Decision-making is comprised of an incredibly varied set of behaviours. However, all vertebrates tend to repeat previously rewarding actions and avoid those that have led to loss, behaviours known collectively as the win-stay, lose-shift strategy. This response strategy is supported by the sensorimotor striatum and nucleus accumbens, structures also implicated in spatial processing and the integration of sensory information in order to guide motor action. Therefore, choices may be represented as spatial-motor actions whose value is determined by the rewards and punishments associated with that action. In this dissertation I demonstrate that the location of choices relative to previous rewards and punishments, rather than their identities, determines their value. Chapters 2 and 4 demonstrate that the location of rewards and punishments drives future decisions to win-stay or lose-shift towards that location. Even when choices differ in colour or shape, choice value is determined by location, not visual identity. Chapter 3 compares decision-making when two, six, twelve, or eighteen choices are present, finding that the value of a win or loss is not tied to a single location, but is distributed throughout the choice environment. Finally, Chapter 5 provides anatomical support for the spatial-motor basis of choice. Specifically, win-stay responses are associated with greater oscillatory activity than win-shift responses in the motor cortex corresponding to the hand used to make a choice, whereas lose-shift responses are accompanied by greater activation of frontal systems compared to lose-stay responses. The win-stay and lose-shift behaviours activate structures known to project to different regions of the striatum. Overall, this dissertation provides behavioural evidence that choice location, not visual identity, determines choice value. / Thesis / Doctor of Philosophy (PhD)

INTRODUCTION: The legal and illicit use of cannabinoid-containing products is accelerating worldwide and is accompanied by increasing abuse problems. Due to legal issues, the USA will be entering a period of rapidly expanding recreational use of cannabinoids without the benefit of needed basic or clinical research. Most clinical cannabinoid research is focused on adults. However, the pediatric population is particularly vulnerable since the central nervous system is still undergoing developmental changes and is potentially susceptible to cannabinoid-induced alterations. RESEARCH DESIGN AND METHODS: This review focuses on the systems medicine of cannabinoids with emphasis on the need for future studies to include pediatric populations and mother-infant dyads. RESULTS AND CONCLUSION: Systems medicine integrates omics-derived data with traditional clinical medicine with the long-term goal of optimizing individualized patient care and providing proactive medical advice. Omics refers to large-scale data sets primarily derived from genomics, epigenomics, proteomics, and metabolomics.

No description available.

No description available.

Au Canada, 13 % de la population consomme des drogues illicites et il est estimé qu’un jeune sur trois consomme régulièrement du cannabis. Cela génère un fardeau social, coûtant 46 milliards de dollars et entraînant l’hospitalisation de 275 000 personnes. La compréhension des facteurs de risque et des processus menant au développement d’une consommation problématique du cannabis et des autres substances chez les jeunes s’avère ainsi critique. Bien que plusieurs facteurs individuels et environnementaux soient impliqués dans le développement d’une consommation problématique du cannabis et des autres substances, l’adversité à l’enfance et le tempérament impulsif sont identifiés comme deux facteurs de risque importants pour le développement d’une consommation problématique. Cependant, aucune étude n’existe dans la prédiction spécifique des problèmes de consommation du cannabis. L’objectif principal de cette étude a été d’examiner le rôle de l’adversité et de l’impulsivité à l’enfance dans la prédiction d’une consommation problématique du cannabis et des autres substances à l’âge de 24 ans chez des Québécois suivis depuis de leur naissance, et ce dans le cadre d’une étude de cohorte longitudinale. Une relation a été trouvée entre l’adversité à l’enfance et la consommation problématique des substances autres que le cannabis. On retrouve également l’impact de l’impulsivité en tant que facteur de risque pour la consommation problématique des substances autres que le cannabis. Dû à l’absence de résultat significatif quant à la consommation problématique du cannabis, davantage d’études sont nécessaires afin d’explorer son lien avec l’adversité à l’enfance et l’impulsivité. / In Canada, 13% of the population uses illicit drugs and it is estimated that one individual out of three regularly between the ages of 16 to 25 consume cannabis on a regular basis. This creates a social burden, costing $46 billion and leading to the hospitalization of 275,000 individuals. Understanding the risk factors and processes leading to the development of cannabis and other substance use problems in young adult is therefore critical. While it is evident that several individual and environmental factors are involved in the development of cannabis and other substance use problems, childhood adversity and impulsivity have been identified as two important risk factors for the development of problematic cannabis and other substance use. However, there are no studies that examines the specific prediction of cannabis use problems. Thus, the main objective of this study was to examine the role of childhood adversity and impulsivity in the prediction of cannabis use problems in Quebec young adults at age 24, followed since birth in a longitudinal cohort study. A relationship was found between childhood adversity and problematic use of substances other than cannabis at age 24. We also found the impact of impulsivity as a risk factor for problematic consumption of substances other than cannabis. Due to the lack of significant results regarding problematic cannabis use, more studies are needed to explore the link between problematic cannabis use, childhood adversity and impulsivity.

