Functional consequences of marijuana use in adolescents

Longitudinal examination of marijuana use and physical teen dating violence: Antisocial peers and impulsivity as mediators

BACKGROUND

Prior studies have shown that marijuana use is often associated with physical teen dating violence. However, few studies have examined the longitudinal mediating effects of associating with antisocial peers and impulsivity on this relationship. Also, few studies have estimated the cascading developmental impact of marijuana use and antisocial peer association, predicting the continued marijuana use and antisocial peer associations while considering the risk of impulsivity in physical teen dating violence. Thus, the current study utilized the problem behavior theory and an alternative path to physical dating violence to address these limitations.

OBJECTIVE

The current study tested the longitudinal effects of marijuana use on physical teen dating violence and the indirect effects of antisocial peer association and impulsivity on this relationship (M = 12.29); 52.1 % of males and 47.9 % of females participated.

METHODS

Adolescents completed questionnaires at baseline and were assessed six months later (n = 836). Generalized structural equation modeling (GSEM) and cross-lagged mediation models were used first to analyze the direct effect of lifetime marijuana use on physical dating violence and antisocial peer association and impulsivity as potential mediators of this relationship. Then, the cross-lagged mediation models were used to estimate the alternative path to physical teen dating violence using lifetime marijuana use and antisocial peer association as predictors at baseline and continued antisocial peer association, marijuana use, and impulsivity at the subsequent wave as mediators.

RESULTS

Results suggested that marijuana use at baseline was not positively associated with physical teen dating violence over time. The association with antisocial peers but not impulsivity mediated the relationship between marijuana use and physical dating violence. Cross-lagged mediation results suggested that marijuana use at baseline positively predicted antisocial peer association in the subsequent wave, which led to an increase in physical teen dating violence. Further, antisocial peer association at baseline is positively associated with continued antisocial peer association at the subsequent wave; thus, antisocial peer association is positively related to physical teen dating violence when controlling for depressive symptoms, family support, number of dates, and parental monitoring.

CONCLUSION

These results suggest though marijuana use alone is not statistically associated with physical teen dating violence, it does increase the risk of antisocial social peer associations that could increase adolescents' likelihood to engage in physical teen dating violence. Further, the onset of antisocial peer association could persist over time, thus serving as a risk factor for physical teen dating violence over time.

Sleep, Alcohol and Cannabis Use in College Students With and Without Attention-Deficit/Hyperactivity Disorder

Background: Relations among attention-deficit/hyperactivity disorder (ADHD), sleep, and substance-related negative consequences are largely unknown. In this cross-sectional study, we examined associations among ADHD diagnosis, sleep, and alcohol-related consequences. We also evaluated the independent and interactive effects of sleep and ADHD on alcohol-related negative consequences, above and beyond levels of alcohol use. Methods: College students who drink alcohol with (n = 51) and without (n = 50) ADHD completed an assessment that included a diagnostic interview assessing ADHD, and questionnaire measures of sleep quality, substance use, and associated consequences. Analyses utilized a series of hierarchical linear regression models and explored these aims for cannabis use in a subset of participants (n = 52 participants that used cannabis). Results: College students who drink alcohol with ADHD reported significantly worse sleep quality and more alcohol-related consequences, relative to those without ADHD. When ADHD and sleep quality were included in the model, ADHD-but not sleep quality-was independently associated with alcohol consequences, but not cannabis consequences. There were no moderating effects of ADHD on the associations between sleep and substance-related consequences. Conclusions: Students who drank alcohol with ADHD may be particularly vulnerable to experiencing poor sleep and consequences from their substance use, compared to their heavy drinking peers without ADHD. Future, larger scale studies should consider longitudinal effects as well as underlying mechanisms of risk.

Contingency management is associated with positive changes in attitudes and reductions in cannabis use even after discontinuation of incentives among non-treatment seeking youth

BACKGROUND

It is important to identify interventions that reduce harm in youth not motivated to change their cannabis use. This study evaluated how short-duration contingency management (CM) impacts cannabis use attitudes and behavior after abstinence incentives are discontinued among non-treatment seeking youth.

METHODS

Participants (N=220) were randomized to 4 weeks of abstinence-based CM (CB-Abst; n=126) or monitoring (CB-Mon; n=94). Participants completed self-report and provided biochemical measures of cannabis exposure at baseline, end-of-intervention, and 4-week follow-up. Changes in self-reported cannabis use frequency (days/week; times/week) and biochemically verified creatinine-adjusted 11-nor-9-carboxy-tetrahydrocannabinol concentrations (CN-THCCOOH) were analyzed between groups from baseline to follow-up. In CB-Abst, cannabis use goals at end-of-intervention were described and changes in cannabis use at follow-up were explored by goals and cannabis use disorder (CUD) diagnosis.

RESULTS

There was a group by visit interaction on cannabis use (days: beta=0.93, p=0.005; times: beta=0.71, p<0.001; CN-THCCOOH: beta=0.26, p=0.004), with reductions at follow-up detected only in CB-Abst. Following 4 weeks of abstinence, 68.4% of CB-Abst participants wanted to reduce or abstain from cannabis use following completion of CM. Those in CB-Abst who set end-of-intervention reduction goals and were without CUD had greater decreases in cannabis use frequency at follow-up (Goals*time on days/week: beta=-2.27, p<0.001; CUD*time on times/week: beta=0.48, SE=0.24, t=2.01, p=0.048).

CONCLUSIONS

Findings support the utility of brief incentivized abstinence for generating motivation to reduce cannabis use and behavior change even after incentives end. This study supports CM as a potentially viable harm reduction strategy for those not yet ready to quit.

What Substances Are Adolescents Vaping? Estimating Nicotine-Specific and Cannabis-Specific Vaping from US National Youth Surveys

BACKGROUND

Youth use of electronic cigarettes ("e-cigarettes") is an ongoing concern. Vaping is usually assumed to be of nicotine, but survey responses may also include vaping of non-nicotine substances (particularly cannabis), which can impose different risks. The current study quantifies the proportions of nicotine-specific and cannabis-specific vaping among adolescents.

METHODS

Data from the Monitoring the Future (MTF) 2021 survey were analyzed with respect to the substance vaped: nicotine, cannabis, or flavoring only. Past-30-day (P30D) nicotine-specific vaping (exclusively, or also having vaped other substances) and cannabis-specific vaping were calculated. Results were also broken down by grade level, cigarette smoking history (current, former, or never), and frequency of e-cigarette use (<20 vs. 20+ days in P30D).

RESULTS

Among 4706 P30D e-cigarette users, 84.2% vaped nicotine; the remaining 15.8% reported not vaping any nicotine in P30D. Cannabis vaping was reported by 48.4% of P30D vapers. Vaping both nicotine and cannabis in P30D was more common in current and former smokers than in never-smokers, and in frequent vapers (of any substance). Conversely, never-smokers were more commonly vaping cannabis but not nicotine, compared to current and former smokers. Supplementary NYTS 2022 analyses were consistent with these findings.

CONCLUSIONS

A notable proportion of self-reported P30D vapers reported not vaping nicotine; nearly half vaped cannabis. Capturing the variety of substances used in vaping devices is imperative for accurate public health surveillance of both nicotine and cannabis vaping among US adolescents, considering their different respective harms and regulatory frameworks.

Gone with the weed: incidents of adolescent marijuana use in the United States, 1976-2021

PURPOSE

This study sought to examine grouped and right-censored (GRC) counts of adolescent marijuana use and estimate its temporal trajectories and sociodemographic disparities over almost half a century.

METHODS

After compiling 46 waves of nationally representative data from the Monitoring the Future (MTF) study from 1976 to 2021 (sample size = 491,348), we utilized an innovative modified Poisson (mixture) approach to analyze past-year marijuana use quantified by GRC counts.

RESULTS

The overall reduction in incidence rates of marijuana use was attributable to an almost 40% reduction in the risk of marijuana use (with the proportion of at-risk adolescents at 51.36% in 1979 and 31.53% in 2021). Despite substantial changes over the study period, the recent incidence rates for at-risk individuals were similar to those in the early 1980s. Living in an intact family was a protective factor against adolescent marijuana use over time.

CONCLUSIONS

The incidence rates of marijuana use among at-risk students, especially those from disadvantaged families, remained high over the study period. The modified Poisson (mixture) approach serves as the preferred tool for modeling GRC responses. It is essential to distinguish among risk, at-risk incidence, and overall incidence when assessing substance use and other risky behaviors.

