Adolescent Cannabis Research Articles

Study links adolescent cannabis use with psychosis

A cohort study of 11,868 adolescents found that those who used cannabis at any point reported a greater number of psychosis symptoms, and more distress from those symptoms, compared to teens who never used cannabis. This study, “Psychosis Spectrum Symptoms Before and After Adolescent Cannabis Use Initiation,” published last week in JAMA Psychiatry, sought to answer the question of whether the cannabis use is an effort to self‐medicate underlying psychosis, or contributes to increased vulnerability to psychosis. Findings were consistent with the self‐medication hypothesis. The researchers concluded that it is important to account for both shared vulnerability, and self‐medication effects, when modeling cannabis‐psychosis risk associations. The study used data from 5 waves across 4 years of followup from the Adolescent Brain Cognitive Development (ABCD) Study.

Psychosis Spectrum Symptoms Before and After Adolescent Cannabis Use Initiation

Adolescent cannabis use has been consistently posited to contribute to the onset and progression of psychosis. However, alternative causal models may account for observed associations between cannabis use and psychosis risk, including shared vulnerability for both cannabis use and psychosis or efforts to self-medicate distress from psychosis spectrum symptomology. To test 3 hypotheses that may explain cannabis-psychosis risk associations by modeling psychosis spectrum symptom trajectories prior to and after cannabis initiation across adolescent development (approximately 10-15 years of age). This cohort study used data from 5 waves across 4 years of follow-up from the Adolescent Brain Cognitive Development (ABCD) Study. The ABCD study is an ongoing large-scale, longitudinal study of brain development and mental and physical health of children in the US launched in June 2016. Data are collected from 21 research sites. The study included data from 11 868 adolescents aged 9 to 10 years at baseline. Three participants were excluded from the present analysis owing to missing data. Data analysis was performed from September 2023 to July 2024. Discontinuous growth curve modeling was used to assess trajectories of psychosis spectrum symptoms before and after cannabis initiation. Control variables considered for this investigation were age, sex, internalizing and externalizing symptoms, socioeconomic status, parental mental health, and other substance use. Among the 11 858 participants at wave 1, the mean (SD) age was 9.5 (0.5) years; 6182 (52%) participants were male. Consistent with a shared vulnerability hypothesis, adolescents who used cannabis at any point during the study period reported a greater number of psychosis spectrum symptoms (B, 0.86; 95% CI, 0.68-1.04) and more distress (B, 1.17; 95% CI, 0.96-1.39) from psychosis spectrum symptoms relative to those who never used cannabis. Additionally, consistent with a self-medication hypothesis, the number of psychosis spectrum symptoms (B, 0.16; 95% CI, 0.12-0.20) and distress (B, 0.23; 95% CI, 0.21-0.26) from psychosis spectrum symptoms increased in the time leading up to cannabis initiation. We observed mixed evidence for an increase in psychosis symptoms after cannabis initiation (ie, contributing risk hypothesis). The findings underscore the importance of accounting for shared vulnerability and self-medication effects when modeling cannabis-psychosis risk associations.

Clinician perspectives on barriers and facilitators to the treatment of adolescent cannabis use: A qualitative study

