Early Cannabis Use Research Articles

Systematic review and meta-analysis on the effects of chronic peri-adolescent cannabinoid exposure on schizophrenia-like behaviour in rodents.

The link between cannabis use and schizophrenia is well-established in epidemiological studies, especially among adolescents with early-onset use. However, this association in rodent models is less clear. This meta-analysis examined the effects of adolescent cannabinoid exposure on distinct schizophrenia-like behaviours in rodents and how experimental variations influence outcomes. Following a pre-registered protocol (CRD42022338761), we searched PubMed, Ovid Medline, Embse and APA PsychInfo for English-language original studies until May 2024. We synthesised data from experiments on schizophrenia-like behaviour in rats and mice after repeated peri-pubertal (onset between P23-P45) cannabinoid exposure. Risk of bias was assessed using the SYRCLE's tool. We included 359 experiments from 108 articles across 9 behavioural tests. We found meta-analytic evidence supporting that CB1R agonists, both natural and synthetic, elicited broad schizophrenia-like behavioural alterations, including impaired working memory [g = -0.56; (CI: -0.93, -0.18)], novel object recognition [g = -0.66; (CI: -0.97, -0.35)], novel object location recognition [g = -0.70; (CI: -1.07, -0.33]), social novelty preference [g = -0.52; (CI: -0.93, -0.11)], social motivation [g = -0.21; (CI: -0.42, -0.00)], pre-pulse inhibition [g = -0.43; (CI: -0.76, -0.10)], and sucrose preference [g = -0.87; (CI: -1.46, -0.27)]. By contrast, effects on novelty-induced locomotion were negligible. Subgroup analyses revealed similar effects across sexes and species. Substantial variance in the protocols and moderate-to-high heterogeneity in behavioural outcomes were observed. We found CBD may enhance fear memory recall, but data was limited. This is the first meta-analysis to comprehensively assess the link between cannabinoids and schizophrenia-like behaviours in rodents. Our results support epidemiological links between early cannabis use and schizophrenia-like phenotypes, confirming the utility of animal models. Standardising protocols will optimise models to strengthen reproducibility and comparisons, our work provides a framework for refining rodent models to elucidate biological pathways linking cannabis and schizophrenia.

Cross-substance Effects of Adolescent Exposure to Alcohol Content in Popular Movies on Cannabis Initiation.

Alcohol is the most frequently depicted substance in the media, and adolescent exposure to alcohol in the media predicts alcohol use. There is relatively little research on exposure to cannabis in the media, but exposure to alcohol content may exert cross-substance effects on cannabis use. Given the social and health risks associated with early cannabis use, the present study aims to assess the cross-substance effects of exposure to alcohol media content on age of cannabis initiation. A sample of 830 middle school students (53% female) reported on movie alcohol exposure and cannabis initiation longitudinally until high school completion. Discrete-time survival models examined whether movie alcohol exposure predicted subsequent initiation among students who were cannabis-naïve at baseline, controlling for demographic, social, and behavioral covariates. The interaction between sex and movie alcohol exposure was also explored. One third (33%) of participants reported cannabis initiation with a mean of 5.57 estimated hours (SD = 4.29) of movie alcohol exposure. A 1-hour increase in movie exposure predicted a significant 16% increased probability of cannabis initiation in models adjusted for demographic variables and a significant 14% increase in models adjusted for demographic, behavioral, and social variables. No differences were observed across sex. Greater adolescent exposure to alcohol content in the media was associated with earlier cannabis initiation above and beyond other etiologically relevant demographic, behavioral, and social variables. The influence of cross-substance media exposures warrants further exploration and should be taken into consideration in the development of preventive interventions for youth substance use.

Can drug policies modify cannabis use starting choice? Insights from criminalisation in Italy