Change in marijuana use from adolescence to young adulthood and its relation to gestational alcohol and marijuana exposure

INTRODUCTION

Many studies have examined changes in marijuana use across adolescence, but few have examined factors associated with transitions from adolescence to young adulthood. We examined prenatal exposures to alcohol and marijuana and adolescent risk and protective factors that best distinguished among abstinence, continuity, or cessation of marijuana use from 16 to 22 years.

METHOD

Data were from the Maternal Health Practices and Child Development Project at the prenatal and 16- and 22-year follow-up phases. The offspring were of lower socioeconomic status with an average of 12.8 years of education at 22 years. Participants' frequency and quantity of marijuana use over the past year were used to determine change in use. A discriminant analysis was applied to distinguish among the identified groups. The risk factors considered included prenatal substance exposures and age 16 demographics, behavior, and home environment.

RESULT

Four categories of transitions were defined based on marijuana use from 16 to 22 years: non-users (n = 193), stop/decrease (n = 81), continue at same level/increase (n = 125), and initiation after the 16-year phase (n = 122). The factors that best distinguished among these groups were peers' marijuana use, delinquency, caregivers' financial strain, prenatal exposure to alcohol and marijuana, and race.

CONCLUSION

Prenatal alcohol and marijuana exposure were significantly related to transitions of marijuana use from adolescence to young adulthood, controlling for peers' use, behavior problems, and home environment. While gestational marijuana exposure was associated with early initiation/increasing use, alcohol exposure was related to later initiation. The findings emphasize the long-term effects of prenatal exposure to alcohol and marijuana.

Why get high? Coping and enjoyment motives mediate elevated cannabis demand and cannabis-related outcomes

OBJECTIVE

Cannabis is the most used psychoactive substance among adolescents and is a public health concern. Cannabis demand is a quantifiable measure of the reinforcing value of cannabis and comprises two latent-factors-amplitude (maximum consumption) and persistence (sensitivity to increasing costs). Cannabis demand and cannabis motives are important predictors of adolescent cannabis use and associated problems; however, little is known about how these two facets of motivation are causally related. Cannabis motives are thought to represent the final common pathway to cannabis use and may explain why elevated demand is associated with use and consequences. The present study tested whether internal cannabis motives (coping and enjoyment) mediated longitudinal associations between cannabis demand, use (hours high), and negative consequences.

METHOD

Participants aged 15-18 years old (n = 89, Mage = 17.0, SD = 0.9) who reported lifetime cannabis use completed online assessments of cannabis demand, motives, use and negative consequences at baseline, 3-month, and 6-month follow-up.

RESULTS

PROCESS mediation models revealed that enjoyment motives mediated the association between amplitude and persistence and use. In addition, coping motives mediated the association between amplitude and negative consequences.

CONCLUSIONS

These findings suggest that internal motives, while differentially related to aspects of demand and cannabis outcomes, are important in understanding adolescent cannabis use. Prevention efforts aimed at limiting access to cannabis and increasing access to substance-free activities may be important targets for adolescents. Further, cannabis interventions targeting specific motives for using (e.g., to cope with negative affect) may be important for reducing cannabis demand. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Prevalence of sleep disturbance among adolescents with substance use: a systematic review and meta-analysis

PURPOSE

Sleep disturbance has become a major challenge among adolescents worldwide. Substance use is among the most common factors contributing to sleep disturbance. This systematic review and meta-analysis examined the prevalence and categories of sleep disturbance among adolescents with substance use.

METHODS

We comprehensively searched for relevant studies published in the following databases from inception to August 2022: CINHAL (via EBSCOhost), PubMed, Scopus, Ovid Medline, Embase, ProQuest, and Web of Science. Data analysis was performed using Comprehensive Meta-Analysis version 3 software. We used a random-effects model to pool prevalence rates with 95% confidence intervals (CIs). Forest plots and p values for the Cochran Q statistic were used to evaluate heterogeneity among studies. Subgroup and meta-regression analyses were performed to compare the groups and identify the sources of heterogeneity.

RESULTS

We examined 18 studies that reported insomnia, hypersomnolence, sleep-related breathing disorders as sleep disturbances among adolescents with the use of alcohol, smoking, marijuana, and coffee. The total sample was 124,554. The overall prevalence rate of sleep disturbance was 29% (95% CI: 0.201-0.403). Subgroup analysis revealed that the prevalence rates of insomnia and hypersomnolence were higher among alcohol users (31%; 95% CI: 0.100-0.654) and smokers (46%; 95% CI: 0.232-0.700). The study design and method of assessment groups were the significant moderators that showed the source of variation in the included studies.

CONCLUSION

Sleep disturbance is highly prevalent among adolescents with substance use. Insomnia and hypersomnolence are more prevalent among alcohol users and smokers, respectively. On the basis of our findings, health-care providers can develop effective targeted interventions to reduce substance use, prevent sleep disturbance, and promote healthy sleep habits among adolescents.

Challenges and considerations for treating PTSD with medicinal cannabis: the Australian clinician's perspective

INTRODUCTION

Preclinical and experimental research have provided promising evidence that medicinal cannabis may be efficacious in the treatment of posttraumatic stress disorder (PTSD). However, implementation of medicinal cannabis into routine clinical therapies may not be straightforward.

AREAS COVERED

In this review, we describe some of the clinical, practical, and safety challenges that must be addressed for cannabis-based treatment of PTSD to be feasible in a real-world setting. These issues are especially prevalent if medicinal cannabis is to be combined with trauma-focused psychotherapy.

EXPERT OPINION

Future consideration of the clinical and practical considerations of cannabis use in PTSD therapy will be essential to both the efficacy and safety of the treatment protocols that are being developed. These issues include dose timing and titration, potential for addiction, product formulation, windows of intervention, and route of administration. In particular, exposure therapy for PTSD involves recall of intense emotions, and the interaction between cannabis use and reliving of trauma memories must be explored in terms of patient safety and impact on therapeutic outcomes.

Depressive Symptoms, Cannabis Use, and Transition Readiness among College Students with and without Chronic Medical Conditions

Background: College students experience increased responsibility for healthcare transition. They are at increased risk for depressive symptoms and cannabis use (CU), potentially modifiable predictors of successful healthcare transition. This study investigated how depressive symptoms and CU related to transition readiness, and if CU moderated the association between depressive symptoms and transition readiness for college students. Methods: College students (N = 1,826, Mage=19.31, SD = 1.22) completed online measures of depressive symptoms, healthcare transition readiness, and past-year CU. Regression identified 1) the main effects of depressive symptoms and CU on transition readiness and 2) examined if CU moderated the relationship between depressive symptoms and transition readiness with chronic medical conditions (CMC) status as a covariate. Results: Higher depressive symptoms were correlated with past-year CU (r=.17, p<.001) and lower transition readiness (r=-0.16, p<.001). In the regression model, higher depressive symptoms were related to lower transition readiness (ß=-0.02, p<.001); CU was not related to transition readiness (ß=-0.10, p=.12). CU moderated the relationship between depressive symptoms and transition readiness (B=.01, p=.001). The negative relationship between depressive symptoms and transition readiness was stronger for those with no past-year CU (B=-0.02, p<.001) relative to those with a past-year CU (ß=-0.01, p<.001). Finally, having a CMC was related to CU and higher depressive symptoms and transition readiness. Conclusions: Findings highlighted that depressive symptoms may hinder transition readiness, supporting the need for screening and interventions among college students. The finding that the negative association between depressive symptoms and transition readiness was more pronounced among those with past-year CU was counterintuitive. Hypotheses and future directions are provided.