IntroductionCannabis use among adolescents is prevalent, and clinicians who work with adolescents have unique insights about how to treat cannabis use in this population. MethodsThis qualitative study interviewed 32 clinicians from addiction medicine recovery services (AMRS), the emergency department (ED), mental health (MH), and pediatrics in an integrated healthcare system to understand their perspectives and experiences regarding barriers and facilitators to treating adolescent cannabis use. The analysis was developed using thematic analysis of interviews. ResultsThirty-two clinicians (Mean age = 45.9, SD =7.6; 56.3 % Female; 56.3 % White) were recruited from AMRS (n = 13; 41.9 %), the ED (n = 7; 22.5 %), MH (n = 7; 22.5 %) and pediatrics (n = 5; 16.1 %). Clinicians discussed several key barriers and facilitators of treating adolescent cannabis use. Facilitators include the use of multiple screening tools for adolescent cannabis use (i.e., self-report and toxicology testing) which provide more comprehensive information; patient-centered treatment approaches; and discussing cannabis use in the context of adolescents' mental health. Barriers discussed included adolescents' and parents' minimization of adolescent cannabis use risks. Several factors were discussed as potential facilitators or barriers, depending on context, including the influence of peers, virtual treatment, and parental involvement or lack thereof in treatment. ConclusionsInterviews with clinicians who work with adolescents across settings highlighted factors that serve as barriers and facilitators to treating adolescent cannabis use. These findings have important implications for guiding future research and intervention efforts, including the inclusion of universal screening practices, addressing stigma, reducing adolescents' and parents' minimization of cannabis use-related harms, and improving adolescent and parent engagement in treatment.

Parental Monitoring and Its Association With Alcohol, Tobacco Cigarettes, and Cannabis Initiation in the United States Adolescent Population

PurposeLimiting time with friends (LTWF), a facet of parental monitoring, may be protective for newly incident adolescent alcohol, tobacco cigarette, and cannabis use. MethodsWe extended epidemiological evidence based on estimates from nationally representative samples of US adolescents aged 12–17 years, across 18 years of independent samples of the National Survey on Drug Use and Health (2002–2019). We estimated the prevalence of always LTWF, and odds ratios examining incident alcohol, tobacco cigarette, and cannabis use by LTWF within age and cohort. ResultsThe prevalence of always LTWF decreased with older age within study year and cohort. The odds of alcohol initiation were lower among youth reporting their parents were always LTWF. The odds of tobacco cigarette and cannabis initiation were lower among younger youth reporting their parents were always LTWF. DiscussionFuture research is needed to fully understand the influence of LTWF on incident substance use, particularly for older adolescents.

Association of Local Cannabis Policy and Retail Availability With Cannabis Use and Problematic Cannabis Use Among Adolescents in Northern California.

Objectives. To examine whether local cannabis policies and retail availability are associated with cannabis use and problematic cannabis use (PCU) among adolescents in Northern California. Methods. The sample comprised adolescents aged 13 to 17 years screened for past-year cannabis use during well-child visits in 2021. Exposures included local bans on cannabis storefront retailers, policy protectiveness, and retail proximity and density. Outcomes included self-reported past-year cannabis use and PCU diagnoses. Modified Poisson regression models adjusted for sociodemographics. Results. The sample (n = 103 134) was 51.1% male with a median age of 15 years (interquartile range [IQR] = 14-16 years); 5.5% self-reported cannabis use, and 0.3% had diagnosed PCU. Adolescents had a lower prevalence of cannabis use in jurisdictions that banned storefront retailers (adjusted prevalence rate [APR] = 0.857; 95% confidence interval [CI] = 0.814, 0.903 vs allowed), banned delivery (APR = 0.751; 95% CI = 0.710, 0.795 vs allowed), or had more policy protections (APR range = 0.705-0.800). Lower PCU prevalence was also found among those in jurisdictions that banned (vs allowed) storefront retailers (APR = 0.786; 95% CI = 0.629, 0.983) or delivery (APR = 0.783; 95% CI = 0.616, 0.996). Longer drive time and lower density of storefront retailers were associated with a lower cannabis use prevalence. Conclusions. More protective cannabis policies and less retail availability were associated with a lower prevalence of adolescent cannabis use and PCU. (Am J Public Health. 2024;114(S8):S654-S663. https://doi.org/10.2105/AJPH.2024.307787).

Preadolescent individual, familial, and social risk factors associated with longitudinal patterns of adolescent alcohol, cannabis, and other illicit drug use in a population-representative cohort.