A key question in the ongoing drug policy debate is whether legalising cannabis leads to an increase in cannabis use. In Europe although no country has yet moved to legalisation, many have decriminalised personal possession. However, some jurisdictions are still discussing increased sanctions or have further strengthened penalties for the possession of illicit substances in order to deter widespread cannabis use. This is the case in Italy, where a law introduced in 2006 and repealed in 2014 de facto criminalised personal drug possession, and a potential increase in penalties is currently being debated as a policy option. Despite the intense public debate surrounding the legal status of cannabis, limited empirical research has been conducted in Europe to assess the population-level effects of drug policy reforms, mainly due to data availability constraints. In this study, we analyse the effect of criminalisation on the age of onset of cannabis use using an unique dataset that combines seven waves (2001–2017) of the nationally representative Italian Population Survey on Alcohol and other Drugs with relevant socio-economic data. The final dataset comprises 77,650 observations. Leveraging the rare opportunity to examine the effects of a policy that remained in force for a limited period, our empirical investigation employs a Complementary Log-Log model to analyse the starting rate, that is, the transition rate from non-use to use. To do so, we use self-reported data on the age of first cannabis use. Our results suggest that the implementation of stricter punishments has a significant effect in reducing the likelihood of early cannabis use initiation. The observed impact of criminalisation is limited in younger ages and diminished as adulthood approaches. This paper also discusses other considerations related to the social costs of criminalisation, which should also be taken into account in the ongoing policy debate.

Risky cannabis use is associated with varying modes of cannabis consumption: Gender differences among Canadian high school students

BackgroundOur objective was to explore associations between indicators of more risky cannabis use (i.e., solitary use, frequent use, and younger age of initiation) and different modes of cannabis use (i.e., smoking, vaping and/or edibles). MethodsData were gathered from a large sample of Canadian youth in Alberta, British Columbia, Ontario, and Quebec who participated in Year 8 (2019–20) of the COMPASS study, and who reported using cannabis in the past year (n = 4,763). Generalized estimating equations were used to examine associations between risky cannabis use and modes of cannabis use, stratified by gender. ResultsOverall, 38% of students reported using multiple modes of cannabis use. Consistent among both males and females, students who used cannabis alone (35%) and at a higher frequency (55%) were more likely to use multiple modes than smoking only. Among females, those who used cannabis alone were more likely to report using edibles only compared to smoking only (aOR=2.27, 95%CI=1.29–3.98). Earlier cannabis use initiation was associated with lower likelihood of vaping cannabis only among males (aOR=0.25; 95%CI = 0.12–0.51), and lower likelihood of using edibles only among females (aOR=0.35; 95%CI = 0.13–0.95), than by smoking only. ConclusionsOur findings suggest that multiple modes of use may be an important indicator or risky cannabis use among youth, given associations with frequency, solitary use, and age of onset.

Parent and Adolescent Reports of Parental Monitoring and Sources of Parental Knowledge are Linked to Cannabis Use and Symptom Development in Adolescents.

Greater discrepancies between parent and adolescent reports of parenting behaviors are associated with poorer adolescent functioning. The present research aims to build from the existing literature by examining unique parent and adolescent perceptions of parental monitoring and distinct sources of parental knowledge (i.e, parental solicitation, parental control, child disclosure) and their association with adolescent cannabis and alcohol use and disorder symptoms using cross-sectional data. Parent-adolescent dyads (N = 132) were recruited from the community and the family court system. Adolescents were ages 12 to 18 (40.2% female; 68.2% White, 18.2% Hispanic). Parents and adolescents completed a questionnaire assessing the four domains of parenting behaviors. Adolescents' substance-use behaviors and related disorder symptoms were assessed via adolescent self-report and semi-structured interviews. Parental ratings of distinct parenting behaviors were higher (more favorable) than their child's reports, as shown in prior studies. Parent-reported parenting behaviors were uniquely related to cannabis use, over and above adolescent reports and the adolescent's age. With regard to report discrepancies, interactive effects of parent and adolescent perceptions of parental control were not statistically significant in our analysis after correcting for multiple tests. While most research relating parental monitoring to adolescent cannabis use relies solely on adolescent perceptions, our study suggests a unique role of parent perceptions for cannabis use and disorder symptoms, respectively. Findings support the importance of considering unique parent and adolescent perceptions of what parents know, as well as how they know it, to understand early cannabis use and problem development.

Adult Psychiatric, Substance, and Functional Outcomes of Different Definitions of Early Cannabis Use.

