Trajectories of marijuana use in youth ages 15-25: implications for postsecondary education experiences

Association between cannabis use disorder and greater apathy in adults with HIV

BACKGROUND

Apathy is prevalent among people with HIV (PWH) and is associated with poor clinical outcomes. Cannabis use and Cannabis Use Disorder (CUD) are also disproportionately prevalent among PWH. CUD and younger onset of cannabis use may be linked to apathy in the general population; however, patterns of use most strongly associated with apathy have not been firmly established, and it is unclear whether cannabis use is linked to apathy in PWH.

METHODS

We examined associations in 311 adult PWH between Apathy Evaluation Scale-Self (AES-S) scores and CUD history (current/past/no CUD/no cannabis use) and between AES-S scores and age of CUD onset (adolescent-onset/adult-onset). We also examined robustness of associations to adjustment for depressive symptoms (which may overlap with apathy symptoms) and alcohol use.

RESULTS

Current CUD was associated with greater AES-S scores relative to cannabis users with no CUD history (β = 2.13, 95 % CI = 0.37-3.90, p = 0.018). Adolescent-onset CUD was not associated with greater apathy relative to adult-onset CUD (β = 0.56, 95 % CI = -2.57 - 3.68, p = 0.7). Associations became nonsignificant after adjustment for depressive symptoms, but not after adjustment for alcohol use. Alcohol use was correlated with apathy (r = 0.19, 95 % CI: 0.076-0.29, p = 0.001).

CONCLUSIONS

Cannabis Use Disorder and at-risk alcohol use are associated with apathy among PWH; this finding highlights the need for substance use disorder prevention and treatment among PWH.

Substance Use among School-Going Adolescents and Young Adults in Rural Mpumalanga Province, South Africa

The ongoing public health crisis of substance use among school adolescents and young adults (AYAs) in South Africa is not new in research parlance, amidst the national policy of drug abuse management in schools. In view of no tangible progress to reduce substance use in high schools in the country, we conducted a cross-sectional quantitative study aimed at investigating substance use among adolescents and young adults in the four public high schools selected through multi-stage sampling in rural Mpumalanga province, South Africa. Data on substance use, demographics, household socio-demographics, and related factors were collected via a validated self-administered questionnaire. Hierarchical logistic regression was performed using STATA 18. The study included 402 AYAs aged between 14 and 23 years (18 ± 1 years), and 45% reported substance use in the last twelve months. Alcohol was the most used substance (74%), followed by cigarettes (12%) and cannabis (11%). AYAs used substances out of social influence, curiosity, to find joy, and to eliminate stress, especially in social events, on the streets, and at home, and reported negative physical health outcomes, mainly hallucinations, sleeping disorders, body weakness, and dry mouths. Hierarchical logistic regression showed that the likelihood of substance use was three times in a particular high school (S4) (AOR = 3.93, 95%CI: 1.72-8.99), twice among the grade 12s (AOR = 2.73, 95%CI: 1.46-5.11), over twenty times in the communities with substance availability (AOR = 22.45, 95%CI: 2.75-183.56), almost ten times among AYAs participating in recreational/sports activities (AOR = 9.74, 95%CI: 4.21-22.52), and twice likely to happen in larger households (AOR = 2.96, 95%CI: 1.57-5.58). Prevention and intervention efforts should consider these specific health concerns to develop targeted strategies for mitigating substance use and its adverse consequences in this vulnerable population towards achieving the United Nations' Sustainable Development Goal Target 3.5, which aims to strengthen the prevention and treatment of substance abuse, including narcotic drug abuse and the harmful use of alcohol.

Life-course Accumulated Cannabis Use and Recent Cannabis-related Problems in the Washington Panel Survey

BACKGROUND

Previous studies have only investigated the short-term association of recent cannabis use with cannabis-related problems, without accounting for the onset, duration, and variations in frequency of use in the life-course.

METHODS

We obtained data from the Washington panel survey during 2014-2016. We constructed accumulated lifetime exposure to cannabis use, heavy drinking (5+ drinks on one occasion), and cigarette pack-years from age of onset based on a series of decades-based questions on cannabis use and heavy drinking, and tobacco use history. We used Generalized Estimating Equation with Poisson distribution to investigate the association between accumulated cannabis use and the past-6-month CUDIT score. We adjusted for accumulated heavy drinking and cigarette pack-years, substance co-use variables, demographics, and applied survey weights.

RESULTS

We found strong and statistically significant correlations for the lifetime measures across the four panel surveys, indicating that the life-course measures of cannabis use and heavy drinking were largely reliable. We found a statistically significant relationship between the lifetime accumulated exposure to cannabis and CUDIT. The results were robust to the inconsistencies in reported frequencies and onset age across panel surveys.

CONCLUSIONS

This study established the relationship between lifetime exposure to cannabis and cannabis-related problems in a representative sample of drinkers and marijuana users in Washington state. We have also provided test-retest validity and question details for the decades-based cannabis and heavy drinking measures to facilitate their use in future studies of cannabis and alcohol-related outcomes.

Prevalence of university non-continuation and mental health conditions, and effect of mental health conditions on non-continuation: a systematic review and meta-analysis

BACKGROUND

University non-continuation, also termed as university dropout in literature, is a concern for institutions. Elevated stress levels, mental distress, and psychiatric issues affect academic performance and thus may contribute to non-continuation. There is a lack of systematic reviews exploring the link between mental health and university non-continuation.

AIM

This systematic review aims to bridge this gap, by investigating the prevalence of non-continuation and mental health conditions among university students, and the impact of mental health on university non-continuation.

METHODS

Following PRISMA guidelines this review synthesized data from 67 studies, utilising both narrative synthesis and meta-analytic techniques.

RESULTS

The results revealed that the included studies reported a range of university non-continuation rates (5.9% to 43.6%) with a pooled prevalence of 17.9%, 95% CI [14.2%, 22.3%]. The prevalence of mental health concerns among students varied widely (2.2% to 83.6%), with a pooled prevalence of 26.3%, 95% CI [16.0%, 40.0%]. Depression, OR = 1.143 (95% CI [1.086, 1.203] p<.001), stress, OR = 1.413 (95% CI [1.106, 1.805], p=.006), and other mental health conditions, OR = 1.266 (95% CI [1.133, 1.414], p<.001), were associated with higher non-continuation.

CONCLUSION

Some mental health conditions elevate non-continuation risks, and addressing mental health may enhance student retention in higher education.

The effect of marijuana use in adolescence on college and graduate degree attainment

We estimate the long-term effect of using marijuana in adolescence on college and graduate degree attainment measured approximately 20 years later. We rely on the first two waves (1994-1996) and the fifth wave (2016-2018) of the National Longitudinal Study of Adolescent to Adult Health and estimate instrumental variables models that exploit the network structure at the second degree by using marijuana use status of friends of friends who are not themselves friends of the respondent in order to instrument for the respondent's marijuana use. Our models also include school and grade fixed effects. Marijuana use in adolescence leads to a large reduction in the likelihood of college and graduate degree attainment by the time respondents are aged 33-43 years old.

Tolerance for specific negative affective states and coping-oriented cannabis use motives among college student cannabis users

ObjectiveThe current study examined the unique predictive ability of tolerance of specific negative affective states in relation to frequency of past-month cannabis use and coping-oriented cannabis use motives. Participants: 416 undergraduates who reported past 30 day cannabis use (65.1% female; M_age = 19.46, SD = 2.56). Methods: Participants completed self-report questionnaires for course credit. Results: After accounting for the effects of sex, negative affectivity, and tolerance of other specific negative affective states, lower levels of tolerance for sadness, but not any other negative affective states, significantly predicted more frequent cannabis use in the past 30 days (1.1% unique variance) and coping motives (1.1% unique variance). Conclusions: These findings suggest that cannabis users who have difficulty withstanding sad mood states use cannabis more frequently and are motivated to use cannabis to cope with this specific mood state and not necessarily negative affective states more broadly.

