0.42) differences in the prevalence of deviant behaviors, and trends over time differed by sex and age for attacking someone.

CONCLUSIONS

While marijuana use, deviant behavior and risk preferences among US adolescents declined from 2002 to 2014, associations have remained stable, with marijuana use positively associated with deviant behaviors and risk preferences.

Time trends in US cannabis use and cannabis use disorders overall and by sociodemographic subgroups: a narrative review and new findings

Background: Due to significant comorbidity and impairment associated with cannabis use and cannabis use disorder, understanding time trends in cannabis use and cannabis use disorder is an important public health priority.Objectives: To identify trends in cannabis use and cannabis use disorder overall, and by sociodemographic subgroup.Methods: Narrative review of published findings on trends in cannabis use and cannabis use disorders in data from repeated cross-sectional US general population surveys. In addition, in National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; 2002-2002) and NESARC-III (2012-2013) data, logistic regression was used to examine whether trends differed between subgroups of adults.Results: The review showed that in adults, cannabis use increased over the past decade overall and within sociodemographic subgroups (gender, age, race/ethnicity, income, education, marital status, urbanicity, region, pregnancy status, disability status), with greater increases in men and disabled adults. Most sources also indicated significant increases in cannabis use disorders. New analysis showed significantly greater increases in adult cannabis use and cannabis use disorder in men (p ≤ .0001); young adults (p < .05); Blacks (vs. Whites, p < .01); low income groups (p < .001); never-married p ≤ .0001), and urban residents (p < .05). In adolescents, cannabis use generally decreased, although recent increases were observed in older and non-White adolescents.Conclusion: Cannabis use and cannabis use disorder are increasing in adults, with specific sociodemographic groups at higher risk, and may be increasing in some adolescent subgroups. Studies should determine mechanisms for differential trends to provide information to policymakers and enable informed decisions on cannabis legalization and service planning.

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.

Prescription tranquilizer/sedative misuse prevalence and correlates across age cohorts in the US

BACKGROUND

Prescription tranquilizer/sedative (e.g., alprazolam, zolpidem) misuse (i.e., use in ways not intended by the prescriber or without a prescription) is understudied, with little research identifying misuse correlates. Identification of key correlates could identify subgroups more likely to engage in misuse, allowing for targeted treatment. This work examines tranquilizer/sedative use and misuse prevalence rates and misuse correlates across U.S. age cohorts, using nationally representative data.

METHODS

Data were from the 2015-16 National Survey on Drug Use and Health (n = 114,043). Analyses used design-based logistic regression for past-year tranquilizer/sedative misuse correlates across participants or those engaged in past-year use; past-month misuse correlates were also examined in those with past-year misuse.

RESULTS

Young adults (18-25 years) had the highest prevalence of past-year and past-month tranquilizer/sedative misuse, with 42.8% of those with past-year use also engaged in misuse. Mental health correlates were associated with past-year misuse, while substance use, particularly opioid misuse, was associated with both past-year and past-month misuse. Substance use correlate strength was most likely to vary by age group, with older adults (65 years and older) having fewer significant correlates overall.

CONCLUSIONS

This work highlighted young adults and those with other substance use as most likely to engage in tranquilizer/sedative misuse. In particular, those endorsing suicidality and reporting opioid misuse are a subgroup of concern, given their especially elevated rates of misuse and the increased risk for overdose imparted by tranquilizer/sedative medication. Workplace-based interventions for young adults and school-based universal prevention may be warranted to limit tranquilizer/sedative misuse in these groups.

Patterns in first and daily cigarette initiation among youth and young adults from 2002 to 2015

This study’s objective was to describe long-term trends and patterns in first cigarette use (cigarette initiation) and daily cigarette use (daily initiation) among youth and young adults in the U.S. We used cross-sectional survey data from the National Survey on Drug Use and Health, 2002–2015, to estimate annual incidence of first cigarette use (N = 270,556) and first daily cigarette use (N = 373,464) for each year by age groups, race/ethnicity and gender, examining trends over time and the average annual change in initiation for each group. Several clear patterns emerged: 1) cigarette initiation and daily initiation significantly decreased over time among those aged 12–14 and 15–17 and these trends were consistent among nearly all racial/ethnic and gender subgroups; 2) among 18–21 year olds, cigarette initiation sharply increased through 2009, surpassing rates among 15–17 year olds, and sharply declined through 2015 while remaining higher than rates among the younger group, and this trend was consistent for almost all racial/ethnic subgroups; 3) daily initiation for those aged 18–21 significantly declined, and this was significant among most subgroups 4) there was no change in cigarette initiation and daily initiation for 22–25 year olds overall and most subgroups; 5) there was a significant increase in cigarette initiation for 22–25 year old Hispanics males and daily initiation for 22–25 year old males. This study provides a comprehensive look at trends in cigarette and daily initiation among U.S. youth and young adults. Despite notable declines in smoking initiation among youth and young adult populations over the last two decades, targeted prevention and policy efforts are needed for subgroups at higher risk, including young adults and Hispanic males.