Research on associations of early cannabis use with adult functioning reports mixed findings. This may be due, in part, to wide variations in the definitions of early cannabis use. This study aims to compare associations of 4 commonly used definitions of early cannabis use-related to timing, dose, duration, and associated symptoms-with adult outcomes. Analyses were based on a 20+-year longitudinal, community-representative study of 1,420 participants. Between ages 9 and 21 years (8,806 observations), participants were assessed for cannabis use and DSM-5 cannabis use disorder. In early adulthood (ages 24-26 and 30; 2,424 observations of 1,266 subjects), participants were also assessed for psychiatric, substance use, and functional outcomes. All definitions of early use were associated with multiple adult outcomes in models that adjusted for sex and race/ethnicity. In models that also adjusted for childhood psychiatric problems and family adversities, only daily use and a persistent developmental subtype (defined as daily/problematic use that began in adolescence and continued into early adulthood) were associated with later substance use/disorders, poorer functional outcomes, and derailments in the transition to adulthood. Daily, continued-over-time cannabis use beginning on adolescence was most problematic for a range of adult outcomes. Cessation of early use did not fully eliminate later risks; but was associated with fewer negative outcomes, with weaker effect sizes.

Premorbid characteristics of patients with DSM-IV psychotic disorders

IntroductionPsychotic disorder not otherwise specified (PNOS) is considered part of the psychosis spectrum, together with schizophrenia spectrum disorders (SSD) and psychotic bipolar spectrum disorders (PBD). The atypical clinical presentations of PNOS conditions may lead to uncertainty regarding treatment choices and expected outcomes. PNOS is understudied, and little is known about patients' premorbid characteristics including premorbid adjustment, prevalence of early cannabis use and childhood trauma. Knowledge about early illness phases can increase our understanding of this diagnostic group. MethodsWe included 1099 participants from the Norwegian TOP-study; 688 with narrow SSD diagnoses (schizophrenia, schizoaffective disorder, schizophreniform disorder), 274 with PBD (psychotic bipolar 1 and bipolar NOS) and 137 with PNOS diagnosed with the SCID-I for DSM-IV. Participants were assessed with the Premorbid Adjustment Scale (PAS) divided into the areas of premorbid academic and social functioning. We obtained information on age at first exposure to cannabis and use of cannabis before the age of 16. The participants also provided information regarding early traumatic experiences using the Childhood Trauma Questionnaire (CTQ). ResultsParticipants with PNOS and SSD had poorer premorbid academic functioning than those with PBD (F2, 1029 = 7.81, p < 0.001, pη2 = 0.015). Premorbid social adjustment was significantly worse in the SSD group compared to the PBD group (F2, 1024 = 3.10, p = 0.045, pη2 = 0.006), with PNOS in the middle position. Significantly more of the participants with PNOS (17.5%) and SSD (11.5%) used cannabis before the age of 16 compared with PBD (5.3%, Wald χ2 = 6.86, p = 0.03). There were no significant differences between the three groups regarding mean CTQ scores or in the proportion of participants who had experienced at least one type of childhood adversity. ConclusionsParticipants with PNOS appear as more similar to participants with SSD than to those with PBD regarding early premorbid adjustment and early cannabis use. The results indicate that many conditions classified as PNOS have functional impairments and problematic substance use from an early age. The prevalence of childhood adversities are high in all three groups.

Psychometric properties of CAST for early detection of problematic cannabis use in Spanish adolescents

The high prevalence rates of cannabis use in adolescents and its early onset constitutes a major public health problem, raising the need for its early detection. The availability of validated tools to analyze early cannabis use is essential to detect problematic use at an early age. The Cannabis Abuse Screening Test (CAST) (Legleye et al., 2007) is widely applied in Europe; however, the CAST cut-off scores vary according to the setting, the screening objective, and the correction version (CAST-f or CAST-b), creating therefore confusion in its application. Moreover, the psychometric properties of the CAST as a tool for detecting problematic cannabis use are understudied. To fill this gap, such psychometric properties have been analyzed in a sample of Spanish adolescents while using different cut-off scores for CAST-f and CAST-b. Based on our findings, the optimal cut-off scores are 2 points for CAST-b and 4 points for CAST-f. The internal reliability of CAST-f (α = 0.83) and CAST-b (KR-20 = 0.80) are satisfactory. Factorial analysis suggested the assumption of a one-dimension model. The CAST seems to be a valid and reliable tool for early screening of problematic cannabis use in Spanish adolescents.

Evolution of impulsivity levels in relation to early cannabis use in violent patients in the early phase of psychosis.

