Adolescent Marijuana Use in the United States and Structural Breaks: An Age-Period-Cohort Analysis, 1991-2018

To investigate temporal patterns, sociodemographic gradients, and structural breaks in adolescent marijuana use in the United States from 1991 to 2018, we used hierarchical age-period-cohort logistic regression models to distinguish temporal effects of marijuana use among 8th, 10th, and 12th graders from 28 waves of the Monitoring the Future survey (1991-2018). Structural breaks in period effects were further detected via a dynamic-programing-based method. Net of other effects, we found a clear age-related increase in the probability of marijuana use (10.46%, 23.17%, and 31.19% for 8th, 10th, and 12th graders, respectively). Period effects showed a substantial increase over time (from 16.23% in 2006 to 26.38% in 2018), while cohort effects remained stable throughout the study period. Risk of adolescent marijuana use varied by sex, racial group, family status, and parental education. Significant structural breaks during 1995-1996, 2006-2008, and 2011-2013 were identified in different subpopulations. A steady increase in marijuana use among adolescents during the latter years of this time period was identified. Adolescents who were male, were non-Black, lived in nonintact families, and had less educated parents were especially at risk of marijuana usage. Trends in adolescent marijuana use changed significantly during times of economic crisis.

Perceptions of U.S. and Canadian Cannabis Package Warnings Among U.S. Adults

BACKGROUND

Cannabis warning labels can communicate risks, but there is little research on warning perceptions and differences by product type.

METHODS

In a 2019 online survey, 1,000 U.S. adults (500 cannabis users and 500 cannabis non-users who used tobacco) were randomly assigned to view no warning or one of four U.S. or Canadian warnings displayed on images of packaging for dried flower or edible cannabis. The warnings described cannabis risks related to psychosis, addiction, lack of FDA oversight, and impaired driving. We used linear regression to examine perceptions of warnings and product harm as a function of product type (dried or edible) and warning. We examined which warning participants selected as most effective for discouraging youth use and impaired driving.

RESULTS

Participants found the addiction warning (cannabis users: B = -1.04, p < 0.001; cannabis non-users: B = 1.17, p < 0.001) and psychosis warning (users: B = -0.65, p < 0.05; non-users: B = -0.71, p < 0.05) less believable than the driving warning but indicated that they learned more from the psychosis warning than the driving warning (users: B = 0.88, p < 0.01; non-users (B = 1.60, p < 0.001). Participants viewing any warning considered smoking cannabis to be more harmful than those viewing no warning (all p < 0.05). The psychosis warning was most frequently selected as the best warning for discouraging youth use.

CONCLUSIONS

Warnings have the potential to educate consumers and impact cannabis harm perceptions. Warnings have similar effects across product types, potentially eliminating the need for product type-specific warnings. The association of cannabis use with risk for psychosis, a topic addressed in Canadian warnings, could be a useful topic of focus in U.S. warnings.

Longitudinal associations between amygdala reactivity and cannabis use in a large sample of adolescents

RATIONALE

The amygdala is a key brain structure to study in relation to cannabis use as reflected by its high-density of cannabinoid receptors and functional reactivity to processes relevant to drug use. Previously, we identified a correlation between cannabis use in early adolescence and amygdala hyper-reactivity to angry faces (Spechler et al. 2015).

OBJECTIVES

Here, we leveraged the longitudinal aspect of the same dataset (the IMAGEN study) to determine (1) if amygdala hyper-reactivity predicts future cannabis use and (2) if amygdala reactivity is affected by prolonged cannabis exposure during adolescence.

METHODS

First, linear regressions predicted the level of cannabis use by age 19 using amygdala reactivity to angry faces measured at age 14 prior to cannabis exposure in a sample of 1119 participants. Next, we evaluated the time course of amygdala functional development from age 14 to 19 for angry face processing and how it might be associated with protracted cannabis use throughout this developmental window. We compared the sample from Spechler et al. 2015, the majority of whom escalated their use over the 5-year interval, to a matched sample of non-users.

RESULTS

Right amygdala reactivity to angry faces significantly predicted cannabis use 5 years later in a dose-response fashion. Cannabis-naïve adolescents demonstrated the lowest levels of amygdala reactivity. No such predictive relationship was identified for alcohol or cigarette use. Next, follow-up analyses indicated a significant group-by-time interaction for the right amygdala.

CONCLUSIONS

(1) Right amygdala hyper-reactivity is predictive of future cannabis use, and (2) protracted cannabis exposure during adolescence may alter the rate of neurotypical functional development.

Cannabis knowledge and implications for health: Considerations regarding the legalization of non-medical cannabis

Cannabis contains over a hundred of different cannabinoids, of which Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most well studied. The use of high-potency cannabis, containing high concentrations of THC and low concentrations of CBD, has been linked to adverse health outcomes, particularly for adolescents and young adults. Recently, an increase in cannabis potency has been observed in jurisdictions that legalized the sale of cannabis for non-medical purposes. Moreover, an increase of cannabis use and cannabis-related emergency treatment have also been observed in these jurisdictions. At the same time, risk perception regarding cannabis use has decreased in these populations. Trivializing language and an increased appearance of commercial cannabis in the public space may lead to a generalized underestimation of the risks of cannabis use. New regulation models principally focus on the creation of a legal cannabis market economy, the diversion of profits from illegal markets, and the reduction of costs associated with prohibition. However, an approach that specifically focuses on the rights to the health and safety of the individual should be considered in order to reduce the risks associated with cannabis legalization. Such an approach should promote and protect individual and social health and safety, establish a strict quality control of legal cannabis products regulated according to THC and CBD content, and eliminate all sorts of incentives to use, thus providing a more consistent, sustainable, and ethical framework for the legalization of non-medical cannabis use.