The aim of this exploratory study was to identify developmental patterns of adolescent concurrent alcohol, cannabis, and other illicit drug use and their preadolescent individual, familial, and social risk factors in a population-representative cohort from the province of Quebec, Canada (N = 1,593; 48.4% male). Age 12-17 years self-reports of alcohol, cannabis, and other illicit drug use were collected. Latent growth modeling was used to analyze developmental patterns of single- or polysubstance use (SU/PSU), and multinomial regression examined their association with risk factors assessed at age 10-12 years. Five developmental patterns were revealed, including nonusers (12.8% sample) and four classes reflecting different levels of SU/PSU (5.8%-37.5%), varying in severity based on onset, frequency, and type of substances used. Boys and girls were similarly represented throughout SU/PSU patterns. In comparisons with nonusers, several preadolescent risk factors were associated with increasing severity of SU/PSU. Possibly indexing fearlessness/disinhibition, low internalizing symptoms were common to all adolescent users. An earlier onset of substance use and increasing use of substances throughout adolescence were linked with having deviant peers for all user classes but later-onset users. Preadolescents manifesting externalizing problems and exposed to family adversity in addition to the above risk factors showed the earliest onset and most frequent adolescent SU/PSU, especially those also exposed to less appropriate parenting. Consistent with the developmental model of substance use, the nature, number, and severity of preadolescent risk factors distinguished between the type and severity of SU/PSU patterns in adolescence and call for a consistent strategy of universal, selective, and indicated preventive interventions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Adolescent alcohol drinking and cannabis use: Longitudinal, and cohort analysis of high school students in Australia

Aims: The final year of high school is a challenging phase, during which substance use is common. We conducted longitudinal and cohort comparisons on the levels of alcohol and cannabis use among final year (Year 12) high school students compared to the previous year. Design: Longitudinal and cohort analyses of self-reported survey data. Setting: Ten independent schools across South-East Queensland, Australia. Participants: Year 12 students in 2020 (n = 1024) were compared (a) longitudinally with themselves in Year 11; and (b) to the 2019 Year 12 cohort (n = 632). Measures: Self-reported alcohol and cannabis use. Analyses adjusted for socio-demographic, parental, and schooling variables. Findings: Longitudinally, Year 12 students of 2020 had higher odds of having six or more drinks per occasion, monthly or more often, and reporting lifetime cannabis use, compared to themselves in 2019. However, they were not more likely to drink alcohol weekly or more often in 2020 versus 2019. Compared to the 2019 cohort, the 2020 cohort had higher odds of drinking weekly or more often, having six or more drinks per occasion monthly, and reporting lifetime cannabis use. Conclusions: The 2020 cohort of Year 12 adolescents were more likely to engage in heavy drinking and cannabis use, compared to themselves the previous year, and compared to the previous cohort. Greater alcohol consumption and likelihood of cannabis use among the 2020 cohort might be explained by increased age and impacts of the COVID-19 pandemic. Future research to monitor if this is a continuing trend is warranted.

Supplemental Material for Preadolescent Individual, Familial, and Social Risk Factors Associated With Longitudinal Patterns of Adolescent Alcohol, Cannabis, and Other Illicit Drug Use in a Population-Representative Cohort

Supplemental Material for Preadolescent Individual, Familial, and Social Risk Factors Associated With Longitudinal Patterns of Adolescent Alcohol, Cannabis, and Other Illicit Drug Use in a Population-Representative Cohort

Does maternal education moderate the relationship between adolescent cannabis use and mental health in early adulthood?