Can I see some ID? Examining validity of the marijuana purchase task among late adolescent cannabis users

Cannabis demand (i.e., reinforcing value) can be assessed using a marijuana purchase task (MPT; assesses hypothetical purchasing of cannabis at escalating prices) and has been related to use frequency, problems, and cannabis use disorder symptoms in adults. Cannabis demand has yet to be studied in adolescents, which can inform prevention and intervention efforts to reduce cannabis-related risks. The present study sought to validate the MPT with a sample of late adolescent lifetime cannabis users. Participants aged 15-18 years old (n = 115, Mage = 16.9, SD = 0.9) residing in a state with legalized cannabis use completed online assessments at baseline and 6-month follow-up. Convergent and divergent validity was examined, while principal component analysis was conducted to determine the factor structure and assess predictive validity. Three indices, Omax (i.e., maximum expenditure on cannabis), breakpoint (i.e., price suppressing consumption to zero), and alpha (i.e., degree to which consumption decreases with increasing price) were all significantly associated with cannabis use, consequences, craving, and expenditures and significantly differentiated low-risk users and high-risk users as measured by the Cannabis Use Disorders Identification Test-Revised (CUDIT-R). A two-factor solution reflecting amplitude (intensity, alpha, Omax) and persistence (breakpoint, Pmax) was observed. Both factors were associated with cannabis use and consequences in baseline regression models. At follow-up, persistence was associated with consequences; amplitude was not associated with either outcome. These findings provide initial evidence that the MPT is a valid measure for assessing cannabis demand among adolescents and can be used to understand mechanisms of adolescent cannabis use. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Effect of Cannabis on Memory Consolidation, Learning and Retrieval and Its Current Legal Status in India: A Review

Cannabis is one of the oldest crops grown, traditionally held religious attachments in various cultures for its medicinal use much before its introduction to Western medicine. Multiple preclinical and clinical investigations have explored the beneficial effects of cannabis in various neurocognitive and neurodegenerative diseases affecting the cognitive domains. Tetrahydrocannabinol (THC), the major psychoactive component, is responsible for cognition-related deficits, while cannabidiol (CBD), a non-psychoactive phytocannabinoid, has been shown to elicit neuroprotective activity. In the present integrative review, the authors focus on the effects of cannabis on the different cognitive domains, including learning, consolidation, and retrieval. The present study is the first attempt in which significant focus has been imparted on all three aspects of cognition, thus linking to its usage. Furthermore, the investigators have also depicted the current legal position of cannabis in India and the requirement for reforms.

A Scoping Review of Risk and Protective Factors for Negative Cannabis Use Consequences

Objective

Numerous reviews have examined risk and protective factors for alcohol-related negative consequences, but no equivalent review of risk and protective factors exists for cannabis-related negative consequences (CRNCs)-a gap filled by the present study. This scoping review examined survey-based research of risk and protective factors for CRNCs such as neglecting responsibilities, blacking out, or needing more cannabis.

Methods

Three databases (PubMed, PsycINFO, and Google Scholar) were searched for peer-reviewed manuscripts published between January 1, 1990, and December 31, 2021. A qualitative synthesis was performed using the matrix method and the results were organized using the socioecological model as a framework.

Results

Eighty-three studies were included in the review. There was considerable variation in measures and operationalizations of CRNCs across studies. Risk factors were identified in the intrapersonal (depression, social anxiety, PTSD, impulsivity, sensation seeking, motives, expectancies), interpersonal/community (trauma, victimization, family and peer substance use, social norms), and social/policy (education, employment, community attachment, legalization, availability of substances) domains of influence. Protective behavioral strategies were a robust protective factor for CRNCs. Males consistently reported more CRNCs than females, but there were no differences observed across race.

Conclusions

Future research should identify person- and product-specific patterns of CRNCs to refine theoretical models of cannabis misuse and addiction. Public health interventions to reduce the risk of negative consequences from cannabis should consider utilizing multilevel interventions to attenuate the cumulative risk from a combination of psychological, contextual, and social influences.

Risk factors for alcohol use among adolescents: The context of township high schools in Tshwane, South Africa

Background

Risk factors for alcohol use originate from many interconnected factors to an interplay of social and physical environments. However, there is a scarcity of data on the contextual risk factors of alcohol use among the adolescents regarding high schools located in townships in South Africa. This study aimed to determine the risk factors for alcohol use among adolescents attending selected township high schools in Tshwane, South Africa.

Method

A validated researcher-administered questionnaire was used to collect data on the demographics, as well as current alcohol use, types, quantity, and frequency among adolescents (n = 403) in the three high schools. Data were analyzed using STATA 17.

Results

The response rate was 97%, with the mean age of 16 ± 2 years for the adolescents. Forty-eight % (48%) of the adolescents reported current alcohol use, which was associated with sex, age, number of children, school grade, repeated grade, spare time job and types, having a pocket money to school, child social grant, transport mode to school, and smoking. The odds of current alcohol use were higher for adolescents in grade 10 [AOR = 6.71; 95% CI: 3.16-14.24], grade 11 [AOR = 4.45; 95% CI: 2.21], grade 12 [AOR = 3.05; 95% CI: 1.47-6.31], repeating a grade [AOR =2 .20; 95% CI: 1.32-3.67), and working during a spare time [AOR = 2.91; 95% CI: 1.33-6.37]. Both sexes had higher odds of alcohol use in the ages of 15-17 and 18-21 years, than adolescents aged 13-14 years.

Conclusion

Key risk factors for alcohol use among learners were sex, age, school grade, repeated grade, and working during a spare time. More evidence-based interventions that would have a greater impact in addressing alcohol use among adolescents, such as focusing on availability, marketing, and taxation of alcoholic beverages, are necessary.

Adolescent self-administration of the synthetic cannabinoid receptor agonist JWH-018 induces neurobiological and behavioral alterations in adult male mice

RATIONALE

The use of synthetic cannabinoid receptor agonists (SCRAs) is growing among adolescents, posing major medical and psychiatric risks. JWH-018 represents the reference compound of SCRA-containing products.

OBJECTIVES

This study was performed to evaluate the enduring consequences of adolescent voluntary consumption of JWH-018.

METHODS

The reinforcing properties of JWH-018 were characterized in male CD1 adolescent mice by intravenous self-administration (IVSA). Afterwards, behavioral, neurochemical, and molecular evaluations were performed at adulthood.

RESULTS

Adolescent mice acquired operant behavior (lever pressing, Fixed Ratio 1-3; 7.5 µg/kg/inf); this behavior was specifically directed at obtaining JWH-018 since it increased under Progressive Ratio schedule of reinforcement, and was absent in vehicle mice. JWH-018 IVSA was reduced by pretreatment of the CB1-antagonist/inverse agonist AM251. Adolescent exposure to JWH-018 by IVSA increased, at adulthood, both nestlet shredding and marble burying phenotypes, suggesting long-lasting repetitive/compulsive-like behavioral effects. JWH-018 did not affect risk proclivity in the wire-beam bridge task. In adult brains, there was an increase of ionized calcium binding adaptor molecule 1 (IBA-1) positive cells in the caudate-putamen (CPu) and nucleus accumbens (NAc), along with a decrease of glial fibrillary acidic protein (GFAP) immunoreactivity in the CPu. These glial alterations in adult brains were coupled with an increase of the chemokine RANTES and a decrease of the cytokines IL2 and IL13 in the cortex, and an increase of the chemokine MPC1 in the striatum.

CONCLUSIONS

This study suggests for the first time that male mice self-administer the prototypical SCRA JWH-018 during adolescence. The adolescent voluntary consumption of JWH-018 leads to long-lasting behavioral and neurochemical aberrations along with glia-mediated inflammatory responses in adult brains.

Assessment of Withdrawal, Mood, and Sleep Inventories After Monitored 3-Week Abstinence in Cannabis-Using Adolescents and Young Adults

Introduction: Among adolescents and young adults, cannabis use is prevalent. Prior studies characterizing withdrawal effects in this age range have primarily included treatment seeking or comorbid psychiatric samples; these studies have identified several affected domains, especially sleep, mood, and anxiety. The present study compared a community (i.e., nontreatment seeking) sample of cannabis-using and control participants on mood, anxiety, sleep, and withdrawal inventories during the course of a monitored 3-week cannabis abstinence period. Materials and Methods: Seventy-nine adolescent and young adult participants (cannabis-using group=37 and control group=42) were recruited from the community to undergo 3 weeks of confirmed abstinence (i.e., urine and sweat patch toxicology) and completion of Cannabis Withdrawal Symptom Criteria, State-Trait Anxiety Inventory, Beck's Depression Inventory, and Pittsburgh Sleep Quality Index across the study period. Repeated measures and cross-sectional regressions were used to examine main effects of group and interactions with time (where appropriate), while accounting for recent alcohol use and cotinine levels. Results: Cannabis-using participants reported higher mood (p=0.006), overall withdrawal (p=0.009), and sleep-related withdrawal (p<0.001) symptoms across abstinence compared to controls. Overall withdrawal severity (p=0.04) and sleep-related withdrawal symptoms (p=0.02) demonstrated a quadratic trajectory across the monitored abstinence periods, with an increase from baseline and subsequent decreases in symptom severity. No differences of anxiety scores (p=0.07) or trajectories (p=0.18) were observed. By study completion, groups did not differ among sleep quality components (all p's>.05). Conclusions: These findings revealed that nontreatment-seeking cannabis-using adolescents and young adults reported heightened total withdrawal symptoms during a 3-week sustained abstinence period relative to controls. Cannabis-using participants demonstrated an increase in withdrawal symptom trajectory during the first week followed by decreased symptoms from weeks 2 to 3, which contrasts with prior linear decreases observed in cannabis-using adolescent and young adults. More mood symptoms were observed in the cannabis-using group even while excluding for comorbid psychopathologies-along with significantly more sleep problems during the abstinence period. Implications include the necessity to provide psychoeducation for recreational, nontreatment-seeking cannabis-using individuals about cannabis withdrawal, mood symptoms, and sleep quality difficulties when cannabis cessation is attempted, to improve likelihood of long-term sustained abstinence.