The Protective Role of Grit against Alcohol and Cannabis Use through Young Adulthood

Introduction: Problematic substance use in young adulthood is consistently related to negative outcomes later in life. Understanding the factors that protect against problematic substance provides opportunities for early preventive intervention. We examine the protective role of grit - passion and perseverance for long-term goals - on substance use through young adulthood, a period of heightening risks for substance use. Methods: In this research, we use cross-lagged panel models and data from the Victoria Healthy Youth Survey (N = 477, 52% female) to test the reciprocal within-time associations and the directional relationships between grit (passion and perseverance) and substance use (cannabis and alcohol) across three assessments (6 years, ages 18-29). All models controlled for sex and SES. Results: Significant findings show negative within-time associations between passions and perseverance and cannabis use at T1 (ages 18-24) and at T2 (ages 20-26), and significant, negative within-time associations between passion and perseverance and alcohol use (heavy episodic drinking) at T1 but not at T2. No significant across-time associations between passion and perseverance and substance use were found. Conclusion: Preventive interventions to enhance passion and perseverance may provide important targets for interventions for young adults to reduce current substance use. However, grit did not have an effect beyond the stability of cannabis use or alcohol use over time, suggesting effects may act by substituting proactive goals for current substance use.

Relationship between Everyday Discrimination and Substance Use among Adolescents in Northern Chile

Substance use is a public health problem that affects the normal physical, neurological, and psychological development of adolescents. Apparently, discrimination is an important variable for explaining the initiation and continued use of alcohol and marijuana. Since most research focused on discrimination based on factors, such as race, ethnicity, sexual orientation, or gender faced by minority groups, studies on discrimination faced by the general population remain scarce. This cross-sectional study described the relationship between everyday discrimination and alcohol and marijuana use-related behaviors among Chilean adolescents. It included 2330 students between 12 and 20 years of age from educational establishments in the city of Arica. To evaluate substance use, specifically alcohol and marijuana, the Child and Adolescent Evaluation System (SENA) was used. The Everyday Discrimination scale was used to evaluate discrimination. Age and everyday discrimination can predict up to 11% of the variance in substance use. Reducing the incidence of everyday discrimination may help reduce heavy alcohol and marijuana consumption among adolescents.

Automatic cognitions as mediators of parental influence on adolescent cannabis use

AIMS

Multiple social influences affect cannabis use in adolescents, including parental and peer cannabis use norms. However, the mechanisms of influence underlying these social influences remain unclear. Recent studies have suggested that cognitions about cannabis use and the effects of cannabis may mediate social influences. The current study explored the relationship between automatic self-generated cognitions and their relationship with parental influences on cannabis use in a sample of n = 675 11 to 16-year-old adolescents over three years (Mean Age: 13.96, SD = 0.88, 56.4% female).

METHODS

Participants reported perceptions of parental cannabis use and completed a cannabis word association task (CWAT), an open-ended cannabis outcome expectancy liking (COEL) task, and measures of cannabis use in the past year.

RESULTS

Perceived parental use did not directly predict cannabis use two years later. However, a latent construct loading on both CWAT and COEL scores strongly predicted cannabis use over the following year. Structural modelling demonstrated that the association between previous cannabis use and parental cannabis use and adolescents' cannabis use over the next two years was fully mediated by cognitions.

CONCLUSION

The results of the study are discussed and interpreted through the lens of dual-process theories.

The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review

Background: Cannabis is known to have a broad range of effects on behavior, including experiencing a "high" and tranquility/relaxation. However, there are several adverse behavioral sequalae that can arise from cannabis use, depending on frequency of use, potency (e.g., THC content), age of onset, and cumulative exposure. This systematic review examined evidence for cannabis-related adverse behavioral sequalae in otherwise healthy human subjects. Methods: Following PRISMA guidelines, we conducted a systematic review of cross-sectional and longitudinal studies from 1990 to 2020 that identified cannabis-related adverse behavioral outcomes in subjects without psychiatric and medical co-morbidities from PubMed and PsychInfo searches. Key search terms included "cannabis" OR "tetrahydrocannabinol" OR "cannabidiol" OR "marijuana" AND "anxiety" OR "depression" OR "psychosis" OR "schizophrenia" "OR "IQ" OR "memory" OR "attention" OR "impulsivity" OR "cognition" OR "education" OR "occupation". Results: Our search detected a total of 2,870 studies, from which we extracted 124 relevant studies from the literature on cannabis effects in the non-clinical population. Effects of cannabis on several behavioral sequelae including cognition, motivation, impulsivity, mood, anxiety, psychosis intelligence, and psychosocial functioning were identified. The preponderance of the evidence suggests that frequency of cannabis use, THC (but not CBD) content, age of onset, and cumulative cannabis exposure can all contribute to these adverse outcomes in individuals without a pre-existing medical condition or psychiatric disorder. The strongest evidence for the negative effects of cannabis are for psychosis and psychosocial functioning. Conclusions: Although more research is needed to determine risk factors for development of adverse behavioral sequelae of cannabis use, these findings underline the importance of understanding vulnerability to the adverse effects of cannabis, which has implications for prevention and treatment of problematic cannabis use.

Racial/Ethnic Differences in 30-Year Trajectories of Cannabis Use among Males

Background: Given that cannabis is the most commonly used illicit substance in the US, continuous research on patterns of cannabis use over the life course can help to ensure progress towards improving public health and reducing health inequalities across race/ethnicity. Thus, we examine racial/ethnic differences in cannabis use trajectories among males across two overlapping stages of the life course. Methods: We use data from two companion studies, the Rochester Youth Development Study (RYDS - a longitudinal cohort study that followed participants from adolescence into adulthood), and its intergenerational extension - the Rochester Intergenerational Study. For Life Stage 1, we consider cannabis use during the transition from adolescence to adulthood (spanning ages 13 to 33; 439 Black, 128 White, and 125 Hispanic males). Among these males who became fathers, we consider cannabis use during fatherhood (Life Stage 2 -spanning the period of time when their firstborn child was between the ages of 7 and 17-217 Black, 55 White, and 56 Hispanic males). Ordinal generalized estimating equations were specified to examine cannabis use trajectories during both stages of the males' lives. Results: No significant differences in cannabis use as a function of racial/ethnic group were found during the transition from adolescence to adulthood (Life Stage 1). All groups had a peak of cannabis use in the early to mid-20's followed by a decline in use. During fatherhood (Life Stage 2), cannabis use was stable for all groups, but Black fathers reported more frequent cannabis use on average than Hispanic fathers. Conclusions: The increase in cannabis use well past adolescence for all groups suggests the potential importance of intervention initiatives during the transition to adulthood. The more frequent use of cannabis by Black fathers warrants further study given the impact parental cannabis use can have on offspring.

Cannabis use, depression and suicidal ideation in adolescence: direction of associations in a population based cohort

BACKGROUND

To clarify the direction of the association between frequency of cannabis use, depressive symptoms and suicidal ideation from 15 to 20 years using cross-lagged analyses.

METHOD

We included 1606 adolescents from the province of Québec followed since 1997 with information on frequency of cannabis use (none/monthly/weekly), depression (defined as being in the top 10% symptoms) and serious suicidal ideation at ages 15, 17 and 20 years.

RESULTS

The prevalence of weekly cannabis use increased from 7.0% at age 15 years to 15.6% by age 20 years. Adolescents who reported using cannabis weekly at one age were 11 to 15 times more likely to continue using cannabis over time. In longitudinal cross-lagged analyses, weekly cannabis use at age 15 was associated with greater odds (OR=2.19, 95% CI=1.04-4.58) of suicidal ideation two years later. However, other substance use (alcohol, tobacco, other drugs) fully explained this association. Further, depression predicted subsequent weekly cannabis use, even after adjusting for comorbid other substance use (eg, for depression at 15 years predicting cannabis use at 17 years: OR=2.30, 95% CI=1.19-4.43).