Socioeconomic disadvantage has been associated with cannabis use and poor mental health. It is therefore hypothesised that lower maternal education, a proxy for socioeconomic disadvantage, may increase the risk of cannabis-related mental health and substance use consequences. A total of 5099 participants from the Avon Longitudinal Study of Parents and Children reported cannabis use via questionnaires at 16 or 18. Logistic regression was used to examine the relationship between any and regular (weekly or more) adolescent cannabis use with depression, anxiety, psychotic experiences, and problematic cannabis use at age 24. Maternal education was included as an effect modifier. Missing data were addressed through multiple imputation using chained equations. In total, 36.5% of participants reported adolescent cannabis use and, of these, 14% reported regular use. Adolescent cannabis use was associated with an increased likelihood of anxiety and problematic cannabis use; however, there was little evidence of moderation by maternal education. Regular cannabis use was associated with an increased likelihood of problematic cannabis use, with little evidence of moderation by maternal education. There was weak evidence that the association between regular cannabis use and depression (interaction p-value = 0.024) and anxiety (interaction p-value = 0.056) was stronger in people with high maternal education. Adolescent cannabis use is associated with increased risk of anxiety and cannabis use disorder, but there was insufficient evidence that childhood socioeconomic position (proxied by maternal education) modifies this relationship. Improved public health messages for all adolescents about these risks may be warranted.

The many forms of cannabis use: Prevalence and correlates of routes of administration among nationally representative samples of U.S. adult and adolescent cannabis users

BackgroundCannabis legalization has made cannabis accessible via dispensaries which sell a wide variety of cannabis products. Importantly, the various routes of administration are associated with differing consequences. As such, it’s crucial to understand the prevalence and correlates of different cannabis products. Unfortunately, research has yet to examine the prevalence of certain forms of cannabis use, and little is known about the prevalence of using multiple forms of cannabis, and whether individual-level factors are associated with using different forms of cannabis. MethodsThe current study uses data from the 2022 National Survey on Drug Use and Health (NSDUH) to examine the prevalence and correlates of eight different types of cannabis use (smoking, vaping, eating/drinking, dabbing, drops/lozenges, topical, pills, and other), as well as a cannabis variety scale, on samples of adult and adolescent cannabis users. ResultsThe results suggest that certain routes of administration are more prevalent than others and that these patterns are fairly consistent between adults and adolescents. Similarly, for both adults and adolescents, the majority of users used more than one cannabis product. Lastly, several individual-level factors are associated with the various forms of cannabis use and many of these associations vary by the route of administration examined. ConclusionsThe results of the current study demonstrate that there are differences among cannabis users. If we can develop an understanding of who uses the various forms of cannabis, we could identify the users of the more dangerous forms and provide these individuals with more resources.

Adolescent THC impacts on mPFC dopamine-mediated cognitive processes in male and female rats.

Adolescent cannabis use is linked to later-life changes in cognition, learning, and memory. Rodent experimental studies suggest Δ9-tetrahydrocannabinol (THC) influences development of circuits underlying these processes, especially in the prefrontal cortex, which matures during adolescence. We determined how 14 daily THC injections (5mg/kg) during adolescence persistently impacts medial prefrontal cortex (mPFC) dopamine-dependent cognition. In adult Long Evans rats treated as adolescents with THC (AdoTHC), we quantify performance on two mPFC dopamine-dependent reward-based tasks-strategy set shifting and probabilistic discounting. We also determined how acute dopamine augmentation with amphetamine (0, 0.25, 0.5mg/kg), or specific chemogenetic stimulation of ventral tegmental area (VTA) dopamine neurons and their projections to mPFC impact probabilistic discounting. AdoTHC sex-dependently impacts acquisition of cue-guided instrumental reward seeking, but has minimal effects on set-shifting or probabilistic discounting in either sex. When we challenged dopamine circuits acutely with amphetamine during probabilistic discounting, we found reduced discounting of improbable reward options, with AdoTHC rats being more sensitive to these effects than controls. In contrast, neither acute chemogenetic stimulation of VTA dopamine neurons nor pathway-specific chemogenetic stimulation of their projection to mPFC impacted probabilistic discounting in control rats, although stimulation of this cortical dopamine projection slightly disrupted choices in AdoTHC rats. These studies confirm a marked specificity in the cognitive processes impacted by AdoTHC exposure. They also suggest that some persistent AdoTHC effects may alter amphetamine-induced cognitive changes in a manner independent of VTA dopamine neurons or their projections to mPFC.