A Meta-Analysis of fMRI Studies of Youth Cannabis Use: Alterations in Executive Control, Social Cognition/Emotion Processing, and Reward Processing in Cannabis Using Youth

Background: Adolescent cannabis use (CU) is associated with adverse health outcomes and may be increasing in response to changing cannabis laws. Recent imaging studies have identified differences in brain activity between adult CU and controls that are more prominent in early onset users. Whether these differences are present in adolescent CU and relate to age/developmental stage, sex, or cannabis exposure is unknown. Methods: A systematic review and subsequent effect-size seed-based d mapping (SDM) meta-analysis were conducted to examine differences in blood-oxygen-level-dependent (BOLD) response during fMRI studies between CU and non-using typically developing (TD) youth. Supplemental analyses investigated differences in BOLD signal in CU and TD youth as a function of sex, psychiatric comorbidity, and the dose and severity of cannabis exposure. Results: From 1371 citations, 45 fMRI studies were identified for inclusion in the SDM meta-analysis. These studies compared BOLD response contrasts in 1216 CU and 1486 non-using TD participants. In primary meta-analyses stratified by cognitive paradigms, CU (compared to TD) youth showed greater activation in the rostral medial prefrontal cortex (rmPFC) and decreased activation in the dorsal mPFC (dmPFC) and dorsal anterior cingulate cortex (dACC) during executive control and social cognition/emotion processing, respectively. In meta-regression analyses and subgroup meta-analyses, sex, cannabis use disorder (CUD) severity, and psychiatric comorbidity were correlated with brain activation differences between CU and TD youth in mPFC and insular cortical regions. Activation differences in the caudate, thalamus, insula, dmPFC/dACC, and precentral and postcentral gyri varied as a function of the length of abstinence. Conclusions: Using an SDM meta-analytic approach, this report identified differences in neuronal response between CU and TD youth during executive control, emotion processing, and reward processing in cortical and subcortical brain regions that varied as a function of sex, CUD severity, psychiatric comorbidity, and length of abstinence. Whether aberrant brain function in CU youth is attributable to common predispositional factors, cannabis-induced neuroadaptive changes, or both warrants further investigation.

Using machine learning to determine the shared and unique risk factors for marijuana use among child-welfare versus community adolescents

OBJECTIVE

This study used machine learning (ML) to test an empirically derived set of risk factors for marijuana use. Models were built separately for child welfare (CW) and non-CW adolescents in order to compare the variables selected as important features/risk factors.

METHOD

Data were from a Time 4 (Mage = 18.22) of longitudinal study of the effects of maltreatment on adolescent development (n = 350; CW = 222; non-CW = 128; 56%male). Marijuana use in the past 12 months (none versus any) was obtained from a single item self-report. Risk factors entered into the model included mental health, parent/family social support, peer risk behavior, self-reported risk behavior, self-esteem, and self-reported adversities (e.g., abuse, neglect, witnessing family violence or community violence).

RESULTS

The ML approaches indicated 80% accuracy in predicting marijuana use in the CW group and 85% accuracy in the non-CW group. In addition, the top features differed for the CW and non-CW groups with peer marijuana use emerging as the most important risk factor for CW youth, whereas externalizing behavior was the most important for the non-CW group. The most important common risk factor between group was gender, with males having higher risk.

CONCLUSIONS

This is the first study to examine the shared and unique risk factors for marijuana use for CW and non-CW youth using a machine learning approach. The results support our assertion that there may be similar risk factors for both groups, but there are also risks unique to each population. Therefore, risk factors derived from normative populations may not have the same importance when used for CW youth. These differences should be considered in clinical practice when assessing risk for substance use among adolescents.

Longitudinal associations between e-cigarette use and onset of multiple modes of cannabis use among US adolescents

OBJECTIVE

To examine the prospective associations between e-cigarette use and subsequent onset of various modes of cannabis use during a 12-month follow-up period among US adolescents.

METHODS

Data were from the Wave 4 (2017, baseline) and Wave 4.5 (12-month follow-up) surveys of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal cohort study. Study population was cannabis-naïve US adolescents (12-16 years) at baseline who reported cannabis use status at follow-up (N = 9,692). Outcomes were modality-specific past-12-month cannabis use (vaping, blunting, smoking with hookah) and any cannabis use (past-12-month and past-30-day) at follow-up. Multivariate logistic regressions were used to estimate the weighted association between baseline past-30-day e-cigarette use and each outcome.

RESULTS

Baseline e-cigarette use was significantly associated with onset of cannabis vaping (aOR = 4.00, 95% CI = 2.25-7.10), blunting (aOR = 5.30, 95% CI = 2.82-9.94), any cannabis use (aOR = 3.94, 95% CI = 2.35-6.62), and past-30-day cannabis use (aOR = 4.47, 95%CI = 2.64-7.58) at follow-up. Non-Hispanic blacks were more likely to report past-12-month blunting (aOR = 1.55, 95% CI = 1.07-2.24) and smoking cannabis with hookah (aOR = 3.13, 95% CI = 1.14-8.63) compared with non-Hispanic whites. Other tobacco use, alcohol use, perceiving e-cigarette use as having little or some harm, older age, high severity of externalizing mental health problems, and living in states legalized adult recreational cannabis use were significantly associated with future onset of cannabis vaping, blunting, and any cannabis use.

CONCLUSIONS

The association of e-cigarette use with cannabis vaping was not stronger than its association with other modes of cannabis use. Future studies are needed to explain the mechanisms linking e-cigarettes and cannabis use.

Effects of cannabinoid exposure on short-term memory and medial orbitofrontal cortex function and chemistry in adolescent female rhesus macaques

Aim

There is increasing concern that cannabinoid exposure during adolescence may disturb brain maturation and produce long-term cognitive deficits. However, studies in human subjects have provided limited evidence for such causality. The present study utilized behavioral and neuroimaging endpoints in female non-human primates to examine the effects of acute and chronic exposure during adolescence to the cannabinoid receptor full agonist, AM2389, on cognitive processing and brain function and chemistry.

Materials and methods

Adolescent female rhesus macaques were trained on a titrating-delay matching-to-sample (TDMTS) touchscreen task that assays working memory. TDMTS performance was assessed before and during chronic exposure to AM2389, following antagonist (rimonabant) administration, and after discontinuation of the chronic regimen. Resting-state fMRI connectivity and magnetic resonance spectroscopy data were acquired prior to drug treatment, during chronic exposure, and following its discontinuation. Voxels were placed in the medial orbitofrontal cortex (mOFC), a region involved in memory processing that undergoes maturation during adolescence.

Results

TDMTS performance was dose-dependently disrupted by acute AM2389; however, chronic treatment resulted in tolerance to these effects. TDMTS performance also was disrupted by discontinuation of the chronic regimen but surprisingly, not by rimonabant administration during chronic AM2389 treatment. mOFC N-acetylaspartate/creatine ratio decreased after acute and chronic administration but returned to baseline values following discontinuation of chronic treatment. Finally, intra-network functional connectivity (mOFC) increased during the chronic regimen and returned to baseline values following its discontinuation.

Conclusion

Neural effects of a cannabinergic drug may persist during chronic exposure, notwithstanding the development of tolerance to behavioral effects. However, such effects dissipate upon discontinuation, reflecting the restorative capacity of affected brain processes.