Incidental finding of age and time disorientation in a clinical sample of patients with schizophrenia: Findings from a short term follow up survey regarding cannabis use

Age disorientation has been described in a subtype of patients with schizophrenia. The current article reports on an incidental finding from our survey study on patterns of cannabis use pre-post legalization in patients with schizophrenia. For the purpose of the survey study, patients were asked to fill out a total of 41 survey questions. The same participants were contacted over the phone 8 weeks post-legalization. Responses to the survey questions were consistent pre- and post-legalization except for four items which required estimation of time/age. This incidental finding highlights the need for further exploration of this phenomenon by future studies.

Digital media use and subsequent cannabis and tobacco product use initiation among adolescents

BACKGROUND

Digital media engagement, such as browsing the internet or social media posting, may be associated with cannabis and tobacco product use initiation among adolescents. Whether certain digital media exposure confers greater - or reduced - risk for specific cannabis or tobacco products is unknown.

METHODS

Adolescents completed surveys on digital media and substance use every 6 months from 2015 to 2017 (4 waves). Self-reported digital media use (14 items) was classified into six subcategories (e.g., "social media posting," "reading news/articles & browsing photos"). Random-effect repeated-measures regression models examined the association of exposure to each digital media subcategory with subsequent cannabis or tobacco product use initiation in the next 6 months, among baseline cannabis and tobacco never-users (n = 1841; n = 1558, respectively).

RESULTS

High frequency digital media use (multiple times/day) of "social media posting" (vs. no high frequency use; OR = 1.95; 95%CI:1.20-3.17) and "checking in" (OR = 1.71; 95%CI:1.23-2.38) was associated with greater odds of any cannabis product use initiation 6 months later. "Reading news/articles & browsing photos" was associated with decreased odds of initiation (OR = 0.52; 95%CI:0.34-0.79). "Checking in" and "reading news/articles & browsing photos" were similarly associated with any tobacco use initiation. "Chatting and shopping" was associated with greater odds (OR = 4.63; 95%CI:1.53-14.06) of e-cigarette initiation, but not of other product use initiation.

CONCLUSIONS

Some subcategories of digital media use conferred increased odds, others conferred reduced odds, and others were not associated with cannabis and tobacco use initiation. Research exploring mechanisms that put users of specific digital media at greater risk for substance use initiation is warranted.

Facing the option for the legalisation of cannabis use and supply in New Zealand: An overview of relevant evidence, concepts and considerations

ISSUES

Non-medical cannabis policies are changing, including towards legalisation-with-regulation frameworks. New Zealand will hold a public referendum on cannabis legalisation in 2020. We reviewed data on cannabis use and health/social harms; policy reform options; experiences with and outcomes of reforms elsewhere; and other relevant considerations towards informing policy choices in the upcoming referendum.

APPROACH

Relevant epidemiological, health, social, criminal justice and policy studies and data were identified and comprehensively reviewed.

KEY FINDINGS

Cannabis use is common (including in New Zealand) and associated with risks for health and social harms, mainly concentrated in young users; key harms are attributable to criminalisation. 'Decriminalisation' reforms have produced ambivalent results. Existing cannabis legalisation frameworks vary considerably in main parameters. Legalisation offers some distinct advantages, for example regulated use, products and user education, yet outcomes depend on essential regulation parameters, including commercialisation, and policy ecologies. While major changes in use are not observed, legalisation experiences are inconclusive to date, including mixed health and social outcomes, with select harms increasing and resilient illegal markets. It is unclear whether legalisation reduces cannabis exposure or social harms (e.g. from enforcement) for youth.

IMPLICATIONS/CONCLUSIONS

No conclusive overall evidence on the outcomes of legalisation elsewhere exists, nor is evidence easily transferable to other settings. Legalisation offers direct social justice benefits for adults, yet overall public health impacts are uncertain. Legalisation may not categorically improve health or social outcomes for youth. Legalisation remains a well-intended, while experimental policy option towards more measured and sensible cannabis control and overall greater policy coherence, requiring close monitoring and possible adjustments depending on setting-specific outcomes.

On the discounting of cannabis and money: Sensitivity to magnitude vs. delay

BACKGROUND

While using most drugs of abuse is associated with higher than control rates of delay discounting, cannabis use may be the exception. As such, between-commodity differences in delay discounting (i.e., money vs. cannabis) have not been thoroughly examined. We examined these between-commodity differences using modern analytic techniques to disentangle effects of subjects' sensitivity to magnitude and delay as potential drivers of any obtained delay discounting rate differences.

METHOD

; Fifty-eight college students (n = 33 cannabis users, n = 25 non-users) completed a monetary delay discounting task - with the cannabis users completing the cannabis problems questionnaire as well a delay discounting of cannabis task- in an on-campus laboratory.