LIMITATIONS

Quantity of cannabis consumed was not measured.

CONCLUSION

Findings suggest that depressive symptoms in adolescence may represent a risk factor for weekly cannabis consumption, which once initiated is likely to remain chronic. Weekly cannabis use increased risk for suicidal ideation, but not independently from other substance use including alcohol, tobacco and other drugs.

Youth marijuana use: a review of causes and consequences

The legalization of medical and recreational marijuana has raised concerns about a potential increase in the availability and illegal use of marijuana by adolescent minors. To better understand the etiology, patterns, and consequences of adolescent marijuana use, this article reviews high quality, methodologically rigorous, longitudinal studies that focus on the role of personality factors such as sensation-seeking in the etiology of use, developmental trajectories of use and the effects of chronic use, potential gateway effects of marijuana on other illicit drugs, and its role in the onset of psychiatric disorders in adolescents and young adults. Implications are discussed in terms of mechanisms that account for initial and continued use of marijuana by adolescents, how use is associated with key developmental milestones and adult role socialization, and the potential of marijuana use during adolescence in furthering later drug involvement.

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).

Child Maltreatment, Relationship with Father, Peer Substance Use, and Adolescent Marijuana Use

This longitudinal prospective study examined the relationship between child maltreatment as per reports to child protective services (CPS) and adolescent self-reported marijuana use, and the association between relationships with mothers and fathers and use of marijuana. The association between relationships with parents early in childhood (ages 6-8 years) and during adolescence with adolescent marijuana use were also probed. Another aim examined whether relationships with parents moderated the link between child maltreatment and youth marijuana use. The sample included 702 high risk adolescents from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN), a consortium of 5 studies related to maltreatment. Children were recruited at age 4 or 6 years together with their primary caregiver. Some were recruited due to their risk for child maltreatment, others were already involved with CPS, and children in one site had been placed in foster care. Logistic regression analysis was performed using youth self-report of marijuana use as the criterion variable and child maltreatment and the relationships with parents as predictor variables, controlling for youths' perceptions of peer substance use and parental monitoring, parental substance use, race/ethnicity, sex and study site. Approximately half the youth had used marijuana. Most of them described quite positive relationships with their mothers and fathers. Participant marijuana Use was associated with a poorer quality of relationship with mother during adolescence, and with peer and parental substance use. A better relationship with father, but not mother, during adolescence attenuated the connection between Child Maltreatment and youth Marijuana Use.

Effects of Adolescent Cannabis Use on Motivation and Depression: A Systematic Review

Purpose of review

This article reviews recent behavioral and neuroimaging studies to elucidate whether adolescent cannabis use is related to reduced motivation and increased risk of depression.

Recent findings

Recent work suggests that heavy adolescent cannabis use predicts poorer educational outcomes, often presumed to reflect reduced academic motivation, as well as increased levels of depressive symptoms. However, evidence of a link between cannabis use and general motivation was lacking. Factors such as concurrent alcohol and tobacco use, trajectories of cannabis use during adolescence, and cannabis-related changes in underlying neurocircuitry may impact associations among cannabis use, motivation, and depression.

Summary

Heavy adolescent cannabis use is associated with poorer educational outcomes and increased levels of depressive symptoms. The role of depression in how cannabis may affect motivation, broadly, is not yet clear, as most studies have not examined associations among all three constructs. Future work should explore possible overlap between cannabis effects on motivation and depression, and clarify the temporality of these associations.

Sexual minority women and Cannabis use: The serial impact of PTSD symptom severity and coping motives

Sexual minority women (SMW) report greater rates of cannabis use. Posttraumatic stress disorder (PTSD) symptom severity is related to greater cannabis use among SMW, and it is theorized that this is due to SMW using cannabis in an attempt to manage negative affectivity associated with PTSD symptoms. However, this is the first known study to test this hypothesis. Among undergraduate women who endorsed lifetime cannabis use (N = 439, 10.5% self-identified SMW), SMW reported greater rates of cannabis use, more frequent cannabis use, greater coping-motivated use, and greater PTSD symptom severity than heterosexual women. Serial mediation analyses revealed that SMW reported more frequent cannabis use via the serial effect of PTSD symptom severity and coping-motivated cannabis use. Given the high rates of trauma exposure and cannabis use among SMW, findings suggest that SMW could benefit from exposure-based interventions in addition to cognitive behavioral skills that would teach them more adaptive strategies to manage negative affect associated with trauma exposure and PTSD symptoms.

Is the Sum Greater than its Parts? Variations in Substance-Related Consequences by Conjoint Alcohol-Marijuana Use Patterns

Alcohol and marijuana are the most commonly used substances for college-attending young adults. This study evaluated differences in substance-specific consequence attribution by alcohol-marijuana use patterns (concurrent alcohol and marijuana [CAM; use of both substances, not at same time] and simultaneous [SAM; use of both, at same time]) as well as alcohol-only (AO). First-year college students with prior alcohol use (N = 610, 50.9% women, 71% White, M_age = 18) completed an online assessment of past-three-month substance use, including SAM, and related consequences. Results indicated that polydrug (SAM and CAM) users reported greater alcohol involvement and earlier alcohol initiation than AO, and polydrug use was associated with more alcohol-related problems, including sexual risk taking and alcohol-related blackouts. When restricted to SAM/CAM users, logistic regressions indicated that SAM users reported an increased incidence in two marijuana-related problems relative to CAM (driving after using and academic difficulties), but lower rates of social problems. SAM users were also less likely to attribute substance-related social problems to alcohol. Overall, findings highlight variations that exist within alcohol-marijuana polydrug users and show areas to consider for intervention development and future research.

Substance Use, Academic Performance, and Academic Engagement Among High School Seniors

BACKGROUND

Substance use is prevalent and is associated with academic performance among adolescents. Few studies have examined the association between abstinence from all substances and academic achievement.

METHODS

Data from a nationally representative sample of 9578 12th graders from the 2015 Monitoring the Future survey were analyzed to examine relationships between abstinence from substance use and 4 academic variables: skipping school, grades, academic self-efficacy, and emotional academic engagement. Participants were categorized as lifetime non-users, former users, and past-year users based on the use of 14 substances.

RESULTS

Approximately one-fourth of participants had never used cigarettes, alcohol, or other drugs during their lifetime, and 8%wt used at least one substance during their lifetime but not during the past year. Adjusting for demographic variables, past-year substance users had 2.71 greater odds of skipping school during the past month than lifetime non-users and 1.74 greater odds of having low grades. Lifetime non-users reported greater academic self-efficacy and emotional academic engagement than past-year users.

CONCLUSIONS

Many 12th graders have abstained from all substance use during their lifetime, and these adolescents experience better academic outcomes than their substance-using peers. Substance use prevention programs should be evaluated as a way to promote academic achievement.

Age of First Marijuana Use and Its Impact on Education Attainment and Employment Status

With the increased prevalence of marijuana use among youth, the increase in state legalization, and changing social norms in the United States, it is important to understand the long-term impact of marijuana use initiation. This study examined whether age of first marijuana use is associated with educational attainment and employment status. Data from 5,988 adults aged 26 to 49 years who participated in the 2015 National Survey on Drug Use and Health were used in the current study. Logistic regression analyses were used to examine the odds of graduating from high school and being employed. Controlling for demographics, persons with late-early first use had significantly higher odds of graduating from high school and being employed compared with persons with early first use. Results underscore the importance of early prevention for youth aged 15 and younger and have implications for intervention and policy development.

Cannabis Use: Neurobiological, Behavioral, and Sex/Gender Considerations

PURPOSE OF REVIEW

To summarize the current literature on the effects of cannabinoids in humans and to discuss the existing literature on the sex- and gender-related differences in the effects of cannabinoids.