Lower distress intolerance is associated with higher glutathione levels in adolescent cannabis users

Cannabis (CB) use and psychological stressors increase oxidative stress in the brain. Glutathione (GSH), the most abundant antioxidant in the brain, protects against oxidative stress. Furthermore, distress intolerance, the inability to tolerate psychological or physiological stress is a risk factor for CB use. The relationship between CB use, brain GSH levels and distress intolerance remains unknown. Therefore, we examined GSH levels in the anterior cingulate cortex (ACC), as a measure of oxidative stress, and its relationship with distress intolerance in adolescent CB users and healthy controls (HC).Sixteen HC and 17 CB-using adolescents were included in the analysis. GSH levels were measured in the ACC using a metabolite-edited proton magnetic resonance spectroscopy sequence on a 3T scanner. Distress intolerance was assessed using the Distress Intolerance Index (DII) and CB use was evaluated using a structured clinical interview.In the CB group, lower CSF-corrected GSH levels in the ACC were correlated with higher DII scores. However, no significant between group differences were observed for ACC CSF-corrected GSH levels or on DII scores. No significant correlations were observed in the HC group between GSH levels and DII.Our findings suggests that the association between lower GSH levels and greater distress intolerance in CB users might reflect alterations in the balance between protective and oxidative stress conditions linked to the ability to tolerate distress. Further examination into this relationship can provide important insights into neurobiological correlates and risk factors associated with CB use to help inform preventive and treatment targets in the future.

Adolescent THC impacts on mPFC dopamine-mediated cognitive processes in male and female rats.

Adolescent cannabis use is linked to later-life changes in cognition, learning, and memory. Rodent experimental studies suggest Δ9-tetrahydrocannabinol (THC) influences development of circuits underlying these processes, especially in the prefrontal cortex, which matures during adolescence. We determined how 14 daily THC injections (5mg/kg) during adolescence persistently impacts medial prefrontal cortex (mPFC) dopamine-dependent cognition. In adult Long Evans rats treated as adolescents with THC (AdoTHC), we quantify performance on two mPFC dopamine-dependent reward-based tasks-strategy set shifting and probabilistic discounting. We also determined how acute dopamine augmentation with amphetamine (0, 0.25, 0.5 mg/kg), or specific chemogenetic stimulation of ventral tegmental area (VTA) dopamine neurons and their projections to mPFC impacts probabilistic discounting. AdoTHC sex-dependently impacts acquisition of cue-guided instrumental reward seeking, but has minimal effects on set-shifting or probabilistic discounting in either sex. When we challenged dopamine circuits acutely with amphetamine during probabilistic discounting, we found reduced discounting of improbable reward options, with AdoTHC rats being more sensitive to these effects than controls. In contrast, neither acute chemogenetic stimulation of VTA dopamine neurons nor pathway-specific chemogenetic stimulation of their projection to mPFC impacted probabilistic discounting in control rats, although stimulation of this cortical dopamine projection slightly disrupted choices in AdoTHC rats. These studies confirm a marked specificity in the cognitive processes impacted by AdoTHC exposure. They also suggest that some persistent AdoTHC effects may alter amphetamine-induced cognitive changes in a manner independent of VTA dopamine neurons or their projections to mPFC.