Prevention of violent behaviors (VB) in the early phase of psychosis (EPP) is a real challenge. Impulsivity was shown to be strongly related to VB, and different evolutions of impulsivity were noticed along treatments. One possible variable involved in the relationship between VB and the evolution of impulsivity is cannabis use (CU). The high prevalence of CU in EPP and its relationship with VB led us to investigate: 1/the impact of CU and 2/the impact of early CU on the evolution of impulsivity levels during a 3-year program, in violent and non-violent EPP patients. 178 non-violent and 62 violent patients (VPs) were followed-up over a 3 year period. Age of onset of CU was assessed at program entry and impulsivity was assessed seven times during the program. The evolution of impulsivity level during the program, as a function of the violent and non-violent groups of patients and CU precocity were analyzed with linear mixed-effects models. Over the treatment period, impulsivity level did not evolve as a function of the interaction between group and CU (coef. = 0.02, p = 0.425). However, when including precocity of CU, impulsivity was shown to increase significantly only in VPs who start consuming before 15 years of age (coef. = 0.06, p = 0.008). The precocity of CU in VPs seems to be a key variable of the negative evolution of impulsivity during follow-up and should be closely monitored in EPP patients entering care since they have a higher risk of showing VB.

Cannabis smoking and glaucoma in the UK Biobank cohort

Cigarette smoking is a well-known risk factor for primary open-angle glaucoma (POAG). Tobacco smoke contains a variety of chemicals, including nicotine, free radicals, and carbon monoxide, all of which can play a role in the development of POAG. Cannabis smoke, like tobacco smoke, contains a comparable variety of carcinogenic and toxic compounds. In the present study, we analyzed UK Biobank data to determine whether smoking cannabis, like cigarettes, might be related to POAG. Our analysis included all subjects with glaucoma and cannabis smoking information. Data processing was performed on Minerva, a Linux mainframe with Centos 7.6, at the Icahn School of Medicine at Mount Sinai. We used the UK Biobank Data Parser (ukbb parser), a python-based package that allows easy interfacing with the large UK Biobank dataset. Statistical analysis was performed with SPSS 25 and R. Subjects who used cannabis 100 times or more were significantly younger (10years) when they developed glaucoma than subjects who never used cannabis. The effects of age (P<0.001) and cigarettes (P=0.014) on POAG incidence were significant, but the effect of cannabis use was not (P=0.662). The effect of cannabis use on age at glaucoma diagnosis was significant and unrelated to the effects on intraocular pressure or cigarette pack-years smoked. Analysis of intraocular pressure showed that mean pressures of subjects who used cannabis 11-100 times were significantly lower than those who took no cannabis. Inhaling cannabis smoke is injurious to the eye, but in the case of glaucoma the manifestations are different from those of inhaled tobacco smoke. Cannabis reduces intraocular pressure but accelerates glaucoma development. Cannabis does not increase risk of glaucoma. Cigarette smoking increases risk of glaucoma and significantly accelerates glaucoma development. Apparently, early use of cannabis leads to the earlier development of glaucoma.

Early Age of Cannabis Initiation and Its Association With Suicidal Behaviors.

Background:Suicide rates in the U.S. have continued to rise over the last 2 decades. The increased availability and broader legalization of cannabis is a public health concern, particularly among adolescents. The objective of this study was to examine the association between the age of cannabis initiation and lifetime suicidal ideations and attempts in a sample of adults aged 18 or older.Methods:Data are from the Collaborative Psychiatric Epidemiology Surveys (CPES), 2001 to 2003 (N = 15 238). The primary objective of the CPES was to collect data about the prevalence of mental disorders, impairments associated with these disorders, and their treatment patterns from representative samples of majority and minority adult populations in the U.S. Logistic regression analyses were conducted to test the association between cannabis initiation age (early ⩽14 years old; later >14 years old) and outcomes of lifetime suicide ideation and attempts. Cigarette use, cannabis use, gender, income, race, education, and age were controlled for the analyses.Results:Overall, 12.5% of participants reported suicide ideation, while 4.2% reported attempt. Early cannabis use was associated with a higher risk of suicide ideation (AOR = 3.32, 95% CI [2.75, 3.80]) than later cannabis use (AOR = 2.15, 95% CI [1.92, 2.39]). Early cannabis use was associated with a higher risk of suicide attempt (AOR = 4.38, 95% CI [3.48, 5.52]) than later cannabis use (AOR = 2.56, 95% CI [2.14, 3.06]). Wald chi-squared tests revealed significant differences between the early and late initiation for both ideation (χ2 = 26.99; P < .001) and attempts (χ2 = 26.02; P < .001).Conclusions:Significant associations were found between early initiation of cannabis and suicide behaviors. As suicide rates continue to rise, it is recommended that clinicians, treatment providers, and other professionals consider the use of cannabis at an early age as a risk for subsequent suicide behaviors.