The impact of cannabis legalization for recreational purposes on youth: A narrative review of the Canadian experience

Cannabis legalization for non-medical purposes (subsequently referred to as "cannabis legalization" or "legalization") took place in Canada in October 2018. One of the federal government's stated goals with cannabis legalization was to protect Canadian youth from cannabis-related harms. The main objective of this narrative review is to describe the impact of cannabis legalization on Canadian youth. To that end, we discuss the regulation of the Canadian cannabis market, outline changes in the epidemiology and parameters of cannabis use (modes of use, potency of cannabis) among youth, and discuss prevention and education initiatives related to cannabis. The Canadian model differs from other jurisdictions that legalized recreational cannabis use, especially with regard to a higher degree of government regulation of the cannabis market. Another difference is the development and endorsement of lower-risk cannabis use guidelines to educate the public and health professionals. The results available for this review cover only 3 years post-legalization. Cannabis legalization in Canada brought an apparent increase in use among Canadian older than 25. However, results for youth are mixed, with the majority of studies showing no pronounced increase. Notably, the trend of a decrease in adolescents' cannabis use seen pre-legalization may have reversed. Emerging evidence also suggests that cannabis-related hospitalizations and emergency department visits among Canadian youth may have increased due to cannabis legalization. Data about changes in the age of initiation, the influence of legalization on sex and gender, and race/ethnicity are limited, with evidence suggesting that the age of initiation slightly increased. So far, there is limited data about the impact of cannabis legalization on Canadian youth. Further long-term monitoring and research to assess the effects of cannabis legalization on Canadian youth.

The different role of G-protein-coupled receptor 30 (GPR30) in the interaction effects of marijuana and estradiol on spatial learning and memory at different ages

Some studies suggest that the effect of cannabis on behavior performance depends on the presence of ovarian hormones and the age of use initiation. Estradiol is the main ovarian hormone that can interact with cannabinoids. It has been suggested that cannabinoids exert some of their effects directly through estrogen receptors (ERs). A novel G-protein-coupled receptor (GPR30) was described as mediating estrogen signaling in various cell lines. Since there are few studies on the interaction of cannabis and ovarian hormones on cognitive behaviors, so, this study evaluated the role of GPR30 in the effects of marijuana (M) and estrogen, alone and in combination, on spatial learning and memory of young (non-ovarian(OVX)) and old female rats. Young (5-7 months) and old (22-24 months) female rats received an intraperitoneal injection (i.p) of 17β-estradiol (E2), G1 (GPR30 agonist), and G15 (GPR30 antagonist) every four days, and M (every day), either alone or in combination, for 28 days. One hour after the last injection, the Morris water maze (MWM) test was conducted to evaluate of spatial learning and memory. Moreover, hippocampal BDNF level was assessed by the ELISA method. The results showed a positive effect of M on spatial learning in both young and old rats, however, E2 showed beneficial effects on the memory of young, but not old rats. Our results showed that GPR30 does not have any role in the interaction effects of M and E2 in young rats. Although both E2 and M alone showed positive effects on spatial learning and memory in old rats, however, our results showed a negative interaction between marijuana and E2 combined effects on spatial learning and memory in old female rats which is mediated by GPR30. Our results showed that the effects of GPR30 on spatial learning and memory is age dependent. Furthermore, this study showed that hippocampal BDNF does not have any role in the interaction effects of M and E2 on spatial learning and memory in young and old rats.

Perceived risk of harm from monthly cannabis use among US adolescents: National Survey on drug Use and Health, 2017

There has been a steady increase in cannabis use among US adolescents over the past decade. Perceptions of risk, specifically the belief that cannabis use is not harmful, may contribute to this increased use. The purpose of this study was to evaluate parental, school, and peer influence as protective factors in perceiving there is risk of harm from monthly cannabis use. Using the 2017 National Survey on Drug Use and Health (NSDUH), the study outcome was self-reported perceived risk of harm from monthly cannabis use amongst adolescents between ages 12 and 17. The exposures were parental monitoring and support, perception of school importance, extracurricular activity participation, peer attitudes towards cannabis use, and perception of peer cannabis use. Of 12,024 eligible adolescents, about 80% reported perceived risk of harm from monthly cannabis use. Multiple logistic regression models suggest the perception of risk of harm from monthly cannabis use was significantly associated with perception of peers using cannabis, perception of peers' disapproval of cannabis use, perception of school importance, and participation in extracurricular activities. Adolescents who perceived that monthly cannabis use was risky had high parental monitoring, low perception of peer use, high perception of peers' disapproval of cannabis use, high perception of school importance, and participated more in extracurricular activities. These findings suggest substance use prevention programs targeting adolescent attitudes and beliefs would benefit from leveraging peer influence, promoting extracurricular activities, and enhancing schoolwork to be more meaningful.

Down and High: Reflections Regarding Depression and Cannabis

In light of the recent changes in the legal status of cannabis in Canada, the understanding of the potential impact of the use of cannabis by individuals suffering from depression is increasingly considered as being important. It is fundamental that we look into the existing literature to examine the influence of cannabis on psychiatric conditions, including mood disorders. In this article, we will explore the relationship that exists between depression and cannabis. We will examine the impact of cannabis on the onset and course of depression, and its treatment. We have undertaken a wide-ranging review of the literature in order to address these questions. The evidence from longitudinal studies suggest that there is a bidirectional relationship between cannabis use and depression, such that cannabis use increases the risk for depression and vice-versa. This risk is possibly higher in heavy users having initiated their consumption in early adolescence. Clinical evidence also suggests that cannabis use is associated with a worse prognosis in individuals with major depressive disorder. The link with suicide remains controversial. Moreover, there is insufficient data to determine the impact of cannabis use on cognition in individuals with major depression disorder. Preliminary evidence suggesting that the endogenous cannabinoid system is involved in the pathophysiology of depression. This will need to be confirmed in future positron emission tomography studies. Randomized controlled trials are needed to investigate the potential efficacy of motivational interviewing and/or cognitive behavioral therapy for the treatment of cannabis use disorder in individuals with major depressive major disorder. Finally, although there is preclinical evidence suggesting that cannabidiol has antidepressant properties, randomized controlled trials will need to properly investigate this possibility in humans.

The Influence of Cannabis and Nicotine Co-use on Neuromaturation: A Systematic Review of Adolescent and Young Adult Studies

Accumulating evidence suggests that the use of cannabis and nicotine and tobacco-related products (NTPs) during the adolescent years has harmful effects on the developing brain. Yet, few studies have focused on the developing brain as it relates to the co-administration of cannabis and NTPs, despite the high prevalence rates of co-use in adolescence. This review aims to synthesize the existing literature on neurocognitive, structural neuroimaging, and functional neuroimaging outcomes associated with cannabis and NTP co-use. A systematic search of peer-reviewed articles resulted in a pool of 1107 articles. Inclusion criteria were 1) data-based study; 2) age range of 13 to 35 years or, for preclinical studies, nonadult subjects; 3) cannabis and NTP group jointly considered; and 4) neurocognitive, structural neuroimaging, or functional neuroimaging as an outcome measure. Twelve studies met inclusion criteria. Consistent with the literature, cannabis and nicotine were found to have independent effects on cognition. The available research on the co-use of cannabis and NTPs demonstrates a potential nicotine-related masking effect on cognitive deficits associated with cannabis use, yet there is little research on co-use and associations with neuroimaging indices. In neuroimaging studies, there is preliminary evidence for hippocampal volume differences in co-users and a lack of evidence for co-use differences related to nucleus accumbens activity during reward processing. Notably, no structural neuroimaging studies were found to examine the combined effects of nicotine and cannabis in adolescent-only populations. Further research, including longitudinal studies, is warranted to investigate the influence of cannabis and NTP co-use on maturation.