Objectif: La prévalence de la consommation de cannabis chez les Inuits du Nunavik est l’une des plus élevées au monde, particulièrement chez les adolescents, et les facteurs permettant d’expliquer ce phénomène demeurent mal connus. Selon Bronfenbrenner (1979), la famille est l’unité la plus proximale de l’adolescent et est susceptible d’influencer particulièrement ses comportements. L’objectif de cette étude est d’examiner de manière longitudinale l’association entre la consommation de cannabis de mères inuites et de leurs adolescents. Hypothèses : Une fréquence de consommation plus élevée chez les mères sera associée 1- à une initiation plus rapide au cannabis et 2- à une consommation plus fréquente chez leurs adolescents. Méthode : Les données utilisées proviennent de l’étude de cohorte prospective Nunavik Child Development Study (NCDS). Ce mémoire utilise les données de deux périodes de collecte, l’une survenue entre 2005 et 2010 (T1 : temps 1, jeunes 8-15 ans), et l’autre entre 2012 et 2016 (T2 : temps 2, jeunes 16-22 ans). Des entrevues structurées ont permis d’évaluer la consommation de cannabis des participants et d’autres variables concomitantes chez la mère à T1 et chez son adolescent à T2. L’échantillon analysé compte 184 dyades mère-adolescent. Des analyses de régression ordinale et de Cox ont été réalisées pour vérifier les hypothèses. Résultats : Aucune association significative n’a été identifiée entre la fréquence de consommation des mères et l’âge d’initiation au cannabis, de même que la fréquence de consommation de cannabis de leurs adolescents. Par ailleurs, un statut socioéconomique élevé et la fréquentation scolaire sont associés à un moindre risque de consommer fréquemment du cannabis chez les adolescents. Conclusion : L’association attendue entre la consommation maternelle et l’usage de cannabis de jeunes Inuits n’a pas été retrouvée. La recherche de prédicteurs à l’usage de substances reste d’actualité afin de minimiser le cumul de vulnérabilités que vivent les populations autochtones. / Aim: Adult and adolescent Inuit from Nunavik show some of the highest prevalence of cannabis use in the world, particularly for youth. Knowledge of the factors that explain this phenomenon in this region is lacking. According to Bronfenbrenner (1979), family is the closest unit for adolescents and is susceptible to particularly influence their behaviors. The aim of this longitudinal study is to examine longitudinally the association between maternal use of cannabis and the subsequent use of this substance by their adolescents in an Inuit population. Hypothesis: A higher cannabis frequency use among mothers will be associated 1- with more rapid initiation of cannabis, 2- and more frequent use among their adolescent. Method: This study was based on longitudinal data from the Nunavik Child Development Study (NCDS). This study used data from two follow-ups, between 2005 and 2010 (T1: time 1, youth: 8-15 years old), and between 2012 and 2016 (T2: time 2, youth: 16-22 years old). Structured interviews were used to assess maternal cannabis use and other concomitant variables at T1, and for adolescents at T2. Our sample included 184 mother-adolescent dyads. Hypotheses were tested using a Cox regression analysis and ordinal regressions. Results: No significant associations were found between mothers’ frequency of cannabis use and adolescents initiation age as well as regarding the adolescents’ frequency of cannabis use. Nevertheless, a higher socioeconomic status and going to school were associated with a lower risk of frequent cannabis use by the adolescents. Conclusion: The expected association between maternal cannabis consumption and cannabis use of young Inuit was not found. The search for predictors of substance use remains relevant to minimize the accumulation of vulnerabilities experienced by Aboriginal populations.

The agricultural sector plays a crucial role in securing a more sustainable livelihood for the world's growing population. An expanded cultivation of multifunctional and environmentally smart crops like industrial hemp (Cannabis sativa L.) can thus be part of the solution in meeting the increasingly high demands of sustainable development. However, earlier research indicates that the global cultivation of industrial hemp is hindered, and that hemp is an underutilized resource relative to its potential benefits. During the 20th century hemp cultivation was banned in large parts of the world. Sweden lifted the ban in 2003, later than most other European countries. In 2017, Swedish hemp cultivation was by far one of the smallest in the European Union. This study thus aims to analyze the position of industrial hemp in Sweden – by using the theoretical framework of political ecology – to investigate which social and societal structures and processes that dictates the access to and the control of industrial hemp in Sweden today. A historical analysis of power relations as well as ideological and cultural contexts – with significance for the cultivation of hemp – is done to make the relationship between Cannabis sativa L. and Swedish society appear more clearly. The material for the analysis has been collected through a literature search and qualitative method using in-depth interviews with Swedish authorities and a national hemp association. The study discusses the relationship between hemp and human society, which is found to be characterized by a complex interconnectedness.  Furthermore, the study shows that Swedish industrial hemp production is negatively affected by, among other things, cultivation bans, strict regulations, government controls, drug conservatism, and group as well as state conformity. Through a more progressive policy, industrial hemp is expected to become a positive contributing factor to reduced greenhouse gas emissions and to a growing fossil-free bio-based industry.