RESULTS

Responding between groups differed on the cannabis problems questionnaire, but not on delay discounting of monetary outcomes. Cannabis users, however, discounted cannabis at higher rates than money. Multilevel logistic regression revealed that these between-commodity delay discounting differences were due to subjects' differential sensitivity to the magnitude of these two commodities, rather than sensitivity to delay to receiving these commodities.

CONCLUSIONS

Although differences in delay discounting rate were not obtained between students that did and did not use cannabis, cannabis users did discount cannabis at higher rates than they did money - suggesting considerable generality of the between commodity differences in delay discounting obtained elsewhere. The current between-commodity delay discounting differences appear to be driven by differential sensitivity to the reinforcer magnitudes presented in each task - a finding that awaits replication across other comparisons before statements about generality can be made.

Blunted highs: Pharmacodynamic and behavioral models of cannabis tolerance

Acute exposure to cannabis comes with neurocognitive impairment, leading to increased risk of human error and injury. Evidence however indicates that such acute effects are less prominent in chronic users, suggesting cannabis tolerance. Models of cannabis tolerance stress the importance of neurobiological or behavioral adaptations following repeated cannabis exposure. The pharmacodynamic model relates neuroadaptive changes in the brain to a blunted response to cannabis. Downregulation of CB1 receptors in chronic cannabis users has been associated with a normalization of dopaminergic output from the ventral tegmental area to the mesolimbic circuit, and a reduction of impairment during acute cannabis exposure. Such neuroadaptions are absent in occasional users, who show strong increments of dopamine and glutamate levels in the striatum, a loss of functional connectivity within the mesolimbic circuit and neurocognitive impairments when exposed to cannabis. Evidence for a behavioral model of cannabis tolerance that poses that users can have volitional control to overcome functional impairment during cannabis intoxication is relatively weak, and at best shows limited control over a limited number of behavioral functions. Cannabis tolerance is most likely to occur in users that consume high doses of cannabis continuously, at a high pace, for a prolonged period of time. Knowledge on frequency, dose and duration of cannabis use that is needed to achieve, maintain or lessen tolerance however is very limited, but will be of importance in the context of cannabis therapeutics and in legal settings when evaluating the impact of cannabis exposure on human function.

Complex cannabis use patterns: Associations with cannabis consequences and cannabis use disorder symptomatology

BACKGROUND

Historically, cannabis researchers have assumed a single mode and product of cannabis (e.g., smoking plant). However, patterns of use, products (e.g., concentrates, edibles), and modes (e.g. blunts, vaporizers) are diversifying. This study sought to: 1) classify cannabis users into groups based on their use of the full range of cannabis products, and 2) examine user group differences on demographics, cannabis consequences and cannabis use disorder (CUD) symptomatology.

METHODS

In a sample of college students (data collected in Fall 2017), who used cannabis in the past year (N = 1390), latent class analysis (LCA) was used to characterize cannabis users. We then added demographic characteristics, cannabis consequences, and CUD symptomatology scores separately to LCA models to examine class differences.

RESULTS

Five unique classes emerged: high-frequency all-product users, high-frequency plant/moderate-frequency edible and concentrate users, low-frequency plant users, moderate-frequency plant and edible users, and low-frequency edible users. Demographic characteristics, cannabis consequences, and CUD symptomatology differed across classes characterized by frequency as well as product.

CONCLUSIONS

Results reflect the increasing variety of cannabis products, modes, and use patterns among college students. In this sample, frequency of use remains a strong predictor of cannabis-related consequences, in addition to type of product. As variation in cannabis use patterns continue to evolve, it is essential for researchers to conduct comprehensive assessments.

Preconception Marijuana Use in Rhode Island: Rates, Demographics, and Psychosocial Correlates

INTRODUCTION

Rates of marijuana use in Rhode Island (RI) exceed the national average; prevalence during preconception and characteristics of users remain unknown.

METHODS

Prevalence of marijuana use in the 3 months preconception was assessed by a RI-based telephone survey of a diverse, low-income sample of pregnant women (n=1683). Sociodemographic characteristics, substance use, and mental health were compared between preconception marijuana users, tobacco users and non-users.

RESULTS

25.1% of respondents reported using marijuana during preconception. Marijuana users were younger, poorer, and less educated than non-users (ps<0.001) and more likely to report alcohol use and mental illness (ps<0.001). Marijuana users were younger with fewer children than tobacco-only users (ps<0.001).

CONCLUSIONS

Rates of preconception marijuana use in RI exceed national rates of prenatal use. Preconception marijuana users have a distinct sociodemographic profile, with higher rates of concurrent mental health conditions and alcohol use. Understanding this characterization enables targeted screening and interventions.

Adolescent E-cigarette use trajectories and subsequent alcohol and marijuana use

INTRODUCTION

As electronic cigarette (e-cigarette) use has become more prevalent among adolescents, there is a growing body of evidence linking e-cigarette use to the initiation of other substances. Whether there is a threshold level of e-cigarette use that is predictive of other substance use is unknown. The current study examines patterns of e-cigarette use over time and determines whether different patterns of early adolescent e-cigarette use are concurrently and prospectively associated with alcohol and marijuana use in late adolescence.

