[pt] O uso de cannabis é um problema de saúde pública crescente, associado a diversos desfechos negativos. A identificação de fatores de risco é relevante para a prevenção, pois nem sempre tratamentos são eficazes. O abuso sexual infantil é considerado um forte preditor de uso e transtorno por uso de cannabis (TUC). Com a expansão da internet a violência sexual assumiu novos formatos, fazendo surgir um fenômeno contemporâneo denominado vitimização sexual on-line (VSO). Esta dissertação se dedicou ao aprofundamento do tema e realizou uma revisão narrativa com o objetivo de sintetizar o conceito de VSO e seus paralelos com abuso sexual off-line. Além disso, foi investigado exploratoriamentea VSO na infância e adolescência e suas associações com o uso de cannabis e TUC. Análises de regressão investigaram o efeito preditivo de VSO no uso de cannabis ao menos uma vez na vida e na idade do primeiro uso de cannabis. Mais de 70 por cento da amostra relatou ter sofrido VSO na infância e adolescência. Mulheres apresentaram quase o dobro de prevalência que os homens, com médias mais elevadas nas subescalas de insistência e ameaça. Minorias sexuais foram mais prevalentes que heterossexuais em todas as subescalas. A VSO foi capaz de prever significativamente o uso de cannabis pelo menos uma vez na vida e a idade do primeiro uso, mas somente a subescala de disseminação. Os resultados sugerem que VSO na infância e na adolescência é um fenômeno com alta prevalência, que pode estar associada ao uso de cannabis. Crianças e adolescentes merecem atenção especial porque utilizam a internet com maior freqüência, ficando expostos a riscos. Dessa maneira, é necessário pensar estratégias para prevenção de ocorrência de VSO e seusefeitos adversos. / [en] Cannabis use is a growing public health problem, associated with a variety of negative outcomes. The identification of risk factors is relevant for prevention, as treatments are not always effective. Child sexual abuse is considered a strong predictor of cannabis use and cannabis use disorder (CUD). With the expansion of the internet, sexual violence took on new formats, giving rise to a contemporary phenomenon called online sexual victimization (OSV). This dissertation was dedicated to deepening the theme and carried out a narrative review with the objective of synthesizing the concept of OSV and its parallels with offline sexual abuse. In addition, we exploratory investigated OSV in childhood and adolescence and its associations with cannabis use and CUD. Regression analyzes investigated the predictive effect of OSV on lifetime cannabis use and age of first cannabis use. More than 70 percent ofthe sample reported having suffered OSV in childhood and adolescence. Women had almost twice the prevalence of men, with higher means in the insistence and threat subescales. Sexual minorities were more prevalent than heterosexualin allsubscales. The OSV was able to significantly predict lifetime cannabis use and age atfirst use, but only the spread subscale. The results suggest that OSV in childhood and adolescence is a highly prevalent phenomenon that maybe associated with cannabis use. Children and teenagers deserv especial attention because they use the internet more frequently and are exposed to risks. Thus, it is necessary to think about strategies to prevent the occurence of OSV and its adverse effects.

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Background: A younger age at onset of use of a specific substance is a well-documented risk-factor for a substance use disorder (SUD) related to that specific substance. However, the cross-substance relationship between a younger age at onset of alcohol use (AU) and nicotine use (NU) and the risk of cannabis use disorders (CUD) in adolescence and early adulthood remains unclear. Aims: To identify the sequence of and latency between initial AU/NU and initial cannabis use (CU). To investigate whether younger age at AU- and NU-onset is associated with any and earlier CU-onset and a higher risk of transition from first CU to CUD, taking into account externalizing disorders (ED) and parental substance use disorders as putative influential factors. Methods: Prospective-longitudinal community study with N = 3021 subjects (baseline age 14–24) and up to four assessment waves over up to ten years with additional direct parental and family history information. Substance use and CUD were assessed with the DSM-IV/M-CIDI. Results: Most subjects with CU reported AU (99%) and NU (94%). Among users of both substances, 93% reported AU prior to CU (87% for NU). After adjustment for ED and parental substance use disorders younger age at AU-onset was associated with any CU. Younger age at NU-onset was associated with earlier CU initiation. Younger age at AU- and NU-onset was not associated with a higher risk of CUD. Conclusions: The cross-substance relevance of younger age at first AU and NU for the risk of CUD is limited to early CU involvement.