Declines in prevalence of adolescent substance use disorders and delinquent behaviors in the USA: a unitary trend?

BACKGROUND

Downward trends in a number of adolescent risk behaviors including violence, crime, and drug use have been observed in the USA in recent years. It is unknown whether these are separate trends or whether they might relate to a general reduction in propensity to engage in such behaviors. Our objectives were to quantify trends in substance use disorders (SUDs) and delinquent behaviors over the 2003-2014 period and to determine whether they might reflect a single trend in an Externalizing-like trait.

METHODS

We analyzed data from 12 to 17 year old participants from the National Survey on Drug Use and Health, a representative survey of the household dwelling population of the USA, across the 2003-2014 period (N = 210 599). Outcomes included past-year prevalence of six categories of substance use disorder and six categories of delinquent behavior.

RESULTS

Trend analysis suggested a net decline of 49% in mean number of SUDs and a 34% decline in delinquent behaviors over the 12-year period. Item Response Theory models were consistent with the interpretation that declines in each set of outcomes could be attributed to changes in mean levels of a latent, Externalizing-like trait.

CONCLUSIONS

Our findings suggest that declines in SUDs and some delinquent behaviors reflect a single trend related to an Externalizing-like trait. Identifying the factors contributing to this trend may facilitate continued improvement across a spectrum of adolescent risk behaviors.

US Epidemiology of Cannabis Use and Associated Problems

This review provides an overview of the changing US epidemiology of cannabis use and associated problems. Adults and adolescents increasingly view cannabis as harmless, and some can use cannabis without harm. However, potential problems include harms from prenatal exposure and unintentional childhood exposure; decline in educational or occupational functioning after early adolescent use, and in adulthood, impaired driving and vehicle crashes; cannabis use disorders (CUD), cannabis withdrawal, and psychiatric comorbidity. Evidence suggests national increases in cannabis potency, prenatal and unintentional childhood exposure; and in adults, increased use, CUD, cannabis-related emergency room visits, and fatal vehicle crashes. Twenty-nine states have medical marijuana laws (MMLs) and of these, 8 have recreational marijuana laws (RMLs). Many studies indicate that MMLs or their specific provisions did not increase adolescent cannabis use. However, the more limited literature suggests that MMLs have led to increased cannabis potency, unintentional childhood exposures, adult cannabis use, and adult CUD. Ecological-level studies suggest that MMLs have led to substitution of cannabis for opioids, and also possibly for psychiatric medications. Much remains to be determined about cannabis trends and the role of MMLs and RMLs in these trends. The public, health professionals, and policy makers would benefit from education about the risks of cannabis use, the increases in such risks, and the role of marijuana laws in these increases.

Did the dependent coverage expansion increase risky substance use among young adults?

BACKGROUND

The dependent coverage expansion (DCE) enacted through the Affordable Care Act increased health insurance coverage among young adults. Increasing insurance coverage in this age group has the potential for unintended consequences on risky substance use.

METHODS

Repeated cross-sectional surveys were used to compare change in substance use during the period the DCE was implemented in the 19-25year old target age group (Pre-DCE n=15,772, Post-DCE n=22,719) with contemporaneous change in a slightly older age group that was not targeted by the policy (Pre-DCE=19,851, Post-DCE n=28,157). Outcomes include 11 measures of alcohol, illicit drug and cigarette use. Statistical controls were included for demographic and socioeconomic factors and for early initiation of substance use to adjust for historical trends in developmental trajectories.

RESULTS

Risky substance use decreased in young adults relative to the older age group over the period that the DCE was implemented. However, statistical adjustment for initiation of substance use prior to age 18, which is prior to exposure to the DCE, accounted for the differences between the age groups. In adjusted models, associations between the DCE and substance use outcomes range from 0.96 to 1.08 with p-values ranging from 0.330 to 0.963.