METHOD

Eight hundred and one adolescents (13-15 years old at baseline recruitment) completed five on-line surveys over a two-year period. Latent class growth analysis was used to model different developmental courses of e-cigarette, alcohol (drinking to intoxication), and marijuana use. Logistic regression was used to test the association between e-cigarette use trajectory patterns and alcohol and marijuana use trajectories.

RESULTS

Three developmental courses of e-cigarette use were identified: 1) high and increasing, 2) low and increasing, and 3) never. Compared to adolescents who had never used e-cigarettes, those in the other two groups were more likely to have been intoxicated and to be in the moderate and increasing marijuana use group.

CONCLUSION

Both high and low levels of e-cigarette use patterns are associated with increasing use of other substances (alcohol and marijuana use) over time. Findings highlight the need for early intervention and prevention of e-cigarette use among adolescents.

Does Unit-Dose Packaging Influence Understanding of Serving Size Information for Cannabis Edibles?

OBJECTIVE

Edible cannabis products have increased in popularity, particularly in jurisdictions that have legalized nonmedical cannabis. Rates of adverse events from cannabis edibles have also increased, in part because of difficulties identifying and titrating tetrahydrocannabinol (THC) levels. The current study tested whether packaging cannabis in separate units enhances consumer understanding of serving sizes.

METHOD

An experimental task was conducted as part of the 2018 International Cannabis Policy Study online survey. Participants were recruited from the Nielsen Global Insights Consumer Panel. A total of 26,894 participants (61.5% female) ages 16-65 years from Canada and the United States were randomly assigned to view a cannabis brownie packaged according to one of three conditions: (a) multiserving edible ("control condition"), (b) single-serving edible, and (c) single-serving edible packaged separately ("unit-dose packaging"). Participants were asked to identify a standard serving based on information on the product label. Logistic regression was used to test the influence of packaging condition on the likelihood of a correct response, adjusting for key covariates.

RESULTS

Compared with the multiserving edible control (50.6%), participants were significantly more likely to correctly identify the serving size in the single-serving edible condition (55.3%; adjusted odds ratio = 1.22, CI [1.15, 1.29], p < .001) and the unit-dose packaging condition (54.3%; adjusted odds ratio = 1.17, CI [1.10, 1.24], p < .001).

CONCLUSIONS

Packaging in which each product unit contained one dose of THC enhanced consumers' ability to identify how much of a product constitutes a standard serving or dose. Packaging products as individual doses eliminates the need for mental math and could reduce the risk of accidental overconsumption of cannabis.

Long-Term Effects of Early Adolescent Marijuana Use on Attentional and Inhibitory Control

OBJECTIVE

This study sought to examine the prospective effects of early adolescent marijuana use on late adolescent attentional and inhibitory control. Alcohol use, antisocial problems, and gender were included as statistical control variables.

METHOD

The community sample of 387 adolescents and a caregiver was drawn from a longitudinal study of adolescent substance use that included nine annual assessments. Adolescents were eligible if they were between ages 11 and 12 at recruitment and did not have any disabilities that would preclude them from either understanding or completing the assessment. The sample was evenly split on gender (55% female) and was predominantly non-Hispanic White (83.16%) or African American (9.07%). Attentional and inhibitory control were assessed using parent and adolescent self-reports on the Early Adolescent Temperament Questionnaire-Revised and the Adult Temperament Questionnaire.

RESULTS

Hypotheses were tested using structural equation modeling. High levels of early marijuana use at ages 12-14 significantly predicted low levels of adolescent attentional control at ages 18-21 (β = -.20, p < .05), above and beyond early attentional control, early alcohol use, and antisocial problems.

CONCLUSIONS

Findings suggest that marijuana use may adversely affect cognitive development, especially during the sensitive period of early adolescence. Results emphasize the need for further prospective work to investigate relationships between early adolescent marijuana use and the development of executive functioning.

Trends in Reported Marijuana Vaping Among US Adolescents, 2017-2019

This national survey study uses Monitoring the Future data to characterize trends in the prevalence of marijuana vaping in 2017, 2018, and 2019 among 8th, 10th, and 12th graders.

Self-reported Marijuana Use in Electronic Cigarettes Among US Youth, 2017 to 2018

This population epidemiology study uses data from the National Youth Tobacco Survey to assess trends in self-reported use of marijuana in electronic cigarettes among US middle school and high school students from 2017 to 2018.

Trends in the sequence of first alcohol, cannabis and cigarette use in Australia, 2001-2016

BACKGROUND

Recent analyses of data from the US found that young people were increasingly engaging in cannabis use before alcohol and cigarettes. These shifts are important for public health, but it is not clear whether such trends extend beyond the US. The aim of this study is to examine whether and how the age and sequencing of initiation into alcohol, cannabis and cigarette use has changed in Australia since the early 2000s.

METHODS

Data came from six waves of the Australian National Drug Strategy Household Survey, spanning 2001-2016. We used data from 18 to 21 year-olds (n = 6849) and examined trends in the age at first use for each of the three substances plus any changes in the order of initiation.

RESULTS

The mean age of initiation increased steadily for all three substances (e.g. from 14.9 in 2001 to 16.4 in 2016 for alcohol), while the prevalence of any use declined. There were some changes in ordering of use. For example, in 2001, 62 % of respondents who used both cigarettes and cannabis had first used cigarettes at an earlier age than cannabis, compared with 41 % in 2016. Young people who used both alcohol and cannabis remained more likely to try alcohol before cannabis across the study period.