Association between cannabis use and nicotine use persistence among adolescents

IntroductionProspective associations of adolescent cannabis use with nicotine use persistence are not well characterized but are important for informing prevention and policy. This study examined the association of 4 types of cannabis product use with subsequent persistent nicotine product use among adolescents. MethodsWe used prospective data from an adolescent cohort (14–17 years) from Southern California surveyed at baseline and at approximately 6-month follow-up (2022–2023). We incorporated three mutually non-exclusive analytic samples comprised of individuals with baseline past 6-month use of: (1) any nicotine product (N=308 [mean[SD] age = 16.3[0.6] years]), (2) e-cigarettes (n = 276), and (3) any combustible tobacco product (n = 137). Baseline past 6-month cannabis smoking, vaping, edible use, cannabidiol [CBD] or hemp product use, and any cannabis product use (yes/no) were separately modeled as predictors of past 6-month persistent use of any nicotine products, e-cigarettes, and combustible tobacco at follow-up. ResultsBaseline use of any cannabis product was associated with increased odds of persistent use of e-cigarettes or any nicotine product (adjusted odds ratio[OR] range: 1.96–2.66). Cannabis smoking was positively associated with persistent any nicotine product use (adjusted OR=2.19, 95 % CI=1.20–4.02). Cannabis smoking, vaping, and edible use predicted persistent use of e-cigarettes (adjusted OR range: 2.22–2.79). Cannabis product use did not predict combustible tobacco use persistence. Associations of CBD/hemp product use with nicotine use persistence outcomes were all non-significant. ConclusionsAdolescents who use cannabis may be at elevated risk for persistent nicotine use.

Amygdala volume and depression symptoms in young adolescents who use cannabis

IntroductionBoth cannabis use and depressive symptomology increase in prevalence throughout adolescence. Concurrently, the brain is undergoing neurodevelopment in important limbic regions, such as the amygdala. Prior research indicates the amygdala may also be related to cannabis use and depressive symptoms. We aimed to investigate the effects of adolescent cannabis use on amygdala volumes as well as the interaction of cannabis use and amygdala morphometry on depressive symptoms in youth. MethodTwo-hundred-twenty-four participants (ages 12–15), balanced by sex assigned at birth, were selected from a sub-sample of the Adolescent Brain Cognitive Development (ABCD) Study based on hair toxicology and self-report measures of cannabis use. Participants positive for cannabinoids in hair and/or self-reported cannabis use were demographically matched to youth with no self-reported or confirmed cannabis use. The guardians of these youth reported depression symptoms on the Child Behavioral Checklist. Linear mixed effect models were run investigating cannabis use group on amygdala volumes bilaterally, controlling for whole brain volume and random effects of scanner type. Additional analyses examined cannabis group status and bilateral amygdala volume on depression symptoms. ResultsCannabis use was not significantly associated with amygdala volume but was associated with increased depressive symptoms (p<0.01). Cannabis group interacted with amygdala volume, such that individuals with smaller volumes had increased depressive symptoms within the cannabis group (p’s<0.01–0.02). ConclusionAberrations in amygdala volume based on cannabis use were not found in early adolescence; however, more depressive symptoms were related to cannabis group. Youth who use cannabis and have smaller amygdala volumes were at increased risk for depressive symptomology, suggesting potential neurovulnerabilities to cannabis use.

Academic orientation and cannabis use-findings from a population-based study of Swedish adolescents in upper secondary school.

To examine the association between academic orientation and frequent cannabis use among Swedish adolescents in upper secondary school and include pupils from introductory programs (IPs), a large group of adolescents previously overlooked in research on adolescent cannabis use. We used cross-sectional data from two anonymous school surveys carried out in upper secondary school in 2021. The samples consisted of pupils from all academic orientations, and the analysis included 3151 pupils in higher education preparatory programs (HEPs), 1010 pupils in vocational programs (VPs), and 819 pupils in IPs. The association between the exposure academic orientation and the outcome frequent (21+ times) cannabis was analyzed using multi-level mixed-effects Poisson regression. Estimates from the first model showed a significant (P < 0.05) 2.45 times higher risk of frequent cannabis use among pupils in IPs compared with in HEPs [incidence rate ratio (IRR) 2.45, 95% confidence interval (CI) 1.28-4.66] and 82% higher in VPs (IRR 1.82, 95% CI 1.09-3.04) compared with in HEPs. However, the associations between academic orientation and frequent (21+ times) cannabis use were attenuated and no longer significant when socioeconomic status, truancy, school dissatisfaction, and early onset of substance use were adjusted for. There was a higher risk of frequent (21+ times) cannabis use among pupils in IPs, and this differential was explained by higher exposure to risk factors in this group. This result is important from a policy perspective as it provides knowledge of a previously neglected risk group for frequent cannabis use.