Le cannabis est la substance illicite la plus consommée à l’adolescence et ce, mondialement. Nous savons qu’un usage problématique de cannabis est susceptible d’entraîner une multitude de conséquences sur les plans physiques, psychologiques, sociaux et économiques. Or, les consommateurs constituent un groupe au profil hétérogène et n’expérimenteront pas tous des problèmes significatifs reliés à cet usage. Il s’avère donc important d’identifier les usagers à risque élevé de conséquences et de spécifier la nature de ces problèmes afin d’intervenir de façon efficace auprès de cette clientèle. Pourtant, bien que la littérature scientifique soulève l’idée que certains types de consommateurs présentent davantage de risques, l’état des connaissances ne révèle que peu d’informations de nature empirique qui permettraient de distinguer des autres usagers les profils d’adolescents davantage à risque. À cet effet, les typologies disponibles à ce jour sont généralement théoriques ou limitées aux études cliniques, font référence à des problèmes particuliers ou se basent sur des indicateurs spécifiques de la consommation tels que la fréquence d’usage. De plus, aucune étude jusqu’à maintenant n’est en mesure de nous pister quant aux types de problèmes associés plus spécifiquement à certains profils de consommation ni de préciser quels profils sont davantage représentés pour des conséquences données. Cette étude est basée sur les classes latentes de consommation découvertes dans l’étude de Fallu, Brière et Janosz (2014) à partir de plusieurs caractéristiques de consommation et comparées sur plusieurs prédicteurs et problèmes associés à la consommation. Son échantillon est constitué de 1618 élèves consommateurs de cannabis en secondaire 4. Cette étude examine quels sont les problèmes attribués et non-attribués les plus fréquents pour chacune des classes. Elle examine également quelles sont les classes les plus représentées pour différents problèmes attribués et non-attribués. Enfin, elle compare les résultats obtenus pour les problèmes attribués et non-attribués. La stratégie analytique employée a consisté à conduire des analyses descriptives, des analyses de Chi carrés ainsi que des analyses de variance univariée, parfois suivies d’une analyse post-hoc. Les résultats ont démontré que la classe d’appartenance peut prédire la survenue des différents problèmes que rencontrent les jeunes consommateurs, que certaines classes sont plus représentées pour certains problèmes et que les adolescents aux profils les plus lourds sont à risque de sous-estimer certains problèmes liés à leur consommation. L’une des principales découvertes concerne les deux classes précoces. Il semble que la classe des consommateurs modérés précoces présente un profil de problèmes davantage intériorisé et la classe des polyconsommateurs lourds précoces, davantage extériorisé. Les implications de ces résultats sont finalement discutées. / Cannabis is the most widely used illicit substance among adolescents worldwide. We know that cannabis misuse is likely to cause a variety of effects at physical, psychological, social and economic levels. However, consumers are a heterogeneous group and not all will experience significant problems associated with such use. It is therefore important to identify high-risk users and to specify the nature of these problems in order to intervene effectively with this clientele. Yet, although the scientific literature raises the idea that certain types of consumers are at higher risk, the current state of knowledge reveals little empirical information that would distinguish adolescents with higher risk profiles. To this end, the typologies available today are generally limited to theoretical or clinical studies, refer to specific problems, or are based on specific consumption indicators such as frequency of use. Furthermore, no study has yet been able to reveal the types of problems associated specifically with certain consumer profiles or to specify which profiles are more prone to various consequences. The present study is based on a latent class consumption model developed from several consumer characteristics found in the study by Fallu, Briere and Janosz (2014). They were compared with several predictors and problems associated with the consumption. The sample comes from within the context of evaluation of the New Approaches New Solutions (NANS) dropout prevention program, and consists of 1618 students who used cannabis in 10th grade. The subjects were annually evaluated from the 7th grade until the 11th. This study examines which attributed and non-attributed problems are most common for each class. It also examines which classes are most frequently assigned to different attributed and non-attributed problems. Finally, it compares the results obtained for the attributed and non-attributed problems. The analytical strategy used was to conduct descriptive analysis, chi-square analysis and univariate analysis of variance (ANOVA), sometimes followed by post-hoc tests when relevant. The results show that the class can predict the occurrence of various problems that young people face, that some classes are more represented for some problems, and that teenagers with heavier profiles are at risk of underestimating certain problems associated with their consumption. One of the main findings regarding the two early classes. It seems that early-moderate use students have a more internalized problems profile and those with early-heavy and polydrug use, a more externalized problems profile. Finally, the implications of these results are discussed.