CONCLUSIONS

Our results partly replicated US findings, with differences potentially reflecting the substantially different environment around these substances in the US compared to Australia. The age of initiation for alcohol, cigarette and cannabis use in Australia has increased sharply over the past 15 years.

A History of United States Cannabis Law

Perhaps the best way to understand early-Twenty-First Century state and federal cannabis law in the United States is to examine the relevant history. Justice Oliver Wendell Holmes, Jr.'s statement is apropos: "[A] page of history is worth a volume of logic." This article begins by discussing the early history of cannabis and its uses. Next, the article examines the first state and federal marijuana laws. After a brief comparison of alcohol prohibition to cannabis prohibition, this article addresses cannabis laws from the 1920s to the early 1950s. Then, the article takes up the reorganization of the federal drug regulatory bureaucracy since its inception. Addressing the current era of cannabis laws and regulations, this article recounts how marijuana became a Schedule I drug. The discussion then turns to changing social attitudes towards cannabis as reflected in presidential politics and popular culture. Starting with the late-1990s, this article describes the development of state and federal cannabis laws and policies up to the present day.

Cannabis use and physical activity among 89,777 adolescents aged 12-15 years from 21 low- and middle-income countries

BACKGROUND

Cannabis legalization and use are increasing globally, however, little is known about associations between cannabis use and other health behaviors, such as physical activity (PA). Importantly, the extent to which cannabis use is associated with PA in adolescents is yet to be explored in low- and middle-income countries (LMICs), where there may be unique sociodemographic and environmental characteristics compared with high-income countries. Therefore, this study examined the association between PA and cannabis use among adolescents in 21 LMICs using data from the 2010-2016 Global School-based Student Health Survey.

METHODS

A multivariable logistic regression analysis was performed among a final sample of 89,777 adolescents (49.2% females) aged 12-15 years with a mean (SD) age of 13.7 (0.9) years.

RESULTS

The overall prevalence of past (i.e., in lifetime but not in past 30 days) and current (in past 30 days) cannabis use were 1.0% and 2.9% respectively, while the prevalence of adequate PA in the past week (7 days/week of 60 min of PA) was 16.6%. The prevalence of adequate levels of PA in past and current cannabis use was 7.3% and 6.9%, respectively. Current and past cannabis use (vs. never) were associated with a significant 0.62 (95% CI = 0.41-0.94) and 0.43 (95%CI = 0.30-0.63) times lower odds for achieving adequate levels of PA, respectively.

CONCLUSION

The results underscore the high prevalence of low PA among adolescents in LMICs, and emphasize the need to understand behavioral factors that may affect PA levels, such as cannabis use, when designing interventions to improve health.

Trends in cannabis use among immigrants in the United States, 2002-2017: Evidence from two national surveys

BACKGROUND AND AIMS

Findings from recent studies suggest that, among the general population of adults, the prevalence of cannabis use has increased over the last decade in the United States (US). And yet, there is much we do not know regarding the trends in cannabis use among immigrants. We address this important shortcoming by examining data on immigrants vis-à-vis US-born individuals using two national surveys.

METHODS

We examine trend data from the National Epidemiologic Study on Alcohol and Related Conditions (NESARC, 2001-2013) and the National Survey on Drug Use and Health's Restricted Data Analysis System (NSDUH, 2002-2017). Main outcomes were past year cannabis use and cannabis use disorder with survey adjusted prevalence estimates generated for immigrants and US-born individuals.

RESULTS

In the NESARC, significant increases in the past year prevalence of cannabis use were observed both among US-born (2001-2002: 4.53%, 2012-2013: 10.74%) and immigrant participants (2001-2002: 1.67%, 2012-2013: 3.32%). We also found significant increases among immigrants arriving before age 12 and among immigrants from Latin America and Europe. In the NSDUH, we observed a significantly higher prevalence of cannabis use in 2016-2017 (6.3%) when compared to 2002-2003 (4.4%).

CONCLUSIONS

Findings make clear that cannabis use among US-born individuals has consistently been higher than that of immigrants since the early 2000s. However, while rates of cannabis use have declined among US-born adolescents in recent years, the prevalence of cannabis use has remained stable among immigrant adolescents. At the same time, cannabis use increased two-fold among both US-born and immigrant adults.

Weeding Out the Problem: The Impact of Preoperative Cannabinoid Use on Pain in the Perioperative Period

BACKGROUND

The recreational and medical use of cannabinoids has been increasing. While most studies and reviews have focused on the role of cannabinoids in the management of acute pain, no study has examined the postoperative outcomes of surgical candidates who are on cannabinoids preoperatively. This retrospective cohort study examined the impact of preoperative cannabinoid use on postoperative pain scores and pain-related outcomes in patients undergoing major orthopedic surgery.