RECENT FINDINGS

Cannabis and its constituent cannabinoids are associated with risk of addiction, cognitive deficits and mood/psychotic disorders. Preclinical and emerging clinical data suggest greater sensitivity to the effects of cannabinoids in women.

SUMMARY

Cannabis is one of the most commonly used drugs with increasing rates of use. Women in particular may be at a greater risk of adverse outcomes given the previously described "telescoping effect" of substance use in women. Human data examining the sex- and gender-related differences in the effects of cannabinoids and factors underlying these differences are very limited. This represents a critical gap in the literature and needs to be systematically examined in future studies.

Developmental pathways of adolescent cannabis use: Risk factors, outcomes and sex-specific differences

BACKGROUND

Characterizing patterns of adolescent cannabis use (CU), as well as risk factors and outcomes uniquely associated with these pathways is essential for informing treatment and prevention efforts. Yet, few studies have examined these issues among youth at-risk of engaging in problematic cannabis use. Further, research accounting for use of other substances or sex differences in patterns of CU remains exceedingly sparse.

METHODS

Trajectory-based modeling was used to identify underlying CU pathways among a predominantly Hispanic (90%) sample of at-risk youth (n = 401; 46% female) across adolescence (ages∼14-18), controlling for baseline substance use and participant demographics. Adolescent psychopathology (i.e., conduct disorder, attention deficit hyperactivity disorder, anxiety, and depression) was examined as a predictor and outcome of CU.

RESULTS

Three trajectories of adolescent CU were identified, with most youth (74%) engaging in relatively "low" levels of use, followed by ∼12% exhibiting an early-initiating "chronic" course, and 14% "escalating" in use. Although boys and girls both experienced increased levels of CU across adolescence, boys were more likely to exhibit escalating and chronic patterns of use. Findings revealed unique associations between adolescent CU pathways and facets of psychopathology; most notably, the relatively robust and bidirectional association between CU trajectories and conduct problem symptoms.

CONCLUSIONS

Specific facets of psychopathology may confer unique associations with CU across development, including the initiation and exacerbation of CU during adolescence.

Recovery schools for improving behavioral and academic outcomes among students in recovery from substance use disorders: a systematic review

This Campbell systematic review examines the effects of recovery schools on student behavioral and academic outcomes, compared to the effects of non-recovery schools. The review summarizes evidence from one quasi-experimental study (with a total of 194 participants) that had potential serious risk of bias due to confounding. Sizable portions of youth are in recovery from substance use disorders, and many youth will return to use after receiving substance use treatment. Youth spend most of their waking hours at school, and thus schools are important social environments for youth in recovery from substance use disorders. Recovery schools have been identified as educational programs that may help support youth in recovery from substance use disorders. This review focused on two types of recovery schools: RHSs, which are schools that award secondary school diplomas and offer a range of therapeutic services in addition to standard educational curricula; and CRCs, which offer therapeutic and sober support services on college campuses. This review looked at whether recovery schools (RHSs or CRCs) affect academic success and substance use outcomes among students, compared to similar students who are not enrolled in recovery schools.

Plain language summary

There is insufficient evidence to know whether recovery high schools and collegiate recovery communities are effective: Evidence that recovery high schools (RHSs) may improve academic and substance use outcomes is based on the findings from a single study with a serious risk of bias.The review in brief: Very limited evidence addresses the effectiveness of recovery high schools (RHSs). There is no rigorous evidence on the effectiveness of collegiate recovery communities (CRCs).It is unclear whether CRCs are effective in promoting academic success and reducing substance use among college students.What is the aim of this review?: This Campbell systematic review examines the effects of recovery schools on student behavioral and academic outcomes, compared to the effects of non-recovery schools. The review summarizes evidence from one quasi-experimental study (with a total of 194 participants) that had potential serious risk of bias due to confounding.What are the main findings of this review?: Sizable portions of youth are in recovery from substance use disorders, and many youth will return to use after receiving substance use treatment. Youth spend most of their waking hours at school, and thus schools are important social environments for youth in recovery from substance use disorders. Recovery schools have been identified as educational programs that may help support youth in recovery from substance use disorders.This review focused on two types of recovery schools: RHSs, which are schools that award secondary school diplomas and offer a range of therapeutic services in addition to standard educational curricula; and CRCs, which offer therapeutic and sober support services on college campuses.This review looked at whether recovery schools (RHSs or CRCs) affect academic success and substance use outcomes among students, compared to similar students who are not enrolled in recovery schools.What studies are included?: The included study of recovery high schools used a controlled quasi-experimental pretest-posttest design and reported on the following outcomes: grade point average, truancy, school absenteeism, alcohol use, marijuana use, other drug use, and abstinence from alcohol/drugs. The included study focused on a sample of U.S. high school students. There were no eligible studies of CRCs.What do the findings of this review mean?: Findings from this review indicate insufficient evidence on the effects of recovery schools on student well-being. Although there is some indication RHSs may improve academic and substance use outcomes, this is based on the findings from a single study. There is no available evidence on the effects of CRCs.No strong conclusions can be drawn at this time, given the lack of available evidence on RHSs and CRCs, and the serious risk of bias in the one RHS study included in the review. The evidence from this review suggests there is a clear need for additional rigorous evaluations of recovery school effects prior to widespread implementation.How up-to-date is this review?: The review authors searched for studies until September 2018. This Campbell systematic review was published in 2018.