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.

Background: A younger age at onset of use of a specific substance is a well-documented risk-factor for a substance use disorder (SUD) related to that specific substance. However, the cross-substance relationship between a younger age at onset of alcohol use (AU) and nicotine use (NU) and the risk of cannabis use disorders (CUD) in adolescence and early adulthood remains unclear. Aims: To identify the sequence of and latency between initial AU/NU and initial cannabis use (CU). To investigate whether younger age at AU- and NU-onset is associated with any and earlier CU-onset and a higher risk of transition from first CU to CUD, taking into account externalizing disorders (ED) and parental substance use disorders as putative influential factors. Methods: Prospective-longitudinal community study with N = 3021 subjects (baseline age 14–24) and up to four assessment waves over up to ten years with additional direct parental and family history information. Substance use and CUD were assessed with the DSM-IV/M-CIDI. Results: Most subjects with CU reported AU (99%) and NU (94%). Among users of both substances, 93% reported AU prior to CU (87% for NU). After adjustment for ED and parental substance use disorders younger age at AU-onset was associated with any CU. Younger age at NU-onset was associated with earlier CU initiation. Younger age at AU- and NU-onset was not associated with a higher risk of CUD. Conclusions: The cross-substance relevance of younger age at first AU and NU for the risk of CUD is limited to early CU involvement.

Road traffic crashes are a serious public health problem worldwide, and human factors are the most prominent factor of accidents, affecting mostly the young adults. Past studies found that both gender and personality traits such as impulsivity are associated with risky driving, however, the interaction of these predictors is rarely addressed in the literature. To bridge the gap, the present study explores how a specific facet of impulsivity interacts with our hypothesized moderator, gender identification, leads to drug driving using a moderator analysis. We recruited participants from 17 to 35 years old possessing a valid drivers' licence via Facebook advertising. They were invited to complete a questionnaire on their socio-demographic characteristics, cannabis consumption habits and impulsivity scores. A moderator analysis is conducted to disentangle the relationship between sensation seeking, gender and driving after cannabis consumption using SPSS Process. The proposed model contains sensation seeking as an exogenous variable directly associated with driving after cannabis use, and this relationship is moderated by gender identification. The current study provides evidence that sensation seeking and gender identification are not only associated with DACU but also interact to affect driving behaviour. Implications of the study are discussed. / Les accidents routiers constituent de graves problèmes de santé publique dans le monde et les facteurs humains sont connus pour être le principal facteur d'accidents, impliquant principalement les jeunes adultes. Des études antérieures ont démontré que le genre ainsi que des facteurs liés à la personnalité tels que l'impulsivité sont associés à la conduite après consommation récente de cannabis, cependant, l'interaction de ces prédicteurs est rarement abordée dans la littérature. Pour cette raison, cette étude vise à explorer le processus par lequel une facette spécifique de l'impulsivité interagit avec le genre ou le sexe pour modérer la probabilité de prendre le volant après avoir consommé du cannabis. Des participants de 17 à 35 ans possédant un permis de conduire valide ont été recrutés à partir de Facebook par le biais d’annonces payantes. Ils étaient invités à remplir un questionnaire portant sur leur caractéristique socio-démographique, leur habitude de consommation de cannabis, ainsi que sur les composantes de l'impulsivité. Une analyse de modération a été effectuée pour clarifier la relation entre la recherche de sensations, le genre et la conduite d’automobile à l'aide du SPSS PROCESS. Le modèle proposé inclut la recherche de sensations comme variable exogène directement associée à la conduite après la consommation du cannabis, et cette relation est modérée par le genre ressenti. Effectivement, le genre ressenti des participants semble être une variable modératrice de l’association entre la recherche de sensation et la prise de volant après avoir consommé du cannabis. Les implications de ces résultats seront discutées.