Prenatal cocaine exposure, early cannabis use, and risky sexual behavior at age 25

BackgroundPrior research on prenatal cocaine exposure (PCE) indicates that exposed children experience behavioral dysregulation resulting in risky adolescent behavior including earlier initiation of cannabis use and sexual intercourse. The goal of this study was to examine the long-term effects of PCE on adult sexual behavior. MethodsThis is a prospective cohort study of the association between PCE and risky adult sexual behavior and sexually transmitted infections (STIs) in 202 young adults (mean age = 27, SD = 0.98 years). The sample was 55% female, 46% White, and 54% Black. Data from the prenatal, childhood, and adolescent phases of the study were used to delineate pathways from PCE to adult sexual behavior. ResultsThe most common risky sexual behavior was having sex while drunk or high (63%). One-third of the sample reported that they “almost always” had sex while drunk or high. We found evidence for an indirect pathway from PCE to adult sex while drunk or high via early cannabis initiation. There were no other effects of PCE on adult risky sexual behavior or on risk for STIs, after controlling for sex assigned at birth, race, age at sexual initiation, and family history of drug and alcohol problems. ConclusionsAlthough PCE has been associated with earlier initiation of sex in prior studies, PCE was not directly associated with risky adult sex or history of STI. Exposed individuals were at greater risk of sex under the influence of alcohol or drugs via earlier initiation of cannabis use during adolescence.

Adolescent exposure to cannabis marketing following recreational cannabis legalization in Canada: A pilot study using ecological momentary assessment

ObjectiveThe goal of this pilot study was to assess the feasibility of a 9-day, smartphone-based ecological momentary assessment (EMA) protocol for tracking the frequency of Canadian adolescents’ exposures to cannabis marketing, their reactions to such exposures, and the context in which exposures occur in the real-world and in real-time. MethodParticipants were n = 18 adolescents between the ages of 14 and 18 years of age. They used an EMA application to capture and describe cannabis marketing exposures through photographs and brief questionnaires assessing marketing channel and context. Participants also rated their reactions to each exposure in real-time. ResultsResults showed that participants were generally compliant with the protocol. Participants recorded 40 total exposures to cannabis marketing, representing an average of 2.2 (SD 2.3) exposures per participant during the 9-day study. Exposures tended to occur in the afternoon (45.0%) or evening (37.5%), and while participants were at home (70%) and alone (52.5%). Most exposures occurred through promotion by public figures (27.5%) or explicitly marked internet ads (27.5%). ConclusionThis is the first study to demonstrate the feasibility and utility of EMA to capture adolescent exposures to cannabis marketing as it occurs in participants’ natural environments. Our research offers an early look at the predictable wave of cannabis advertising targeting youth and a promising approach for studying its impacts in a post-legalization context, as well as a strategy for assessing policies, such as advertising restrictions, intending to mitigate the harms of early cannabis use among youth.

Alcohol trajectories and subsequent risk for opioid misuse in a cohort of urban adolescents

Background: The opioid epidemic is a public health emergency in the US. Alcohol is the most widely used addictive substance among all age groups; however, the contribution of different alcohol use trajectories throughout adolescence and young adulthood to the development of opioid misuse in young adulthood among urban minority youth has not been investigated. Methods: Data are from a study of 580 youth (85% African American, 67% low SES) residing in Baltimore City followed from ages 6–26. Alcohol trajectories were identified between ages 14 and 26 using group-based trajectory modeling. Opioid misuse was defined as using opioid painkillers without a prescription or using heroin between ages 19 and 26. Opioid misuse outcomes were also investigated separately. Logistic regression examined associations of alcohol trajectories with opioid misuse in young adulthood adjusting for socio-demographics, early use of tobacco and cannabis, neighborhood, and peer factors. Results: Six alcohol use trajectories were identified: Young adult increasing (21.4%), adult increasing (19.1%), abstaining (19.1%), experimenting (15.3%), adolescent increasing (14.8%), and adolescent limited (10.2%). In models fully adjusted for covariates, relative to the abstaining trajectory, the adolescent increasing trajectory was associated with an elevated risk of opioid misuse (aOR = 3.3, 95%CI = 1.4, 7.8) and prescription opioid misuse (aOR = 3.9, 95%CI = 1.4, 10.8) in young adulthood. Conclusions: Escalating alcohol use in adolescence and young adulthood is associated with an elevated risk of opioid misuse in young adulthood in a cohort of predominantly African American and socio-economically disadvantaged young people. Tailored interventions should target high levels of alcohol use during these developmental periods to reduce risk for opioid misuse among disadvantaged youth.