METHODS

Outcomes of patients who had major orthopedic surgery at our hospital between April 1, 2015 and June 30, 2017 were reviewed. Data were obtained from Networked Online Processing of Acute Pain Information, a locally developed database for our Acute Pain Service. Propensity score matching was used to balance baselines variables including age, sex, type of surgery, history of depression or anxiety, and perioperative use of regional anesthesia between patients who reported use of cannabinoids and those not on this substance. Intensity of pain with movement in the early postoperative period (defined as up to 36 hours after surgery) was the primary outcome of this study. The secondary outcomes (all in early postoperative period) were pain at rest, opioid consumption, incidence of pruritus, nausea and vomiting, sedation, delirium, constipation, impairment of sleep and physical activity, patient satisfaction with analgesia, and the length of Acute Pain Service follow-up.

RESULTS

A total of 3793 patients were included in the study. Of these, 155 patients were identified as being on cannabinoids for recreational or medical indications in the preoperative period. After propensity score matching, we compared data from 155 patients who were on cannabinoids and 155 patients who were not on cannabinoids. Patients who were on preoperative cannabinoids had higher pain numerical rating score (median [25th, 75th percentiles]) at rest (5.0 [3.0, 6.1] vs 3.0 [2.0, 5.5], P = .010) and with movement (8.0 [6.0, 9.0] vs 7.0 [3.5, 8.5], P = .003), and a higher incidence of moderate-to-severe pain at rest (62.3% vs 45.5%, respectively, P = .004; odds ratio, 1.98; 95% CI, 1.25-3.14) and with movement (85.7% vs 75.2% respectively, P = .021; odds ratio, 1.98; 95% CI, 1.10-3.57) in the early postoperative period compared to patients who were not on cannabinoids. There was also a higher incidence of sleep interruption in the early postoperative period for patients who used cannabinoids.

CONCLUSIONS

This retrospective study with propensity-matched cohorts showed that cannabinoid use was associated with higher pain scores and a poorer quality of sleep in the early postoperative period in patients undergoing major orthopedic surgery.

Alcohol, tobacco, and marijuana consumption is associated with increased odds of same-day substance co- and tri-use

BACKGROUND

Little is known about event-level patterns of marijuana co- or tri-use with alcohol and tobacco. Thus, the study goal was to examine patterns of same-day alcohol, cigarette, and marijuana co- and tri-use at the individual level in non-treatment-seeking alcohol users.

METHODS

Participants (N = 551) completed an in-person interview for alcohol, cigarette, and marijuana use over the previous 30 days, and the event-level substance use patterns of n = 179 participants who reported using each of these substances at least once per month were analyzed.

RESULTS

The use of alcohol, marijuana, or cigarettes independently increased the probability of subsequent, simultaneous co-use of one of the two remaining substances. The co-use of alcohol with cigarettes and marijuana with cigarettes produced generally additive effects on the odds of same day tri-use of marijuana and alcohol, respectively. Conversely, the co-use of alcohol and marijuana produced sub-additive effects on likelihood of cigarette use. Sex moderated several of the observed patterns of co- and tri-use: the relationship between alcohol or cigarette use predicting marijuana co-use was stronger in men, whereas the observed additive relationships between drug co-use leading to tri-use was stronger in women.

CONCLUSIONS

The presented results may aid in the understanding of how simultaneous co-use of marijuana with alcohol and/or tobacco relates to the etiology, maintenance, and treatment of comorbid and trimorbid substance use disorder. Replication and extension of the results in treatment seeking populations using more fine-grained analysis approaches, e.g. ecological momentary assessment, is needed.

Contribution of cannabis-related cues to concurrent reinforcer choice in humans

BACKGROUND

Drug-related cues play a critical role in the development and persistence of substance use disorder. Few human laboratory studies have evaluated how these cues contribute to decisions between concurrently presented reinforcers, and none have examined the specific role of cannabis cues. This study evaluated the contribution of cannabis-related cues to concurrent monetary reinforcer choice in humans.

METHODS

Participants with a cannabis use history (i.e., use in the past two weeks and 50 or more lifetime uses; n = 71) and controls without this history (i.e., 5 or less lifetime uses; n = 79) were recruited using Amazon Mechanical Turk. A cued concurrent choice task was used in which cannabis trials presented two cues (one cannabis and one neutral) side-by-side followed by concurrent monetary offers below each image. The primary dependent measure was choice for cannabis-cued monetary reinforcers on equal value trials. Secondary analyses evaluated individual difference variables related to choice bias.

RESULTS

Participants in the cannabis group showed a significant bias for cannabis-cued choices (mean 76.0%) whereas participants in the control group showed a significant bias against cannabis-cued choices (mean 30.3%). Reaction times on cannabis trials were faster than neutral filler trials and did not differ by group. Cannabis-cued choice was significantly associated with more frequent cannabis use (r = .44), higher cannabis demand intensity (r = .28), and lower cannabis elasticity (r = -.30).

CONCLUSIONS

These findings suggest that cannabis-related cues can influence reinforcer choice and potentially promote disadvantageous decision-making related to non-drug reinforcers.

Exploring the relationship between polygenic risk for cannabis use, peer cannabis use and the longitudinal course of cannabis involvement

BACKGROUND AND AIMS

Few studies have explored how polygenic propensity to cannabis use unfolds across development, and no studies have yet examined this question in the context of environmental contributions such as peer cannabis use. Outlining the factors that contribute to progression from cannabis initiation to problem use over time may ultimately provide insights into mechanisms for targeted interventions. We sought to examine the relationships between polygenic liability for cannabis use, cannabis use trajectories from ages 12-30 years and perceived peer cannabis use at ages 12-17 years.