Investigating the Residual Effects of Chronic Cannabis Use and Abstinence on Verbal and Visuospatial Learning

Rationale: Regular cannabis users have been shown to differ from non-using controls in learning performance. It is unclear if these differences are specific to distinct domains of learning (verbal, visuospatial), exacerbate with extent of cannabis exposure and dissipate with sustained abstinence. Objective: This study examines different domains of learning (verbal, visuospatial) in current and abstaining cannabis users, and the role of chronicity of use. Methods: In a cross-sectional design, we examined 127 psychiatrically healthy participants (65 female) with mean aged of 34 years. Of these, 69 individuals were current regular cannabis users (mean 15 years use), 12 were former cannabis users abstinent for ~2.5 yrs (after a mean of 16 years use), and 46 were non-cannabis using controls. Groups were compared on verbal learning performance assessed via the California Verbal Learning Test (CVLT-II) and for visuospatial learning measured with the Brown Location Test (BLT). We explored the association between CVLT/BLT performance and cannabis use levels in current and former users. Results: Current cannabis use compared to non-use was associated with worse performance on select aspects of verbal learning (Long Delay Cued Recall) and of visuospatial learning (Retroactive Interference and LD Rotated Recall). Prolonged abstinence was associated with altered verbal learning but intact visuospatial learning. There were non-significant correlations between distinct cannabis use measures, age and learning in both current and former users. Conclusions: Our findings suggest cannabis use status (current use, former use) affects different domains of learning (verbal and visuospatial) in a distinct fashion. These findings might be accounted for in the design of cognitive interventions aimed to support abstinence in cannabis users.

Factors Associated with Poly Drug Use in Adolescents

Poly drug use in adolescents represents a significant public health issue, heightening risk for abuse, dependency, and a variety of short- and long-term psychological, psychosocial, and health consequences. However, past studies have typically examined just one or two substances in isolation and there is a lack of research that has comprehensively examined possible predictors of poly drug use in adolescents. To inform the development of comprehensive prevention programs that can simultaneously target multiple substances, the present study sought to identify psychological, environmental, and demographic factors that are most strongly associated with alcohol, tobacco, and cannabis poly drug use. Adolescents aged 15 to 17 years (n = 1661; 50.9% male) completed a survey on their use of alcohol, tobacco, and cannabis over the last 30 days. Various psychological, environmental, and demographic factors were also assessed. Weighted multiple-level logistic regression was conducted to assess the factors associated with poly drug use. In total, 20.3% of respondents had used at least one substance, 6.7% reported using two substances, and 3.3% reported using all three substances. The most common combined pattern of use was alcohol and tobacco, followed by alcohol and cannabis. Several factors emerged as significant, with conduct problems, depression, and the school environment accounting for the most variance. Specific psychological and environmental factors appear to be particularly important domains to target in adolescent substance use prevention programs. Early identification of adolescent depression and conduct problems and the development of programs that address these symptoms in youth may be effective approaches to delaying or preventing poly drug use in this population.

Cannabis use among U.S. adolescents in the era of marijuana legalization: a review of changing use patterns, comorbidity, and health correlates

Decriminalization, medicalization, and legalization of cannabis use by a majority of U.S. states over the past 25 years have dramatically shifted societal perceptions and use patterns among Americans. How marijuana policy changes have affected population-wide health of U.S. youth and what the downstream public health implications of marijuana legalization are topics of significant debate. Cannabis remains the most commonly used federally illicit psychoactive drug by U.S. adolescents and is the main drug for which U.S. youth present for substance use treatment. Converging evidence indicates that adolescent-onset cannabis exposure is associated with short- and possibly long-term impairments in cognition, worse academic/vocational outcomes, and increased prevalence of psychotic, mood, and addictive disorders. Odds of negative developmental outcomes are increased in youth with early-onset, persistent, high frequency, and high-potency Δ-9-THC cannabis use, suggesting dose-dependent relationships. Cannabis use disorders are treatable conditions with clear childhood antecedents that respond to targeted prevention and early intervention strategies. This review indicates that marijuana policy changes have had mixed effects on U.S. adolescent health including potential benefits from decriminalization and negative health outcomes evidenced by increases in cannabis-related motor vehicle accidents, emergency department visits, and hospitalizations. Federal and state legislatures should apply a public health framework and consider the possible downstream effects of marijuana policy change on paediatric health.

Cannabis and the Developing Adolescent Brain

Purpose of Review

This review summarizes (1) recent trends in delta-9-tetrahydrocannabionol [THC] and cannabidiol (CBD) content in cannabis products, (2) neurobiological correlates of cannabis use on the developing adolescent brain, (3) effects of cannabis on psychiatric symptoms and daily functioning in youth (i.e., academic performance, cognition, sleep and driving), (4) cannabis products used to relieve or treat medical issues in youth, and (5) available treatments for cannabis use disorder in adolescence.

Recent findings

Despite marked increases in THC content and availability of cannabis, there has been a decline in perceived risk and an increase in use of THC extract products among youth in the United States. The primary psychiatric symptoms associated with cannabis use in youth are increased risk for addiction, depressive, and psychotic symptoms. Cannabis alters endocannabinoid system function which plays a central role in modulating the neurodevelopment of reward and stress systems. To date, few studies have examined neurobiological mechanisms underlying the psychiatric sequalae of cannabis exposure in youth. Adolescent cannabis exposure results in impaired cognition, sleep, and driving ability. There are very limited FDA-approved cannabinoid medications, none of them supporting their use for the treatment of psychiatric symptoms. Behavioral therapies are currently the mainstay of treating cannabis misuse, with no pharmacotherapies currently approved by the FDA for cannabis use disorder in youth.

Summary

Here, we summarize the most up-to-date knowledge on the neurobiological psychiatric, and daily function effects of the most commonly used cannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). We then review FDA approved medical use of cannabinoid treatments as well as pharmacological and psychological treatments for cannabis use disorder in youth. Our current understanding of the effects of cannabis on the developing brain and treatments for cannabis misuse in youth remain limited. Future research aimed at examining the neurobiological effects of cannabis, with objective measures of exposure, over the course of pediatric development and in relation to psychiatric symptoms are needed.

The Vaping Epidemic in Adolescents

Electronic cigarette (e-cigarette) use has recently risen to the forefront of medical discussions across the country. A significant increase in e-cigarette use by adolescents has been observed over the last decade. This article discusses the targeting of adolescents by e-cigarette companies. It looks at how teenagers are uniquely affected by nicotine and at risk for progressing to using combustible cigarettes and marijuana. Lastly, it discusses the role of physicians in combating the spread of e-cigarettes.

Is the Adolescent Brain at Greater Vulnerability to the Effects of Cannabis? A Narrative Review of the Evidence

Cannabis use during the critical neurodevelopmental period of adolescence, may lead to brain structural, functional, and histological alterations that may underpin some of the longer-term behavioral and psychological harms associated with it. The endocannabinoid system performs a key regulatory and homeostatic role, that undergoes developmental changes during adolescence making it potentially more susceptible to the effects of exposure to cannabis during adolescence. Here, we synthesize evidence from human studies of adolescent cannabis users showing alterations in cognitive performance as well as in brain structure and function with relevant preclinical evidence to summarize the current state of knowledge. We also focus on the limited evidence that speaks to the hypothesis that cannabis use during adolescence, may pose a greater risk than use during adulthood, identify gaps in current evidence and suggest directions for new research. Existing literature is consistent with the association of cannabis use during adolescence and neurological changes. Adolescence cannabis users show altered functional connectivity within known functional circuits, that may underlie inefficient recruitment of brain regions, as largely increased functional activation has been observed compared to controls. This disruption in some cases may contribute to the development of adverse mental health conditions; increasing the chances or accelerating the onset, of their development. Preclinical evidence, further supports disruption from cannabis use being specific to the developmental period. Future studies are required to better investigate adolescent cannabis use with more accuracy using better defined groups or longitudinal studies and examine the permanency of these changes following caseation of use. Furthermore, research is required to identify heritable risk factors to cannabis use. There is a need for caution when considering the therapeutic potential of cannabis for adolescence and particularly in public discourse leading to potential trivialization of possible harm from cannabis use in adolescence. Current evidence indicates that adolescence is a sensitive period during which cannabis use may result in adverse neurocognitive effects that appear to show a level of permanency into adulthood.

Beyond the Bud: Emerging Methods of Cannabis Consumption for Youth

Cannabis continues to be the most widely used illicit substance among youth, as many teens view the risks of cannabis consumption to be low. With cannabis laws becoming lax and dispensaries becoming more prevalent throughout the United States, highly concentrated Δ-9-tetrahydrocannibinol (THC) is becoming readily available. This article examines the available literature on consumption of concentrated THC, focusing on potential consequences of concentrate use among youth. Various methods for consuming concentrated THC, including ingestion of edibles, vaping, and dabbing, are discussed, along with associated risks of each consumption method. Recommendations for health professionals are provided.