The association between extent of chronic cannabis use (CCU-extent) and cognitive impairment among adolescents has been the subject of controversial debate. Linking DNA methylation to CCU-extent could help to understand cannabis associated changes in cognitive performance. We analyzed cognitive task performances, CpG methylation in peripheral whole-blood samples and self-reported past-year CCU-extent of n = 18 adolescents (n = 9 psychiatric outpatients with chronic cannabis use (CCU), n = 9 without) who were matched for age, gender and psychiatric disorders. Patients with CCU were at least 24 h abstinent when cognitive tasks were performed. A Principal Component Analysis (PCA) was carried out to identify group differences in whole genome DNA methylation. Mediation analyses were performed between CCU-extent associated CpG sites and CCU-extent associated variables of cognitive tasks. PCA results indicated large differences in whole genome DNA methylation levels between the groups that did not reach statistical significance. Six CpG sites revealed reduced methylation associated with CCU-extent. Furthermore, CCU-extent was associated with lower scores in verbal learning. All six CpG sites mediated the effects between CCU-extent and verbal learning free recall. Our results indicate that CCU is associated with certain patterns in the methylome. Furthermore, CCU-extent associated impairments in memory function are mediated via differential methylation of the six CCU-associated CpG sits. Six identified CpG are located in genes previously described in the context of neurodegeneration, hippocampus-dependent learning and neurogenesis. However, these results have to be carefully interpreted due to a small sample size. Replication studies are warranted.

The Brisbane Longitudinal Twin Study (BLTS) was being conducted in Australia and was funded by the US National Institute on Drug Abuse (NIDA). Adolescent twins were sampled as a part of this study and surveyed about their substance use as part of the Pathways to Cannabis Use, Abuse and Dependence project. The methods developed in this dissertation were designed for the purpose of analyzing a subset of the Pathways data that includes demographics, cannabis use metrics, personality measures, and imputed genotypes (SNPs) for 493 complete twin pairs (986 subjects.) The primary goal was to determine what combination of SNPs and additional covariates may predict cannabis use, measured on an ordinal scale as: “never tried,” “used moderately,” or “used frequently”. To conduct this analysis, we extended the ordinal Generalized Monotone Incremental Forward Stagewise (GMIFS) method for mixed models. This extension includes allowance for a unpenalized set of covariates to be coerced into the model as well as flexibility for user-specified correlation patterns between twins in a family. The proposed methods are applicable to high-dimensional (genomic or otherwise) data with ordinal response and specific, known covariance structure within clusters.

Background: Polysubstance use (PSU) is common among patients with cannabis use (CU) and is related to more severe CU problems. However, it is unclear how PSU predicts CU treatment outcomes beyond CU patterns. We examined the frequency, amount, and class of additionally used substances as predictors for primary and secondary outcomes. Methods: We conducted crude and adjusted regression analyses for PSU variables as predictors of remission, abstinence, reduction, and secondary outcomes in 166 help-seeking patients from a randomized clinical trial of CANDIS, a cognitive behavioral treatment program. Results: Patients with recent illegal PSU experienced more difficulties in reducing their CU (B = –1.22, p < 0.001). In contrast, remission rates were slightly higher in patients with a wide variety of last-year-PSU (RD = 0.04, p < 0.001). Amphetamine use predicted poorer outcomes regarding CU-related problems (B = –4.22, p = 0.019), and the use of opiates, inhalants, and dissociative substances predicted poorer physical health outcomes (B = –0.62, p = 0.009; B = –0.96, p = 0.039; B = –1.18, p = 0.007). Conclusions: CU treatment is also effective for patients with moderate PSU. However, treatment effects may be enhanced by addressing specific PSU characteristics as part of a modularized program.