DESIGN

Mixed-effect logistic and linear regressions were used to examine associations between polygenic risk scores, cannabis use trajectory membership and perceived peer cannabis use.

SETTING

United States.

PARTICIPANTS

From the Collaborative Study on the Genetics of Alcoholism (COGA) study, a cohort of 1167 individuals aged 12-26 years at their baseline (i.e. first) interview.

MEASUREMENTS

Key measurements included life-time cannabis use (yes/no), frequency of past 12-month cannabis use, maximum life-time frequency of cannabis use, cannabis use disorder (using DSM-5 criteria) and perceived peer cannabis use. Polygenic risk scores (PRS) were created using summary statistics from a large (n = 162 082) genome-wide association study (GWAS) of cannabis use.

FINDINGS

Three trajectories reflecting no/low (n = 844), moderate (n = 137) and high (n = 186) use were identified. PRS were significantly associated with trajectory membership [P = 0.002-0.006, maximum conditional R2  = 1.4%, odds ratios (ORs) = 1.40-1.49]. Individuals who reported that most/all of their best friends used cannabis had significantly higher PRS than those who reported that none of their friends were users [OR = 1.35, 95% confidence interval (CI) = 1.04, 1.75, P = 0.023]. Perceived peer use itself explained up to 11.3% of the variance in trajectory class membership (OR = 1.50-4.65). When peer cannabis use and the cannabis use PRS were entered into the model simultaneously, both the PRS and peer use continued to be significantly associated with class membership (P < 0.01).

CONCLUSIONS

Genetic propensity to cannabis use derived from heterogeneous samples appears to correlate with longitudinal increases in cannabis use frequency in young adults.

Preliminary results from a pilot study examining brain structure in older adult cannabis users and nonusers

Exploring associations among cannabis use, brain structure, and cognitive function in older adults offers an opportunity to observe potential harm or benefit of cannabis. This pilot study assessed structural magnetic resonance imaging in older adults who were either current cannabis users (n = 28; mean age 69.8 years, 36% female) or nonusers (n = 28; mean age 66.8 years, 61% female). Recruitment targeted users who reported at least weekly use for at least the last year, although users had 23.55 years of regular cannabis use on average (SD=19.89, range 1.5-50 years). Groups were not significantly different in terms of sex, years of education, alcohol use, or anxiety symptoms, but were significantly different in age and depression symptoms. Users and nonusers did not differ in terms of total gray or white matter volumes controlling for age and depression symptoms, but users showed greater regional volume of left putamen, lingual cortex, and rostral middle frontal cortex. No significant differences between groups were observed in performance on a brief computerized cognitive battery. These results suggest that cannabis use likely does not have a widespread impact on overall cortical volume while controlling for age.

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.

Beliefs and attitudes regarding prenatal marijuana use: Perspectives of pregnant women who report use

OBJECTIVE

With the increasingly permissive legal and social environments regarding marijuana, it is important to understand prenatal marijuana use from the perspective of women who use marijuana. Our objective was to qualitatively describe the marijuana use experiences, beliefs, and attitudes of women who used marijuana during pregnancy.

METHODS

We conducted semi-structured interviews with pregnant women who had either reported current marijuana use or had urine testing positive for marijuana. Interviews were transcribed verbatim and analyzed for patterns and themes.

RESULTS

Twenty-five pregnant women who used marijuana during their pregnancies participated in our study interviews. Main themes that emerged from the interviews were that women: 1) reported higher amounts of marijuana use prior to pregnancy and attempted to reduce their use once they realized they were pregnant; 2) used marijuana to help with nausea and appetite changes during pregnancy or to improve mood; 3) described marijuana as "natural" and "safe" compared to other substances such as alcohol, tobacco, other recreational drugs, and prescribed medications; 4) had conflicting opinions regarding whether marijuana was addictive; and 5) were uncertain but had some concerns regarding potential risks of prenatal marijuana use.

CONCLUSION

Pregnant women who used marijuana in pregnancy held contradictory beliefs about continued use; they reported trying to reduce usage and were worried about potential risks, but also felt that marijuana is more natural and safer than other substances, including prescribed medicines. These findings have implications for how practitioners address prenatal marijuana use and highlight the need for further research on developmental outcomes.

Among whom is cigarette smoking declining in the United States? The impact of cannabis use status, 2002-2015

OBJECTIVES

To 1) estimate changes in the prevalence of daily and non-daily cigarette smoking among current (past 30-day) daily, non-daily, and non-cannabis users in the United States (U.S.) population; 2) examine time trends in current (past 30-day) cigarette smoking in daily, non-daily, and non-cannabis users ages 12+ from 2002 to 2015.

METHODS

Data collected annually from the 2002 to 2015 National Survey on Drug Use and Health (NSDUH) were employed. Linear time trends of daily and non-daily cigarette smoking were assessed using logistic regression with year as the predictor.