CONCLUSIONS

Historical trends in initiation of substance use prior to age 18, not the DCE, account for change in risky substance use among 19-25year olds relative to 26-34year olds. The evidence does not support the suggestion that health insurance coverage would increase risky substance use among young adults.

National Trends in Substance Use and Use Disorders Among Youth

OBJECTIVE

To examine trends in the 12-month prevalence of patterns of substance use and substance use disorders (SUDs) among US youth during 2002 through 2014.

METHOD

Data were from 288,300 persons 12 to 17 years old who participated in the 2002 to 2014 National Surveys on Drug Use and Health. Descriptive analyses and bivariable and multivariable logistic regressions were applied.

RESULTS

During 2002 through 2014, among US youth, the 12-month prevalence of any substance use decreased by 27.1% (from 43.2% to 31.5%); among youth users, the 12-month prevalence of SUDs decreased by 28.9% (from 27.0% to 19.2%), and the ratio of substance dependence to abuse decreased from 2.2 to 1.6. Multiple substance use was common and was associated with SUDs. During 2002 through 2014, the prevalence of using marijuana and alcohol only, using marijuana only, and having marijuana use disorders only increased, whereas most other trends were downward. Increases in age at first substance use were associated with downward trends in any substance use. Upward trends in age at first substance use, youth and parental strong disapproval of cigarette use, and youths' seatbelt-wearing prevalence and downward trends in substance use patterns were associated with the downward trend in SUDs among youth users.

CONCLUSION

The 12-month prevalence of any substance use among youth and SUDs among youth users decreased during 2002 through 2014. Postponing age at first use of any substance is critical among youth in the United States. Future research is needed to better understand the interrelations between specific risk and protective factors, age at first substance use, substance use patterns, and SUDs among youth users.

Are adolescents more vulnerable to the harmful effects of cannabis than adults? A placebo-controlled study in human males

Preclinical research demonstrates that cannabinoids have differing effects in adolescent and adult animals. Whether these findings translate to humans has not yet been investigated. Here we believe we conducted the first study to compare the acute effects of cannabis in human adolescent (n=20; 16-17 years old) and adult (n=20; 24-28 years old) male cannabis users, in a placebo-controlled, double-blind cross-over design. After inhaling vaporized active or placebo cannabis, participants completed tasks assessing spatial working memory, episodic memory and response inhibition, alongside measures of blood pressure and heart rate, psychotomimetic symptoms and subjective drug effects (for example, 'stoned', 'want to have cannabis'). Results showed that on active cannabis, adolescents felt less stoned and reported fewer psychotomimetic symptoms than adults. Further, adults but not adolescents were more anxious and less alert during the active cannabis session (both pre- and post-drug administration). Following cannabis, cognitive impairment (reaction time on spatial working memory and prose recall following a delay) was greater in adults than adolescents. By contrast, cannabis impaired response inhibition accuracy in adolescents but not in adults. Moreover, following drug administration, the adolescents did not show satiety; instead they wanted more cannabis regardless of whether they had taken active or placebo cannabis, while the opposite was seen for adults. These contrasting profiles of adolescent resilience (blunted subjective, memory, physiological and psychotomimetic effects) and vulnerability (lack of satiety, impaired inhibitory processes) show some degree of translation from preclinical findings, and may contribute to escalated cannabis use by human adolescents.

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

PURPOSE

As marijuana laws have become more permissive, survey data on adolescents in the United States have shown an increase in marijuana-specific risk factors, particularly in the proportion of youth who do not perceive marijuana use as harmful. Prevalence of marijuana use among youth, however, has changed little. Using representative data from Washington State, which has legalized medical and nonmedical marijuana for adults, we examined two competing hypotheses to account for this divergence in population trends.

METHODS

Data were from 2000 to 2014 biennial Washington State surveys of 10th-grade students. First, we assessed whether associations between marijuana use and marijuana-specific risk factors have weakened over time. Second, we examined whether decreases in alcohol and cigarette use can account for the lack of expected increase in marijuana use prevalence.

RESULTS

Despite stability in marijuana use prevalence, there were increases in marijuana-specific risk factors of low perceived harm, youth favorable attitudes about use, and perceived community attitudes favorable to use. Associations between marijuana use and marijuana use predictors varied little across time; if anything, the positive association between low perceived harm and marijuana use grew stronger. Decreases in prevalence of alcohol and cigarette use largely accounted for stability in marijuana use during a period when marijuana risk factors increased.

CONCLUSIONS

Decreases in other types of substance use or in the underlying, common risk for substance use may have mitigated effects of increases in marijuana-specific risk factors.