Executive Summary/Abstract

BACKGROUND: Substance use disorders (SUDs) among youth are a major public health problem. In the United States, for example, the incidence of SUDs increases steadily after age 12 and peaks among youth ages 18-23 (White, Evans, Ali, Achara-Abrahams, & King, 2009). Although not every youth who experiments with alcohol or illicit drugs is diagnosed with an SUD, approximately 7-9% of 12-24 year olds in the United States were admitted for public SUD treatment in 2013 (Substance Abuse and Mental Health Services Administration [SAMHSA], 2016). Recovery from an SUD involves reduction or complete abstinence of use, defined broadly as "voluntarily sustained control over substance use, which maximises health and wellbeing and participation in the rights, roles and responsibilities of society" (UK Drug Policy Commission, 2008). However, SUDs are often experienced as chronic conditions; among youth who successfully complete substance use treatment, approximately 45-70% return to substance use within months of treatment discharge (Anderson, Ramo, Schulte, Cummins, & Brown, 2007; Brown, D'Amico, McCarthy, & Tapert, 2001; Ramo, Prince, Roesch, & Brown, 2012; White et al., 2004). Thus, multiple treatment episodes and ongoing recovery supports after treatment are often necessary to assist with the recovery process (Brown et al., 2001; Ramo et al., 2012; White et al., 2004).Success and engagement at school and in postsecondary education are critical to healthy youth development. For youth in recovery from SUDs, school attendance, engagement, and achievement build human capital by motivating personal growth, creating new opportunities and social networks, and increasing life satisfaction and meaning (Keane, 2011; Terrion, 2012; 2014). Upon discharge from formal substance use treatment settings, schools become one of the most important social environments in the lives of youth with SUDs. Healthy school peer environments can enable youth to replace substance use behaviors and norms with healthy activities and prosocial, sober peers. Conversely, many school environments may be risky for youth in recovery from SUDs due to perceived substance use among peers, availability of drugs or alcohol, and substance-approving norms on campus (Centers for Disease Control [CDC], 2011; Spear & Skala, 1995; Wambeam, Canen, Linkenbach, & Otto, 2014).Given the many social and environmental challenges faced by youth in recovery from substance use, recovery-specific institutional supports are increasingly being linked to educational settings. The two primary types of education-based continuing care supports for youth in recovery, defined under the umbrella term of "recovery schools" for this review, are recovery high schools (RHSs) and collegiate recovery communities (CRCs). RHSs are secondary schools that provide standard high school education and award secondary school diplomas, but also include therapeutic programming aimed at promoting recovery (e.g., group check-ins, community service, counseling sessions). CRCs also provide recovery oriented support services (e.g., self-help groups, counseling sessions, sober dorms) for students, but are embedded within larger college or university settings. The primary aims of RHSs and CRCs are to promote abstinence and prevent relapse among students, and thus ultimately improve students' academic success.OBJECTIVES: This review summarized and synthesized the available research evidence on the effects of recovery schools for improving academic success and behavioural outcomes among high school and college students who are in recovery from substance use. The specific research questions that guided the review are as follows: 1. What effect does recovery school attendance (versus attending a non-recovery or traditional school setting) have on academic outcomes for students in recovery from substance use? Specifically (by program type): a. For recovery high schools: what are the effects on measures of academic achievement, high school completion, and college enrolment?b. For collegiate recovery communities: what are the effects on measures of academic achievement and college completion?2. What effect does recovery school attendance have on substance use outcomes for students in recovery from substance use? Specifically, what are the effects on alcohol, marijuana, cocaine, or other substance use?3. Do the effects of recovery schools on students' outcomes vary according to the race/ethnicity, gender, or socioeconomic status of the students?4. Do the effects of recovery schools on students' outcomes vary according to existing mental health comorbidity status or juvenile justice involvement of the students? SEARCH METHODS: We aimed to identify all published and unpublished literature on recovery schools by using a comprehensive and systematic literature search. We searched multiple electronic databases, research registers, grey literature sources, and reference lists from prior reviews; and contacted experts in the field.SELECTION CRITERIA: Studies were included in the review if they met the following criteria:Types of studies: Randomized controlled trial (RCT), quasi-randomized controlled trial (QRCT), or controlled quasi-experimental design (QED).Types of participants: Students in recovery from substance use who were enrolled part-time or full-time in secondary (high school) or postsecondary (college or university) educational institutions.Types of interventions: Recovery schools broadly defined as educational institutions, or programs at educational institutions, developed specifically for students in recovery and that address recovery needs in addition to academic development.Types of comparisons: Traditional educational programs or services that did not explicitly have a substance use recovery focus.Types of outcome measures: The review focused on primary outcomes in the following two domains: academic performance (e.g., achievement test scores, grade-point average, high school completion, school attendance, college enrolment, college completion) and substance use (alcohol, marijuana, cocaine, heroin, stimulant, mixed drug use, or other illicit drug use). Studies that met all other eligibility criteria were considered eligible for the narrative review portion of this review even if they did not report outcomes in one of the primary outcome domains.Other criteria: Studies must have been reported between 1978 and 2016. The search was not restricted by geography, language, publication status, or any other study characteristic.DATA COLLECTION AND ANALYSIS: Two reviewers independently screened all titles and abstracts of records identified in the systematic search. Records that were clearly ineligible or irrelevant were excluded at the title/abstract phase; all other records were retrieved in full-text and screened for eligibility by two independent reviewers. Any discrepancies in eligibility assessments were discussed and resolved via consensus. Studies that met the inclusion criteria were coded by two independent reviewers using a structured data extraction form; any disagreements in coding were resolved via discussion and consensus. If members of the review team had conducted any of the primary studies eligible for the review, external and independent data collectors extracted data from those studies. Risk of bias was assessed using the ROBINS-I tool for non-randomized study designs (Sterne, Higgins, & Reeves, 2016).Inverse variance weighted random effects meta-analyses were planned to synthesize effect sizes across studies, as well as heterogeneity analysis, subgroup analysis, sensitivity analysis, and publication bias analysis. However, these synthesis methods were not used given that only one study met the inclusion criteria for the review. Instead, effect sizes (and their corresponding 95% confidence intervals) were reported for all eligible outcomes reported in the study.RESULTS: Only one study met criteria for inclusion in the review. This study used a QED to examine the effects of RHSs on high school students' academic and substance use outcomes. No eligible studies examining CRCs were identified in the search.The results from the one eligible RHS study indicated that after adjusting for pretest values, students in the RHS condition reported levels of grade point averages (= 0.26, 95% CI [-0.04, 0.56]), truancy (= 0.01, 95% CI [-0.29, 0.31]), and alcohol use (= 0.23, 95% CI [-0.07, 0.53]) similar to participants in the comparison condition. However, students in the RHS condition reported improvements in absenteeism (= 0.56, 95% CI [0.25, 0.87]), abstinence from alcohol/drugs (OR = 4.36, 95% CI [1.19, 15.98]), marijuana use (= 0.51, 95% CI [0.20, 0.82]), and other drug use (= 0.45, 95% CI [0.14, 0.76]).Overall, there was a serious risk of bias in the one included study. The study had a serious risk of bias due to confounding, low risk of bias due to selection of participants into the study, moderate risk of bias due to classification of interventions, inconclusive risk of bias due to deviations from intended interventions, inconclusive risk of bias due to missing data, moderate risk of bias in measurement of outcomes, and low risk of bias in selection of reported results.AUTHORS' CONCLUSIONS: There is insufficient evidence regarding the effectiveness of RHSs and CRCs for improving academic and substance use outcomes among students in recovery from SUDs. Only one identified study examined the effectiveness of RHSs. Although the study reported some beneficial effects, the results must be interpreted with caution given the study's potential risk of bias due to confounding and limited external validity. No identified studies examined the effectiveness of CRCs across the outcomes of interest in this review, so it is unclear what effects these programs may have on students' academic and behavioral outcomes.The paucity of evidence on the effectiveness of recovery schools, as documented in this review, thus suggest the need for caution in the widespread adoption of recovery schools for students in recovery from SUDs. Given the lack of empirical support for these recovery schools, additional rigorous evaluation studies are needed to replicate the findings from the one study included in the review. Furthermore, additional research examining the costs of recovery schools may be needed, to help school administrators determine the potential cost-benefits associated with recovery schools.

Triple trajectories of alcohol use, tobacco use, and depressive symptoms as predictors of cannabis use disorders among urban adults

Heavy cannabis use is associated with a wide array of physical, mental, and functional problems. Therefore, cannabis use disorders (CUDs) may be a major public health concern. Given the adverse health consequences of CUDs, the present study seeks to find possible precursors of CUDs. The current study consisted of 5 waves of data collection from the Harlem Longitudinal Development Study. Among 816 participants, about half are African Americans (52%), and the other half are Puerto Ricans (48%). We used Mplus to obtain the triple trajectories of alcohol use, tobacco use, and depressive symptoms. Logistic regression analyses were then conducted to examine the associations between the trajectory groups and CUDs. The 5 trajectory groups were (1) moderate alcohol use, high tobacco use, and high depressive symptoms (MHH; 12%); (2) moderate alcohol use, high tobacco use, and low depressive symptoms (MHL; 26%); (3) moderate alcohol use, low tobacco use, and low depressive symptoms (MLL; 18%); (4) low alcohol use, no tobacco use, and high depressive symptoms (LNH; 11%); and (5) low alcohol use, no tobacco use, and low depressive symptoms (LNL; 33%). The MHH, MHL, MLL, and LNH trajectory groups were associated with an increased likelihood of having CUDs compared to the LNL trajectory group after controlling for a number of confounding factors (e.g., CUDs in the late 20s). The findings of the current longitudinal study suggest that treatments designed to reduce or quit drinking as well as smoking and to relieve depressive symptoms may reduce the prevalence of CUDs. (PsycINFO Database Record

Trajectories of cannabis-related associative memory among vulnerable adolescents: Psychometric and longitudinal evaluations