Intergenerational marijuana use: A life course examination of the relationship between parental trajectories of marijuana use and the onset of marijuana use by offspring

Prior research documents intergenerational (IG) continuity in marijuana use, with most work adopting a life course perspective. Incorporating a methodology that allows for the measurement of "patterns of behavior" instead of singular aspects of parent marijuana use (e.g., age of onset or frequency at any one age or ages), we investigated the simultaneous effects of parental age of onset, frequency, and duration of marijuana use across 3 periods of the life course (i.e., adolescence, emerging adulthood, and adulthood) on the timing of first marijuana use among offspring. Using prospective data from 2 companion studies, the Rochester Youth Development Study and the Rochester Intergenerational Study, we used group-based trajectory models to estimate trajectories (or patterns) of parental marijuana use spanning ages 14 to 31 among a birth cohort of 462 parents. We then examined the relationship between parental trajectories of marijuana use and the timing of the onset of marijuana use through age 25 among firstborn offspring. Both late-onset persistent use by parents and increasing chronic use spanning adolescence to adulthood by parents were associated with an increased likelihood of onset of marijuana use among offspring. The results underscore the importance of patterns of marijuana use for IG continuity in contrast to singular measures (e.g., age of onset among parents), which can obfuscate important IG patterns of continuity. Prevention and intervention programs should consider the entire history of parent use to better identify children most at risk for the onset of marijuana use in adolescence and emerging adulthood. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Medical, therapeutic, and recreational use of cannabis among young men who have sex with men living with HIV

Cannabis plays a role in symptoms management in HIV, especially the alleviation of pain and nausea and stimulation of appetite, and prevalence of cannabis use in HIV-positive populations exceeds that of the general U.S. population. Previous research has described an "overlap" between medical and recreational cannabis use among persons living with HIV. To understand better the motives associated cannabis use among young men who have sex with men living with HIV (HIV+ YMSM), we conducted semi-structured interviews with 30 HIV+YMSM in Denver and Chicago. Interviews were audio-recorded, transcribed, and coded by a diverse team of analysts. In addition to findings that mapped onto previously identified medical motives and recreational motives, we identified several themes that straddled medical and recreational use in a domain we describe as therapeutic. Themes identified in this therapeutic domain of cannabis use include (a) enhanced introspection among individuals that promotes psychological adjustment to an HIV diagnosis, improved medical management, and future orientation; (b) reflection processes that mitigate interpersonal conflict and improve interpersonal communication; and (c) a social-therapeutic phenomena of cannabis use among young persons with living HIV that is characterized by both enhanced introspection and improved interpersonal communication. Our findings suggest a spectrum of cannabis use among HIV+ YMSM that may be characterized not only by an overlap between medical and recreational use, but also by a distinct therapeutic domain that incorporates stress alleviation and cognitive expansion processes to improve focus on HIV management and self-care.

Demographic, Cannabis Use, and Depressive Correlates of Cannabis Use Consequences in Regular Cannabis Users

BACKGROUND AND OBJECTIVES

Regular cannabis users experience cannabis-related consequences across many domains of functioning. The present study examined demographic, cannabis use, and depressive correlates of cannabis consequences. We hypothesized that (1) earlier onset of use would predict greater psychological and functional consequences; and (2) women would endorse more psychological and withdrawal consequences.

METHODS

Data were collected from an urban sample of 184 adults who reported regular cannabis use. Seventeen items from a cannabis consequence checklist were grouped into three domains: Psychological Consequences, Cannabis Withdrawal, and Functional Consequences. Three multiple regressions were performed to explore demographic and cannabis use correlates of each domain. Correlations between domains and depressive symptoms were assessed using Pearson's r.

RESULTS

Greater endorsement on the Psychological Consequence subgroup was predicted by female sex, lower educational attainment, and treatment-seeking history for cannabis abuse/dependence. Individuals with greater number of quit attempts or treatment-seeking history endorsed more items in the Cannabis Withdrawal domain. Although the model failed to reach significance for Functional Consequences, age at onset of regular and daily cannabis use were negatively associated with this domain. Correlational analyses demonstrated higher Beck Depression Inventory-Second Edition scores were related to greater endorsement of Psychological Consequence and Cannabis Withdrawal items.

DISCUSSION AND CONCLUSIONS

Regular cannabis users report consequences of use, which can be grouped into content-specific subgroups. Individual characteristics are differentially associated with these subgroups.

SCIENTIFIC SIGNIFICANCE

Understanding which individual characteristics are related to cannabis use sequelae could help identify those at risk for greater consequences, thus leading to improved assessment and treatment interventions. (Am J Addict 2019;28:295-302).

Pushing the Limits

Abstract. Longitudinal developmental research is often focused on patterns of change or growth across different (sub)groups of individuals. Particular to some research contexts, developmental inquiries may involve one or more (sub)groups that are small in nature and therefore difficult to properly capture through statistical analysis. The current study explores the lower-bound limits of subsample sizes in a multiple group latent growth modeling by means of a simulation study. We particularly focus on how the maximum likelihood (ML) and Bayesian estimation approaches differ when (sub)sample sizes are small. The results show that Bayesian estimation resolves computational issues that occur with ML estimation and that the addition of prior information can be the key to detect a difference between groups when sample and effect sizes are expected to be limited. The acquisition of prior information with respect to the smaller group is especially influential in this context.

Using Classification Trees to Examine Predictors of Marijuana Use Among a Wide Range of Variables

Background: Young adults have elevated risk for negative marijuana use-related outcomes, and there is heterogeneity among users. Identifying risk factors for marijuana user status will improve understanding of different populations of users, which may inform prediction of individuals most likely to experience negative outcomes. Objectives: To identify predictors of marijuana use initiation in young adults. We simultaneously examined a broad range of potential predictors and all their possible interactions, including constructs that have not been previously studied in substance use initiation research. Methods: Data were repeated cross-sectional survey responses from college students in Colorado (N = 4052, 77% White, 61% female, mean age = 22.77). Measures came from the National College Health Assessment, which assesses numerous health and behavioral constructs. We used recursive partitioning and random forest models to identify predictors of ever having used marijuana out of 206 variables. Results: Classification trees identified engagement in increased alcohol use and sexual behavior as salient correlates of marijuana use initiation. Parsimonious recursive partitioning trees explained a substantial amount of variability in marijuana user status (39% in the full model and 24% when alcohol variables were excluded). Random forest models predicted user status with 74.11% and 66.91% accuracy in the full model and when alcohol variables were excluded, respectively. Conclusions: Results support the use of exploratory analyses to explain heterogeneity among marijuana users and non-users. Since engagement in other health-risk behaviors were salient predictors of use initiation, prevention efforts to reduce harm from marijuana use may benefit from targeting risk factors for health-risk behaviors in general.

Parcellating cognitive heterogeneity in early psychosis-spectrum illnesses: A cluster analysis

Cognitive impairment is argued to represent a core feature of psychosis-spectrum illnesses. However, within-diagnosis heterogeneity is common, and risk factors for poor cognition remain to be examined after statistically accounting for heterogeneity. Accordingly, we used a data-driven technique (cluster analysis) to empirically-derive cognitive clusters across diagnoses and examined whether concurrent substance use or a history of a neurodevelopmental/behavioral disorder differed between clusters. Data from 135 young help-seekers (aged 12-30 years) with a psychosis-spectrum illness were retrospectively analyzed. Ward's hierarchical cluster analysis classified three cognitive clusters characterized by: (1) normal-range; (2) mixed; and (3) grossly-impaired performance. Despite mostly comparable clinical and demographic measures, cluster 1 had superior socio-occupational functioning and the highest estimated premorbid IQ, followed sequentially by clusters 2 and 3. Proportions of cannabis and amphetamine users did not differ significantly across clusters, nor did rates of patients with a neurodevelopmental/behavioral disorder history. Cluster 3 was however comprised of fewer 'risky' drinkers, possibly reflecting reduced opportunity for social drinking associated with cognitive impairment. Estimated premorbid IQ predicted cluster membership (2 vs. 1 & 3 vs. 1), as did clinician-rated socio-occupational functioning and 'not being enrolled in school or tertiary education' (3 vs. 1). Our results suggest that concurrent substance use and history of a neurodevelopmental/behavioral disorder do not adequately explain cluster-level cognitive variance in this sample. Future work should integrate neurobiological measures associated with cognition (e.g. white matter integrity) to discern whether clusters reflect neurobiological subtypes better representative of pathophysiology than present symptom-based classifications.