RESULTS

In 2015, the prevalence of current (past 30-day) cigarette smoking was highest among daily (54.57%), followed by non-daily (40.17%) and non-cannabis users (15.06%). The prevalence of non-daily cigarette smoking increased among daily cannabis users from 2002 to 2015, whereas non-daily cigarette smoking declined among non-daily cannabis users and non-cannabis users from 2002 to 2015. Daily cigarette smoking declined among both cannabis users and non-users; the most rapid decline was observed among daily cannabis users, followed by non-daily and then by non-cannabis users. However, the relative magnitude of the change in prevalence of daily cigarette smoking was similar across the three cannabis groups.

CONCLUSIONS

Despite ongoing declines in cigarette smoking in the U.S., non-daily cigarette smoking is increasing among current cannabis users, a growing proportion of the U.S.

POPULATION

Daily and non-daily cigarette smoking continue to decline among those who do not use cannabis. Efforts to further tobacco control should consider novel co-use-oriented intervention strategies and outreach for the increasing population of cannabis users.

Affect and cannabis use in daily life: a review and recommendations for future research

BACKGROUND

Although cannabis is often used for the purposes of relieving negative affective states such as anxiety and depression, the associations between cannabis use and affect in daily life are unclear. Ecological momentary assessment (EMA) has been used to study these associations in individuals' natural environments, providing more ecological validity, minimizing retrospective bias, and allowing for the analysis of within-individual processes over time. This review focuses on studies that utilized EMA to examine daily-life associations of cannabis use and negative and positive affective states.

METHODS

We review the findings of the 19 articles that met inclusion criteria, including clinical and community samples.

RESULTS

Results provide equivocal evidence regarding relations between cannabis use and affect for community samples. Findings are mixed for clinical samples as well, but more consistent patterns emerge for general negative affect (NA) and anger/hostility at the momentary level; cannabis use may be more likely following increased NA and lead to decreases in NA and anger/hostility in psychiatric populations.

CONCLUSIONS

Findings support a negative reinforcement hypothesis for clinical samples in terms of general NA and anger/hostility. However, discrepancies among studies point to a need to thoroughly characterize samples, consider motives for and expectancies of use, improve quantification of cannabis use, and consider co-use with other substances. Additional design recommendations are also offered for future studies.

A Twitter-based survey on marijuana concentrate use

AIMS

The purpose of this paper is to analyze characteristics of marijuana concentrate users, describe patterns and reasons of use, and identify factors associated with daily use of concentrates among U.S.-based cannabis users recruited via a Twitter-based online survey.

METHODS

An anonymous Web-based survey was conducted in June 2017 with 687 U.S.-based cannabis users recruited via Twitter-based ads. The survey included questions about state of residence, socio-demographic characteristics, and cannabis use including marijuana concentrates. Multiple logistic regression analyses were conducted to identify characteristics associated with lifetime and daily use of marijuana concentrates.

RESULTS

Almost 60% of respondents were male, 86% were white, and the mean age was 43.0 years. About 48% reported marijuana concentrate use. After adjusting for multiple testing, significant predictors of concentrate use included: living in "recreational" (AOR = 2.04; adj. p = .042) or "medical, less restrictive" (AOR = 1.74; adj. p = .030) states, being younger (AOR = 0.97, adj. p = .008), and daily herbal cannabis use (AOR = 2.57, adj. p = .008). Out of 329 marijuana concentrate users, about 13% (n = 44) reported daily/near daily use. Significant predictors of daily concentrate use included: living in recreational states (AOR = 3.59, adj. p = .020) and using concentrates for therapeutic purposes (AOR = 4.34, adj. p = .020).

CONCLUSIONS

Living in states with more liberal marijuana policies is associated with greater likelihood of marijuana concentrate use and with more frequent use. Characteristics of daily users, in particular, patterns of therapeutic use warrant further research with community-recruited samples.

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Dynamic transitions between marijuana use and cigarette smoking among US adolescents and emerging adults

BACKGROUND

Marijuana and tobacco are considered two closely related substances. It is of great significance to understand the mutual impact of marijuana and cigarette use when more states in the US have legalized marijuana use.

OBJECTIVE

This study aims to investigate the transitions between marijuana and cigarette use among adolescents and emerging adults.

METHOD

Guided by the probabilistic discrete events systems (PDES) theory, a five-stage model with 21 transition paths was constructed to quantify dynamic transitions between marijuana and cigarette use. The five stages were NU: Never-user, MU: Current marijuana user, CU: Current cigarette user, MCU: Current marijuana-cigarette user, and FU: Former-user. The proposed five-stage PDES model was tested using the 2013 National Survey on Drug Use and Health data (N = 26,665, 50.45% male). Transition probabilities were estimated using the Moore-Penrose generalized inverse matrix method.

RESULT

Among the adolescents, 51.14% of the CUs transited to use marijuana (MCU/MU), higher than the proportion of those who first used marijuana and then transferred to cigarettes (MCU/CU) (41.66%). The quitting rates for MUs, CUs and MCUs were 29.38%, 25.93% and 27.76%, respectively. Of the total FUs, 31.90% transited to MUs, 17.06% to CUs, and 17.39% to MCUs. Among the young adults, more people progressed from MUs to CUs. Transition probabilities by single year of age were also estimated.

CONCLUSION

This is the first study to quantify marijuana-cigarette transitions. Study findings indicate more cigarette-to-marijuana transitions for adolescents and more marijuana-to-cigarette transitions for emerging adults. Future intervention programs should consider this age-related difference in marijuana-cigarette use transitions.

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.