Indirect tests of memory associations relevant to cannabis have been shown to be useful in explaining and predicting adolescent cannabis use habits. This study sought to increase the understanding of adolescent cannabis-related associative memory and cannabis use behavior over time. A longitudinal sample of alternative high school students (N = 775) was assessed yearly for 3 years. The study first conducted extensive longitudinal measurement analyses of the cannabis-related word association test (WAT) applying contemporary psychometric models. Second, the study examined the longitudinal trajectories of cannabis-related associative memory and cannabis use and their contemporaneous and longitudinal relationships. Results showed that the cannabis-related WAT provided strong evidence of sound psychometric properties. Longitudinal change in cannabis-related associative memory was best described by modeling either a linearly decreasing trajectory or two separate trajectories: During middle adolescence, levels of cannabis-related associative memory were highest and stable but then gradually decreased toward late adolescence. Moreover, cannabis-related associative memory was contemporaneously predictive of cannabis use within ages 15 to 19 while controlling for the underlying growth process of cannabis use and time-invariant covariates (TICs) of gender and lifetime concurrent use of alcohol and cigarettes. Partial support of longitudinal prediction of cannabis use was also obtained from age 17 to 18 and age 19 to 20 while adjusting for growth in cannabis use and the TICs. These results demonstrated that predictive effects of cannabis-related memory associations on cannabis use were detected within some of the 1-year age spans and were consistent within ages across adolescent years. (PsycINFO Database Record

Development of Marijuana Use Among Juvenile Offenders and Its Relevance for Predicting Problematic Binge Drinking: A Dual Trajectory Analysis Approach

This study builds on past research to examine the association of engagement in consistently high binge drinking behavior in adolescence with the concurrent development of marijuana use and to better understand the development of marijuana use during adolescence among a sample of juvenile offenders. This research used group-based trajectory analysis to examine heterogeneity in the development of marijuana use and dual trajectory analysis to examine the relevance of trajectories for predicting concurrent problematic binge drinking. A seven-group model best fit the marijuana use data. Marijuana use in adolescence predicted increased odds of assignment to the heavy chronic binge drinking group. The heavy chronic marijuana use group was overwhelmingly the best predictor of assignment to this group. Juvenile offenders are at risk of engagement in marijuana use and problematic levels of marijuana use. Engagement in marijuana use predicts higher odds of problematic binge drinking behavior during adolescence.

Cannabis Involvement and Nonsuicidal Self-Injury: A Discordant Twin Approach

OBJECTIVE

Cannabis use, particularly at an early age, has been linked to suicidal thoughts and behavior, but minimal work has examined the association between cannabis use and lifetime nonsuicidal self-injury (NSSI). The current study aims to characterize the overlap between lifetime and early cannabis use and NSSI and to examine genetic and environmental mechanisms of this association.

METHOD

Adult male and female twins from the Australian Twin Registry (N = 9,583) were used to examine the odds of NSSI associated with lifetime cannabis use and early cannabis use (i.e., <17 years of age). These associations were also examined within monozygotic (MZ) twins discordant for cannabis use and MZ twins discordant for early cannabis use. Analyses were replicated in an independent sample of female twins (n = 3,787) accounting for the age at onset of cannabis use and NSSI.

RESULTS

Lifetime cannabis use (odds ratio [OR] = 2.84, 95% CI [2.23, 3.61]) and early cannabis use were associated with increased odds of NSSI (OR = 2.15, 95% CI [1.75, 2.65]), and this association remained when accounting for covariates. The association was only significant, however, in MZ twin pairs discordant for early cannabis use (OR = 3.20, 95% CI [1.17, 8.73]). Replication analyses accounting for the temporal ordering of cannabis use and NSSI yielded similar findings of nominal significance.

CONCLUSIONS

Results suggest that NSSI is associated with cannabis involvement via differing mechanisms. For lifetime cannabis use, the lack of association in discordant pairs suggests the role of shared genes and family environment. However, in addition to such shared familial influences, person-specific and putatively causal factors contribute to the relationship between early cannabis use and NSSI. Therefore, delaying the onset of cannabis use may reduce exposure to influences that exacerbate vulnerabilities to NSSI.

Freshman year alcohol and marijuana use prospectively predict time to college graduation and subsequent adult roles and independence

OBJECTIVE

This study examined how freshman year substance use prospectively predicted time to college graduation, and whether delayed graduation predicted postponed adoption of adult roles and future substance use.

PARTICIPANTS

Participants were part of a longitudinal study that began in 2004. The first analyses focused on freshman year (N = 2,050). The second analyses corresponded to a subset of participants at age 27 (N = 575).

METHODS

Measures included self-reported substance use, adult role adoption, and university reported graduation dates.

RESULTS

Results indicated that frequent binge drinking and marijuana use during freshman year predicted delayed college graduation. Those who took longer to graduate were more likely to have lower incomes and were less likely to obtain a graduate degree. Taking 5-6 years to graduate was associated with greater likelihood of alcohol-related problems.

CONCLUSIONS

Findings support the importance of interventions during freshman year of college to decrease substance use and promote timely graduation.

Alcohol and Illicit Drug Use Are Important Factors for School-Related Problems among Adolescents

The aim of this study was to investigate the association between alcohol and drug use, and school-related problems measured by low grade point average (GPA) and high school attendance. We also examined potential confounding effects from mental health problems. Although the issue is not new within current literature, the present study has its strengths in a large number of participants and the utilization of registry-based data on school-related functioning. A cross-sectional design is employed in this study using data from a large population-based sample of adolescents, youth@hordaland, in a linkage to official school registry data, and the current study presents data from N = 7,874. The main independent variables were alcohol use and drug use, as well as potential alcohol- and drug-related problems. The dependent variables were registry-based school attendance and grades. All the alcohol- and drug measures included were consistently associated with low GPA (Odds ratios (OR) ranging 1.82–2.21, all p < 0.001) and high levels of missed days from school (ORs ranging 1.79–3.04, all p < 0.001) and high levels of hours missed from school (ORs ranging 2.17–3.44, all p < 0.001). Even after adjusting for gender, age, socioeconomic status and mental health problems all the associations between alcohol and illicit drug use and the school-related outcomes remained statistically significant. Increasing number of indications on alcohol/drug-related problems and increasing levels of alcohol consumption were associated with more negative school-related outcomes. The results suggest that alcohol- and drug use, and particularly alcohol/drug-related problems, are important factors for school-related problems independently of mental health problems.

Frequent marijuana use and driving risk behaviours in Canadian youth

Background

A better understanding of the relations between patterns of marijuana use and driving risks in young adulthood is needed.

Methods

Secondary analyses of self-report data from the Victoria Healthy Youth Survey. Youth (baseline ages 12 to 18; N=662; 52% females) were interviewed biannually (on six occasions) from 2003 to 2013 and classified as abstainers (i.e., used no marijuana in past 12 months), occasional users (i.e., used at most once per week), and frequent users (i.e., used more than once a week).

Results

In the frequent user group, 80% of males and 75% of females reported 'being in a car driven by driver (including themselves) using marijuana or other drugs in the last 30 days', 64% of males and 33% of females reported that they were 'intoxicated' with marijuana while operating a vehicle and 50% of males and 42% of females reported being in a car driven by a driver using alcohol. In addition, 28% of occasional users and also a small proportion of abstainers reported 'being in a car driven by a driver using marijuana or other drugs in the last 30 days'.

Interpretation

The high frequency of driving risk behaviours, particularly for frequent users, suggest that plans for legalization of recreational use should anticipate the costs of preventive education efforts that present an accurate picture of potential risks for driving. Youth also need to understand risks for dependence, and screening for and treatment of marijuana use disorders is needed.

Childhood academic ability in relation to cigarette, alcohol and cannabis use from adolescence into early adulthood: Longitudinal Study of Young People in England (LSYPE)

OBJECTIVES

Our aim was to determine the association between childhood academic ability and the onset and persistence of tobacco, alcohol and cannabis use across adolescence in a representative sample of English schools pupils. Previous research has produced conflicting findings.

DESIGN

Data from 7 years of the Longitudinal Study of Young People in England (LSYPE), 2004-2010 (age 13/14-19/20).

SETTING

Self-completion questionnaires during home visits, face-to-face interviews and web-based questionnaires.