Cannabis Use Among Patients With Psychotic Disorders.

Amidst a rapidly changing legal landscape, cannabis use in the United States has become increasingly common in the past several years. There is strong evidence to suggest that chronic and early cannabis use increases the risk of developing a psychotic disorder, and there is at least moderate evidence that suggests ongoing cannabis use among individuals with a psychotic disorder worsens clinical outcomes (eg, decreased psychiatric medication adherence, more frequent psychiatric hospitalizations). In this Review Article, we provide a focused, clinically oriented overview of the epidemiology and characteristics of cannabis use among individuals with first-episode psychosis; evaluation of cannabis use; and treatment modalities, focusing on behavioral interventions suitable for outpatient primary care settings. We discuss the limited data supporting pharmacologic interventions for cannabis use disorder, specifically among individuals with first-episode psychosis, and the unique potential of cannabidiol to serve as a harm-reduction strategy for individuals who are not able or willing to achieve abstinence for cannabis.

Latent triple trajectories of substance use as predictors for the onset of antisocial personality disorder among urban African American and Puerto Rican adults: A 22-year longitudinal study

Background Antisocial personality disorder (ASPD) incurs a high cost to society due to the high risk of violent and nonviolent offenses associated with this personality disorder, thus making the examination of the etiology and the onset of ASPD an important public health concern. Method: The present study consisted of five waves of data collection of the Harlem Longitudinal Development Study (N = 674). In the Cox proportional hazard model, latent multiple substance use trajectories from mid-adolescence to emerging adulthood (mean age 14 to mean age 24) were used as a predictor for the onset of ASPD during emerging adulthood to the mid-thirties (mean age 24 to mean age 36). The control variables were gender, ethnicity, problem behaviors, and victimization. Results: In the multiple Cox proportional hazard model, the high (HR = 2.74, p < 0.001) and the increasing frequency of (HR = 2.55, p < 0.001) use on alcohol, cigarette, and cannabis latent trajectory groups were associated with an increased hazard of ASPD onset as compared with the no or low frequency of use on alcohol, cigarette, and cannabis latent trajectory group after controlling for demographic factors and earlier problem behaviors as well as victimization. Conclusions: The implications of this study for the prediction of adult ASPD onset time may focus on the early use of alcohol, cigarette, and cannabis from mid adolescence to emerging adulthood.

Cannabis Consumption Onset and Addiction: Data from the Second Brazilian Drugs and Alcohol Survey (BNADS)

ABSTRACT The objective of this study was to provide rates of cannabis use and dependence and risk factors, proposing a conditional path model for cannabis addiction. A subsample of adult participants from a Brazilian household survey was analyzed to estimate cannabis dependence. Estimation of prevalence rates and association between dependence and age of cannabis use initiation were performed. The conditional model was applied to investigate the mediation of depressive symptoms and alcohol consumption in the association of early cannabis use and dependence. Lifetime and last year cannabis use were 6.47% and 2.81%, respectively. Moderate and severe cannabis dependence were 0.74% and 0.18% in the population, and 26.47% and 6.38% among last year’s cannabis users. A Parallel Multiple Mediator Model revealed strong association between cannabis use initiation age and dependence, when depressive symptoms or alcohol consumption mediate this association. The proportion of cannabis users displaying dependence symptoms is elevated and it is associated with the age of cannabis use initiation. The results show the importance of primary prevention interventions, prioritizing the delay of cannabis and alcohol experimentation. Our findings can enrich the debate on drugs policies and legislation, reinforcing the need for stronger restrictions of adolescent drug access and ensuring its enforcement.