Short-term mindsets show co-development with adolescent delinquency, but not with adolescent cannabis use

Short-term mindsets show co-development with adolescent delinquency, but not with adolescent cannabis use

Short-term mindsets show co-development with adolescent delinquency, but not with adolescent cannabis use.

Guided by General Theory of Crime and Psychosocial Maturity Hypothesis, we investigated co-development between short-term mindsets (impulsivity and future orientation) and risk behaviors (cannabis use and delinquency). Parallel process latent growth modeling on three-wave data from ethnically diverse Swiss adolescents (N = 1365; Mage 13.67 years, 48.6% female), showed baseline-level associations between short-term mindsets and risk behaviors, and between the two risk behaviors. Additionally, correlated change (co-development) existed between short-term mindsets-particularly impulsivity-and delinquency, but not between short-term mindsets and cannabis use. These results support the above-mentioned theories and emphasize the importance of investigating the correlates of change in delinquency and cannabis use separately, as divergent findings might emerge. These divergent findings could partially stem from Switzerland's liberal views on cannabis use.

Navigating the Grey Zone: The Impact of Legislative Frameworks in North America and Europe on Adolescent Cannabis Use-A Systematic Review.

This paper aims to systematically review the impact of legislative framework changes in North America and Europe on adolescent cannabis use. It not only seeks to examine the prevalence of adolescent marijuana use following legislative changes but also to identify the driving forces behind fluctuations in use and to address the gaps left by previous studies. A systematic literature review was conducted in selected databases. After screening English-language publications dating from 2013 to 2023 (n = 453 studies), 24 met the inclusion criteria. Articles were considered if they analyzed the impact of legislative changes on adolescent cannabis use in countries across North America and Europe. The overall findings suggest an inconsistency regarding the prevalence of cannabis use among youth and adolescents following policy changes. The effects of modifications in cannabis policies on marijuana consumption are complex and influenced by various factors. These include the details of legislation, societal perspectives, enforcement methods, socioeconomic status, and cultural background. The results of this analysis reveal a nuanced reality. Although research suggests a rise in cannabis use after legalization, there are variations in the outcomes observed. This highlights the significance of considering context and demographics. Moreover, studies shed light on how specific policy changes, such as depenalization, can affect cannabis use.

Hippocampal gray matter volume in young adulthood varies with adolescent alcohol use.

Adolescent substance use is linked with negative future outcomes (e.g., depression, anxiety, substance use disorder). Given that the brain undergoes significant maturation during adolescence, this developmental period may represent a time of particular vulnerability to substance use. Neuroimaging research has largely focused on heavy or binge patterns of substance use; thus, relatively less is known about the neural impact of a broader range of adolescent substance use. Characterizing the neural impact of a broader range of adolescent substance use may inform prevention and treatment efforts. The present study investigated relationships between adolescent substance use trajectories (i.e., alcohol, tobacco, and cannabis) and gray matter volume in young adulthood. Substance use was assessed in 1,594 participants at ages 11, 13, 16, and 19. Following the last assessment, 320 participants completed a single magnetic resonance imaging session to assess brain gray matter volume. Latent growth curve models were used to estimate growth parameters characterizing alcohol, tobacco, and cannabis use trajectories for each participant. These growth parameters (i.e., intercept, linear slope, and quadratic slope) were then used as predictors of gray matter volume. The gray matter volume of the hippocampus was positively associated with age 14 alcohol use (i.e., intercept) but not other trajectories (i.e., progression or acceleration) or substances (tobacco or cannabis). These results provide new insight into the neural impact of distinct adolescent alcohol, tobacco, and cannabis use trajectories, which may help to refine prevention and treatment efforts. (PsycInfo Database Record (c) 2024 APA, all rights reserved).