Looking primarily at the social and political trends in South Africa over the course of the last century and a half, this thesis explores how these trends have contributed to the establishment of the southern Africa cannabis complex. Through an examination of the influence which the colonial paradigm based on Social Darwinian thinking had on the understanding of the cannabis plant in southern Africa, it is argued that cannabis prohibition and apartheid laws rested on the same ideological foundation. This thesis goes on to argue that the dynamics of cannabis production and trade can be understood in terms of the interplay between the two themes of ‘prohibition’ and ‘resistance’. Prohibition is not only understood to refer to cannabis laws, but also to the proscription of inter-racial contact and segregation dictated by the apartheid regime. Resistance, then, refers to both resistance to apartheid and resistance to cannabis laws in this thesis. Including discussions on the hippie movement and development of the world trade, the anti-apartheid movement, the successful implementation of import substitution strategies in Europe and North America from the 1980’s, and South Africa’s incorporation into the global trade, this thesis illustrates how the apartheid system (and its collapse) influenced the region’s cannabis trade.

Selon la théorie de l'escalade, l'usage de tabac ou d'alcool est associé à l'usage de cannabis, qui peut lui-même conduire à l'usage d'autres drogues illicites (ADI). L'objectif de notre étude était de décrire les transitions entres usages de drogues licites, de cannabis et d'ADI. Les données de deux enquêtes en population générale (ESCAPAD pour l'adolescent et Baromètre santé pour l'adulte jeune (année 2005)) ont été utilisées. Les âges rapportés d'initiation des différentes substances ont permis de définir les étapes d'usages. L'analyse des transitions entre substances a été réalisée grâce aux modèles structuraux et aux modèles multi-états de Markov en prenant en compte certains cofacteurs. Les données recueillies ont permis de décrire un processus d'usage de substances partant des drogues licites et menant vers les ADI via le cannabis. Ces résultats étaient compatibles avec la théorie de l'escalade décrite par Kandel en 1975 et étaient renforcés par certains critères : force/stabilité des associations, effet dose-réponse, cohérence avec la littérature et relation temporelle. La théorie qui se dégage de nos travaux pourrait être celle d'opportunités en chaîne, l'apprentissage de la première substance psychoactive étant conditionné à son accessibilité et susceptible d'offrir des opportunités ultérieures d'usages d'autres substances. Il est cependant important de souligner que la théorie de l'escalade, si elle semble correspondre à la majorité des séquences d'usages observées, est actuellement remise en question par certains auteurs qui lui préfèrent l'idée d'un facteur de vulnérabilité commun aux addictions.

Les enfants présentant un niveau élevé d’agressivité physique sont davantage à risque de commettre des actes criminels à l’âge adulte. Ces enfants sont également plus à risque de consommer des substances psychoactives au cours de leur adolescence. Les études portant sur le lien entre la consommation de substances psychoactives et la criminalité arrivent à des conclusions différentes, dépendamment des substances à l’étude et des comportements criminels ciblés. Un lien positif a été démontré entre la consommation chronique d’alcool et la perpétration d’actes criminels contre la personne et contre la propriété, tandis que la consommation de cannabis a été associée positivement aux actes criminels contre la propriété et négativement aux crimes contre la personne. La présente étude visait à tester l’hypothèse que l’agressivité physique manifestée à l’enfance est associée à une augmentation du nombre de charges criminelles durant l’âge adulte et que cette association est spécifique au type de criminalité et modérée différemment par la consommation d’alcool et de cannabis durant l’adolescence. À cette fin, 887 participants de sexe masculin provenant de milieu défavorisé ont été suivis de 6 à 25 ans. Les analyses de régressions logistiques multinomiales indiquent que les individus cheminant sur une trajectoire modérée ou élevée d’agressivité physique durant l’enfance sont plus à risque de commettre des actes criminels. Cette association reste significative après avoir contrôlé pour l’adversité familiale et de la consommation de substances psychoactives. Les hypothèses des effets modérateurs de la consommation d’alcool et de cannabis sont infirmées. Toutefois, des effets principaux de la consommation d’alcool sur les crimes contre la personne et de la consommation de cannabis sur les crimes contre la propriété sont observés. Les implications de ces résultats sont discutées. / Individuals exhibiting high levels of physical aggression during childhood are more at risk of criminal behaviors during adulthood regardless of the presence of several risk factors. Aggressive children are also more at risk of using psychoactive substances during adolescence. Studies of the relationship between substance use and crime have provided different conclusions, depending on the substance under consideration and depending on the category of crime. Alcohol consumption has been positively associated with crimes, both against people and against property. Cannabis consumption has been associated positively with crime against property and negatively with crime against people. This present study aimed at investigating the hypothesis that physical aggression manifested in childhood is associated with an increase in criminal charges during adulthood and that association is specific to the type of crime and moderated differentially by alcohol and cannabis use. To this end, 887 male participants from lower socioeconomic status were followed from age 6 to age 25. Multinomial logistic regressions indicate that individuals belonging to a moderate or a high trajectory of physical aggression during childhood are more likely to commit crimes later in adulthood. This association remains significant after control of family adversity and drug use. Alcohol and cannabis use during adolescence has no effect on this association. However, main effects of alcohol use on crimes against person and cannabis use on crimes against property are observed. The implications of these findings are discussed.