Association between age of cannabis initiation and gray matter covariance networks in recent onset psychosis

Cannabis use during adolescence is associated with an increased risk of developing psychosis. According to a current hypothesis, this results from detrimental effects of early cannabis use on brain maturation during this vulnerable period. However, studies investigating the interaction between early cannabis use and brain structural alterations hitherto reported inconclusive findings. We investigated effects of age of cannabis initiation on psychosis using data from the multicentric Personalized Prognostic Tools for Early Psychosis Management (PRONIA) and the Cannabis Induced Psychosis (CIP) studies, yielding a total sample of 102 clinically-relevant cannabis users with recent onset psychosis. GM covariance underlies shared maturational processes. Therefore, we performed source-based morphometry analysis with spatial constraints on structural brain networks showing significant alterations in schizophrenia in a previous multisite study, thus testing associations of these networks with the age of cannabis initiation and with confounding factors. Earlier cannabis initiation was associated with more severe positive symptoms in our cohort. Greater gray matter volume (GMV) in the previously identified cerebellar schizophrenia-related network had a significant association with early cannabis use, independent of several possibly confounding factors. Moreover, GMV in the cerebellar network was associated with lower volume in another network previously associated with schizophrenia, comprising the insula, superior temporal, and inferior frontal gyrus. These findings are in line with previous investigations in healthy cannabis users, and suggest that early initiation of cannabis perturbs the developmental trajectory of certain structural brain networks in a manner imparting risk for psychosis later in life.

Associations of childhood sociability and responsibility with cannabis use trajectories during adolescence: results from a prospective population-based birth cohort study.

This study aims to identify distinct trajectories of cannabis use during adolescence and examine whether Sociability (ability to relate to others) and Responsibility (ability to integrate a community setting) during childhood are associated with these trajectories, accounting for individual and familial confounders. Population-based cohort study (1998-2019): 1511 children from the Quebec Longitudinal Study of Child Development were followed between ages 5months and 19years. We identified developmental trajectories of adolescent cannabis use (assessed biyearly between ages 12 and 19years) using a group-based trajectory model. We performed multinomial regression analyses to estimate the association between childhood Sociability and Responsibility assessed yearly between ages 6 and 12years, and cannabis use trajectories. At 19years, 62.8% (807/1286) of adolescents had used cannabis at least once in their lifetime, 44.2% had used at least once in the past 12months (504/1140), and 6.8% were reporting daily use (77/1140). We identified three cannabis use trajectories:nonusers(n = 577, 38.2%), late users (n = 690, 45.7%; mean age of initiation: 16.2 ± 1.6), and early users (n = 244, 16.2%; mean age of initiation: 14.1 ± 1.3). Compared with Nonusers, children with low Sociability had a lower risk for late (OR, 0.43; 95 CI 0.27; 0.68) and early (OR, 0.22; 95 CI 0.12; 0.41) cannabis use. Children with low Responsibility were at higher risk of being Early users (OR, 2.23; 95 CI 1.13; 4.37) but not Late users (OR, 1.20; 95 CI 0.71; 2.03). Understanding the multiple dimensions of social skills and their association with cannabis use trajectories may help improve the effectiveness of evidence-based prevention strategies.

Are Schizophrenic disorders with or without early cannabis use neurobiologically distinct disease entities? A meta-analysis of magnetic resonance imaging studies

Cannabis use is considered an important risk factor for the development of psychotic illness and is associated with worse outcomes of the disorder. This study aimed to determine through a meta-analytic approach whether patients at the onset of schizophrenia with comorbid cannabis use (SCH CU+) show a different pattern of brain abnormalities as compared to patients with no comorbid cannabis use (SCH CU-). Ten Magnetic Resonance Imaging (MRI) studies were identified as suitable for analysis leading to the inclusion of n= 465 patients with schizophrenia (n= 227 SCH CU+ and n= 238 SCH CU-) and n= 366 healthy controls. Compared to healthy controls, both SCH CU+ and SCH CU- patients showed reduction of whole brain, total grey matter and hippocampal volumes. The direct comparison of SCH CU+ and SCH CU- patients, including up to 5 independent studies, did not demonstrate significant differences of brain volumes between the two groups even though total and regional grey matter volume deficits were more prominent in SCH CU+ patients. The available literature data indicate that, essentially, there is an overlap of brain abnormalities in SCH CU+ and SCH CU- patients at the onset of schizophrenia. The common vs specific trajectories of brain pathomorphology in SCH CU+ and SCH CU- patients are discussed.