PARTICIPANTS

Data from 6059 participants (3093 females) with information on academic ability around age 11 and health behaviours from age 13/14 to 16/17 (early adolescence) and from age 18/19 to 19/20 (late adolescence).

OUTCOME MEASURES

Regularity of cigarette smoking, alcohol drinking and cannabis use from early to late adolescence.

RESULTS

In multinomial logistic regression models adjusting for a range of covariates, the high (vs low) academic ability reduced the risk of persistent cigarette smoking (RR=0.62; CI 95% 0.48 to 0.81) in early adolescence. High (vs low) academic ability increased the risk of occasional (RR=1.25; CI 95% 1.04 to 1.51) and persistent (RR=1.83; CI 95% 1.50 to 2.23) regular alcohol drinking in early adolescence and persistent (RR=2.28; CI 95% 1.84 to 2.82) but not occasional regular alcohol drinking in late adolescence. High (vs low) academic ability was also positively associated with occasional (RR=1.50; CI 95% 1.22 to 1.83) and persistent (RR=1.91; CI 95% 1.57 to 2.34) cannabis use in late adolescence.

CONCLUSIONS

In a sample of over 6000 young people in England, high childhood academic at age 11 is associated with a reduced risk of cigarette smoking but an increased risk of drinking alcohol regularly and cannabis use. These associations persist into early adulthood, providing evidence against the hypothesis that high academic ability is associated with temporary 'experimentation' with substance use.

Longitudinal patterns of marijuana use across ages 18-50 in a US national sample: A descriptive examination of predictors and health correlates of repeated measures latent class membership

BACKGROUND

This descriptive study identified latent classes of longitudinal marijuana use from ages 18 through 50 among a national sample; examined covariate associations with class membership regarding use/non-use, use intensity, and use duration; and described associations between identified latent classes and age 50 health outcomes.

METHODS

The study involved collection and primary analysis of data from 9831 individuals first surveyed as 12th graders in the national Monitoring the Future study and followed through modal age 50. Repeated measures latent class analysis was used to identify latent classes based on self-reported past 12-month marijuana use.

RESULTS

Seven latent classes of marijuana use from ages 18 to 50 were identified including Non-users (44%), two classes characterized by shorter-term use patterns (totaling 28%), and four classes characterized by longer-term moderate or heavy use (totaling 28%). Use reduction appeared particularly likely during early and late 20s. Gender, parental education, alcohol/cigarette use, religious commitment, and marital status differentiated use/non-use, use intensity, and use duration after high school. In non-causal models controlling for covariates, longer-term marijuana use classes (where use extended into the late 20s or beyond) were associated with significantly higher odds of negative health outcomes at age 50.

CONCLUSIONS

Approximately 28% of the national sample reported longer-term moderate/heavy marijuana use, which was associated with negative health outcomes at age 50. The early and late 20s may be especially important periods for marijuana use prevention and intervention efforts, which may be strengthened by recognition of characteristics that appear to have significant associations with persistent use.

Marijuana use and service utilization among adolescents 7 years post substance use treatment

BACKGROUND

In an environment of increasingly liberal attitudes towards marijuana use and legalization, little is known about long-term trajectories of marijuana use among clinical samples of adolescents, and how these trajectories relate to health services utilization over time.

METHODS

Latent growth curve analysis was used to identify distinct trajectories of marijuana use in a clinical sample of adolescents (N=391) over 7 years post substance use treatment in an integrated health system. We examined psychiatric problems and polysubstance use associated with the identified trajectory groups using general linear models. Nonlinear mixed-effects logistic regressions were used to examine associations between health services use and the trajectory groups.

RESULTS

We identified three marijuana use trajectory groups: (1) Abstinent (n=117); (2) Low/Stable use (n=174); and (3) Increasing use (n=100). Average externalizing and anxiety/depression scores were significantly lower over time for the Abstinent group compared to the Increasing and Low/Stable groups. The Low Stable and the Increasing group had fewer psychiatric visits over time (p<0.05) and the Low/Stable group used more substance use treatment services over time compared with the Abstinent group (p<0.001).

CONCLUSIONS

Treated adolescents showed distinct marijuana use patterns, one of which indicated a group of adolescents at risk of increased use over time. These individuals have greater psychiatric and polysubstance use over time, but may not be accessing needed services.

Clearing the haze: the complexities and challenges of research on state marijuana laws

As states increasingly liberalize marijuana laws, high-quality research is needed that will inform the public and policymakers about the health and societal impact of these laws. However, there are many challenges to studying marijuana policy, including the heterogeneity of the drug and its use, the variability in the laws and their implementation from state to state, the need to capture a wide variety of relevant outcomes, and the poorly understood influence of marijuana commercialization. Furthermore, current instruments generally fail to distinguish between types of users and lack accurate and detailed measures of use. This review provides a background on marijuana laws in the United States and an overview of existing policy research, discusses methodological considerations when planning analysis of state marijuana laws, and highlights specific topics needing further development and investigation.

[The adolescent abstainers: A risk group?]

OBJECTIVE

If abstinence from substance in adolescents may nowadays be regarded statistically as a deviant behavior, what is its significance from a developmental point of view? The aim of this article is to examine the mental health characteristics and the social integration of adolescent abstainers.

METHODS

A comprehensive literature review of epidemiological studies including data on adolescent abstainers was conducted.

RESULTS

Compared to the abundant literature devoted to adolescent substance abusers, few studies report data on adolescent abstainers. In addition, many methodological problems limit their interpretability and their comparison. However that may be, this body of work suggests that if abstinence may be due to something intrinsic about the individual (such as psychosocial adjustment difficulties, personality traits or gender), many other environmental factors (such as family background of temperance, cultural practices, upbringing or religion) may determine abstaining behavior. By this way, from a psychopathological angle, adolescent abstainers certainly constitute a more heterogeneous group than the adolescent substance abusers. Some of them are quite psychologically healthy, whereas others are more socially withdrawn and may suffer from emotional disorders.

CONCLUSION

In terms of prevention, these data highlight the need for longitudinal prospective studies examining the psychosocial status of adolescent abstainers, their antecedents, their outcome and their motivations.

Alcohol and marijuana use trajectories in a diverse longitudinal sample of adolescents: examining use patterns from age 11 to 17 years

AIMS

We tested race/ethnic differences in alcohol and marijuana (AM) trajectories (comprising an intercept term, reflecting overall probability of use, and a slope term, reflecting change in probability of use) during adolescence, whether AM use trajectories predicted high school outcomes, and whether outcomes differed by race/ethnicity after controlling for trajectory of AM use.

DESIGN

This longitudinal study involved 6509 youth from 16 middle schools in Southern California surveyed from age 11.5 (2008) to age 17 (2015) years; all surveys assessed AM use, and the final survey also examined high school outcomes.

SETTING

Youth completed five surveys in middle school and two on-line surveys in high school.

PARTICIPANTS

The sample was 50% male and 80% non-white.

MEASUREMENTS

Intercept (at 2.75 years post-baseline) and slope of AM use were examined as outcomes for race/ethnic differences. AM use trajectories were examined as predictors of academic performance and unpreparedness, social functioning, mental and physical health and delinquency.

FINDINGS

We found differences in trajectories of use by race/ethnicity, with white youth reporting a higher overall intercept of alcohol use compared to all other groups (versus Asian P < 0.001, black P = 0.001, multi-ethnic P = 0.008). Overall, examination of trajectories of use showed that adolescents with a higher alcohol use intercept term reported greater academic unpreparedness (P < 0.001) and delinquency (P < 0.001) at wave 7 in high school. In addition, youth with a higher intercept for marijuana use reported greater academic unpreparedness (P < 0.001) and delinquency (P < 0.001), and poorer academic performance (P = 0.032) and mental health (P = 0.002) in high school. At wave 7, compared to white youth, Hispanic and multi-ethnic youth reported poorer academic performance (P < 0.001 and P = 0.034, respectively); Asian, black and Hispanic youth reported higher academic unpreparedness (P < 0.001, P = 0.019, and P = 0.001); and Asian youth and multi-ethnic youth reported poorer physical health (P = 0.012 and P = 0.018) controlling for AM use.