Interactions between recreational cannabis use and cognitive function: lessons from functional magnetic resonance imaging

Cannabis use is becoming increasingly popular as a growing number of states pass legislation to legalize cannabis and cannabis-derived products for recreational and/or medical purposes. Given the widespread use of cannabis, it is critical to understand the neural consequences related to cannabis use. In this review, we focus on evidence from functional magnetic resonance imaging studies that document acute and residual alterations in brain function during tasks spanning a variety of cognitive domains: executive function, attention and working memory, memory, motor skills, error monitoring, and reward and affective processing. Although it is clear that cannabis affects brain function, the findings are somewhat inconsistent; variables that potentially affect study outcomes are outlined, including a discussion of the impact of chronological age and age of cannabis onset as well as length of abstinence at the time of assessment, which are important considerations when measuring cannabis use patterns. Inherent differences between recreational/adult cannabis use versus use for medical purposes are also discussed, given their importance to public policy decisions.

Regular cannabis use is associated with altered activation of central executive and default mode networks even after prolonged abstinence in adolescent users: Results from a complementary meta-analysis

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Adolescent abstinent cannabis users showed significantly greater activation in the dorsolateral and ventrolateral prefrontal and posterior parietal cortices compared to controls.

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Adolescent users showed increased activation in regions involved in executive functioning, attentional control and the default mode network compared to non-using controls.

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No significant group differences in brain activation observed between abstinent and current adolescent cannabis users.

Whether the effects of cannabis use on brain function persist or recover following abstinence remains unclear. Therefore, using meta-analytic techniques, we examined whether functional alterations measured using fMRI persist in cannabis users abstinent for over 25 days (or 600 h) as evidence suggests that the effects on cognitive performance no longer persist beyond this period. Systematic literature search identified 20 studies, of which, 12 examined current cannabis users (CCU) (361 CCU versus 394 non-cannabis using controls (NU)) and 3 examined abstinent cannabis users (ACU) in 5 separate comparisons (98 ACU versus 106 NU). Studies in ACU were carried out in adolescents and suggest significantly greater activation in components of the central executive and default mode networks in adolescent ACU compared to NU. While this evidence is to be interpreted with caution because studies were carried out in overlapping samples, they indicate a pressing need for independent confirmation whether certain neurofunctional alterations in adolescent cannabis users may persist even after cannabis and its metabolites are likely to have left their bodies.

The gene-environmental architecture of the development of adolescent substance use

BACKGROUND

Using a longitudinal twin design and a latent growth curve/autoregressive approach, this study examined the genetic-environmental architecture of substance use across adolescence.

METHODS

Self-reports of substance use (i.e. alcohol, marijuana) were collected at ages 13, 14, 15, and 17 years from 476 twin pairs (475 boys, 477 girls) living in the Province of Quebec, Canada. Substance use increased linearly across the adolescent years.

RESULTS

ACE modeling revealed that genetic, as well as shared and non-shared environmental factors explained the overall level of substance use and that these same factors also partly accounted for growth in substance use from age 13 to 17. Additional genetic factors predicted the growth in substance use. Finally, autoregressive effects revealed age-specific non-shared environmental influences and, to a lesser degree, age-specific genetic influences, which together accounted for the stability of substance use across adolescence.

CONCLUSIONS

The results support and expand the notion that genetic and environmental influences on substance use during adolescence are both developmentally stable and developmentally dynamic.

The Legalization of Medical/Recreational Marijuana: Implications for School Health Drug Education Programs

BACKGROUND

More than half of US states have legalized medical marijuana. Several states have also legalized it for recreational use. In spite of states' actions, marijuana remains illegal under federal law. It remains to be seen, however, if the Trump administration will enforce federal law in states that have legalized marijuana. For now, it appears the move toward state legalization of marijuana will increase. Because of its legal status, research concerning the medical benefits of marijuana has been limited.

METHODS

We reviewed the literature pertaining to medical use and legalization of marijuana.

RESULTS

Available research shows that marijuana can benefit some conditions. There are also concerns about harmful effects on both individual and public health and whether legalization will lead to increased marijuana use among youth. Each of these elements has implications for school-based drug education programs. Researchers have shown that the 10 states with the highest rate of past month marijuana use by youth all have legalized recreational and/or medical use of marijuana, whereas none of the 10 states with the lowest rate of past month marijuana use by youth, has legalized marijuana. In the debate over legalization schools can potentially serve as a community resource, providing accurate information concerning marijuana.

CONCLUSIONS

Teachers and parents should continue to discourage young people from using marijuana (as well as alcohol, tobacco, and other drugs).

Marijuana matters: reviewing the impact of marijuana on cognition, brain structure and function, & exploring policy implications and barriers to research

The neurobiologic effects of cannabis, commonly referred to as 'marijuana' (MJ), have been studied for decades. The impact of recreational MJ use on cognition and measures of brain function and structure is outlined, and variables influencing study results are discussed, including age of the consumer, patterns of MJ use, variations in MJ potency, and the presence of additional cannabinoids. Although evidence suggests that chronic, heavy recreational MJ use is related to cognitive decrements and neural changes, particularly when use begins in adolescence, findings from studies of recreational MJ users may not be applicable to medical marijuana (MMJ) patients given differences in demographic variables, product selection, and reasons for use. Although additional research is needed to fully understand the impact of MJ and individual cannabinoids on the brain, current findings are beginning to inform public policy, including considerations for age limits, potential limits for some cannabinoids, and guidelines for use. However, barriers continue to impede researchers' ability to conduct studies that will guide policy change and provide vital information to consumers and patients regarding best practices and safest methods for use. The need for information is critical, as legalization of MJ for medical and recreational use is increasingly widespread.

Residual effects of cannabis use in adolescent and adult brains - A meta-analysis of fMRI studies

While numerous studies have investigated the residual effects of cannabis use on human brain function, results of these studies have been inconsistent. Using meta-analytic approaches we summarize the effects of prolonged cannabis exposure on human brain function as measured using task-based functional MRI (fMRI) across studies employing a range of cognitive activation tasks comparing regular cannabis users with non-users. Separate meta-analyses were carried out for studies investigating adult and adolescent cannabis users. Systematic literature search identified 20 manuscripts (13 adult and 7 adolescent studies) meeting study inclusion criteria. Adult analyses compared 530 cannabis users to 580 healthy controls while adolescent analyses compared 219 cannabis users to 224 healthy controls. In adult cannabis users brain activation was increased in the superior and posterior transverse temporal and inferior frontal gyri and decreased in the striate area, insula and middle temporal gyrus. In adolescent cannabis users, activation was increased in the inferior parietal gyrus and putamen compared to healthy controls. Functional alteration in these areas may reflect compensatory neuroadaptive changes in cannabis users.

Analysis of illicit drugs seized in the Province of Florence from 2006 to 2016

Comprehension of illicit drug market's features at local level is useful to plan and to correctly set-up specific informative and contrast activities. In this paper we report trends, purities and consumption estimations of illicit substances available on the Florentine territory from 2006 to 2016. These data were obtained by the analysis of 10,451 samples seized by the Law Enforcement Agencies in case of personal use offence. Analytical procedures consisted in targeted and untargeted analyses by gas chromatography-flame ionization detector, gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry. The most detected substances were: cannabis (78.0%; resin: 51.7%; herb: 26.3%), cocaine (10.4%), opiates (6.6%; heroin: 6.5%; morphine: 0.1%), ketamine (1.4%), amphetamines (1.3%; 3,4-methylenedioxymethamphetamine - MDMA -: 0.7%; methamphetamine: 0.6%; amphetamine: <0.1%) and methadone (1.3%). Cocaine, heroin and methamphetamine purities were higher than their mean values estimated for the Italian and European market, while THC content in cannabis seizures was unexpectedly below the European mean values. Starting from 2015, a total of 5 new psychoactive substances (NPS) were detected in seized material, mainly composed of white powders (pentedrone, 3-methylmethcathinone, 4-fluoroamphetamine, methoxethamine and AB-FUBINACA). Most of the seizures (75.5%) were from young male adults (14-34 years old). These data contribute to highlight new trends in the illicit drug market in the Tuscany area, but also to verify the persistence of old habits of drug consumption, confirming the need for more effective counteraction and prevention plans, especially among young people, where the diffusion of the legal highs is worrisome, also in consideration of the young age and the unconsciousness of the possible health effects.