CONCLUSIONS

Greater AM use was associated with worse functioning in high school for all youth. After controlling for AM use, non-white youth reported worse outcomes in high school for academics and health.

Developmental trajectories of adolescent cannabis use and their relationship to young adult social and behavioural adjustment: A longitudinal study of Australian youth

This study aimed to identify distinct developmental trajectories (sub-groups of individuals who showed similar longitudinal patterns) of cannabis use among Australian adolescents, and to examine associations between trajectory group membership and measures of social and behavioural adjustment in young adulthood. Participants (n=852, 53% female) were part of the International Youth Development Study. Latent class growth analysis was used to identify distinct trajectories of cannabis use frequency from average ages 12 to 19, across 6 waves of data. Logistic regression analyses and analyses of covariance were used to examine relationships between trajectory group membership and young adult (average age: 21) adjustment, controlling for a range of covariates. Three trajectories were identified: abstainers (62%), early onset users (11%), and late onset occasional users (27%). The early onset users showed a higher frequency of antisocial behaviour, violence, cannabis use, cannabis-related harms, cigarette use, and alcohol harms, compared to the abstinent group in young adulthood. The late onset occasional users reported a higher frequency of cannabis use, cannabis-related harms, illicit drug use, and alcohol harms, compared to the abstinent group in young adulthood. There were no differences between the trajectory groups on measures of employment, school completion, post-secondary education, income, depression/anxiety, or alcohol use problems. In conclusion, early onset of cannabis use, even at relatively low frequency during adolescence, is associated with poorer adjustment in young adulthood. Prevention and intervention efforts to delay or prevent uptake of cannabis use should be particularly focussed on early adolescence prior to age 12.

Marijuana use trajectories during college predict health outcomes nine years post-matriculation

BACKGROUND

Several studies have linked marijuana use with a variety of health outcomes among young adults. Information about marijuana's long-term health effects is critically needed.

METHODS

Data are from a ten-year study of 1253 young adults originally recruited as first-year college students and assessed annually thereafter. Six trajectories of marijuana use during college (Non-Use, Low-Stable, Early-Decline, College-Peak, Late-Increase, Chronic) were previously derived using latent variable growth mixture modeling. Nine health outcomes assessed in Year 10 (modal age 27) were regressed on a group membership variable for the six group trajectories, holding constant demographics, baseline health status, and alcohol and tobacco trajectory group membership.

RESULTS

Marijuana trajectory groups differed significantly on seven of the nine outcomes (functional impairment due to injury, illness, or emotional problems; psychological distress; subjective well-being; and mental and physical health service utilization; all ps<.001), but not on general health rating or body mass index. Non-users fared better than the Late-Increase and Chronic groups on most physical and mental health outcomes. The declining groups (Early-Decline, College-Peak) fared better than the Chronic group on mental health outcomes. The Late-Increase group fared significantly worse than the stable groups (Non-Use, Low-Stable, Chronic) on both physical and mental health outcomes.

CONCLUSIONS

Even occasional or time-limited marijuana use might have adverse effects on physical and mental health, perhaps enduring after several years of moderation or abstinence. Reducing marijuana use frequency might mitigate such effects. Individuals who escalate their marijuana use in their early twenties might be at especially high risk for adverse outcomes.

Characteristics of Child Maltreatment and Adolescent Marijuana Use: A Prospective Study

There has been increasing acceptance of marijuana use in the United States in recent years, and rates among adolescents have risen. At the same time, marijuana use during adolescence has been linked to an array of health and social problems. Maltreated children are at risk for marijuana use, but the relationships among characteristics of maltreatment and marijuana use are unclear. In this article, we examine how the type and the extent of maltreatment are related to the level of adolescent marijuana use. Data analyses were conducted on a subsample of maltreated adolescents (n = 702) from the Longitudinal Studies of Child Abuse and Neglect project. Approximately half the sample had used marijuana, and maltreatment was associated with its use. Multivariate regression models showed that being male, extensive maltreatment, and peer marijuana use were associated with heavy use of marijuana. These findings suggest the importance of comprehensively assessing children's maltreatment experiences and their peers' drug use to help prevent or address possible marijuana use in these high-risk adolescents.

The academic consequences of marijuana use during college

Although several studies have shown that marijuana use can adversely affect academic achievement among adolescents, less research has focused on its impact on postsecondary educational outcomes. This study utilized data from a large longitudinal cohort study of college students to test the direct and indirect effects of marijuana use on college grade point average (GPA) and time to graduation, with skipping class as a mediator of these outcomes. A structural equation model was evaluated taking into account a variety of baseline risk and protective factors (i.e., demographics, college engagement, psychological functioning, alcohol and other drug use) thought to contribute to college academic outcomes. The results showed a significant path from baseline marijuana use frequency to skipping more classes at baseline to lower first-semester GPA to longer time to graduation. Baseline measures of other drug use and alcohol quantity exhibited similar indirect effects on GPA and graduation time. Over time, the rate of change in marijuana use was negatively associated with rate of change in GPA, but did not account for any additional variance in graduation time. Percentage of classes skipped was negatively associated with GPA at baseline and over time. Thus, even accounting for demographics and other factors, marijuana use adversely affected college academic outcomes, both directly and indirectly through poorer class attendance. Results extend prior research by showing that marijuana use during college can be a barrier to academic achievement. Prevention and early intervention might be important components of a comprehensive strategy for promoting postsecondary academic achievement.

The relationship of higher education to substance use trajectories: variations as a function of timing of enrollment

OBJECTIVE

This study examined the association between time to enrollment into postsecondary education and trajectories of heavy episodic drinking (HED) and marijuana use using a prospective longitudinal study.

METHOD

Participants included 391 postsecondary students (55% female) drawn from the Victoria Healthy Youth Survey, a five-wave, multi-cohort sample interviewed biennially between 2003 and 2011. Using piecewise latent growth modeling, we compared changes in the trajectories of HED and marijuana use before and after postsecondary enrollment across three groups of young adults: (a) direct entrants (enrolled directly out of high school), (b) gap entrants (took a year off), and (c) delayed entrants (took longer than a year off).

RESULTS

Heavy drinking increased after enrollment for direct entrants and gap entrants and decreased for delayed entrants. Marijuana use increased after enrollment for direct entrants, and decreased for gap entrants and delayed entrants. Yet, overall levels of marijuana use were significantly higher among the gap and delay entrants over time compared with direct entrants. Group differences in heavy drinking appeared to reflect age-related changes in drinking patterns. However, differences in marijuana use may reflect pre-existing inequities in access to higher education across groups.

CONCLUSIONS

The association between postsecondary education and increased substance use may be limited to students who enroll at a postsecondary institution directly out of high school. However, students who delay enrollment have higher levels of substance use before enrollment, as well as lower high school grades and socioeconomic status compared with direct entrants, and may be particularly vulnerable to long-term substance use problems and degree noncompletion.

The Effect of Types of Postsecondary Education on Drinking: Does Age of Enrollment Matter?

Using longitudinal data from early adolescence through young adulthood, this study examined the association between different types of postsecondary education (PSE), age of enrollment in PSE, and the trajectory of alcohol use for Canadian young adults (N = 521). Trajectories of alcohol use were compared across young adults at 2-year colleges, 4-year universities, transfer programs (started at a 2-year college and transferred to a 4-year university), and terminal high school graduates. While initial findings revealed significant differences in the drinking trajectories of 2-year college students and 4-year university students, all differences were accounted for by variability in the age of enrollment. Overall, there were few differences in heavy drinking across types of institutions, but younger students increased their alcohol use more than older students following enrollment. However, young adults who do not attend PSE may be at greatest risk for heavy drinking over time.