I investigated the longitudinal relationship between alcohol use, cannabis use and cigarette smoking and serious violence using data from a prospective longitudinal, nationally representative cohort of 17,519 individuals interviewed on 4 occasions. Participants were between 12 and 17 years of age at wave I and were between 23 and 32 year of age at wave IV. There was a linear relationship between the number of drinks consumed but not frequency of drinking alcohol and violence. The number of individuals needed to abstain from drinking alcohol to prevent one from becoming violent was estimated. Smokers were also twice as likely to report subsequent violence within the next year, however there was no relationship between cannabis use and incident violence within the next year. Analysis of the entire cohort (whether or not they reported violence at baseline) incorporated individual change in substance use over time to investigate the longitudinal relationship between substance use and violence. Moderate drinkers were approximately 1.4 times more likely to be violent than non-drinkers. Cigarette smoking and cannabis use was also associated with similar increases, but heavier drinkers were more than twice as likely to report serious violence. When the trajectories of violence were investigated, predictive marginal effects showed that drinking 1-4 drinks on each occasion was associated with an increased risk of violence during adolescence, but as the individuals got older the risk of violence tended to converge with that of non-drinkers by age 20. Heavier drinking however, was associated with a greater risk of violence well into adulthood, although the trajectories tended to converge by age 30. The relationship between personality traits, alcohol and violence was then investigated using structural equation modelling. Alcohol was found to mediate the association between violence and specific personality characteristics, especially anger/hostility and extroversion.

Smokers attend preferentially to smoking-related cues in the environment, known as attentional bias. Evidence suggests that attentional bias is related to craving and relapse. Attentional retraining (AR) procedures have been used in laboratory studies to modify attentional bias and processes related to drug use, but investigations on the clinical value of AR in addiction are scarce. This thesis reports on two randomised controlled trials investigating the efficacy of AR with modified visual probe tasks in smokers. The first study explored the effects of varying the length of AR on attentional bias, craving, mood and withdrawal in current smokers. No retraining effects were observed after either a short, medium or long block of AR. The second study explored the efficacy of AR on attentional bias and smoking cessation outcomes in treatment-seeking smokers. While AR procedures were feasible to deliver within smoking cessation clinics, the intervention did not significantly reduce attentional bias, craving, withdrawal symptoms or the likelihood of relapse. These results and the literature in general show that there is no clear association between attentional bias and craving and relapse. Current AR procedures are not effective in smokers and should not be used in smoking cessation treatments, as they currently stand.

Caffeine is the most widely consumed socially acceptable drug in the world and is commonly used for its ergogenic properties with demonstrated performance enhancing effects in endurance, power and strength based activities. Despite a wealth of evidence concluding a caffeine induced performance benefit, the direct effects of the drug on peripheral physiological processes have not been fully examined. Early works showed high dose caffeine has direct force potentiating effect on skeletal muscle, a notion that has only recently been confirmed by James et al. (2005) to also occur at a maximal human physiological concentration (70µM). The present research, using mouse muscle as a model for mammalian muscle in general, provides an in-depth assessment of the direct effect of physiological concentrations of caffeine on isolated skeletal muscle performance. This research uniquely: quantifies the dose response relationship; assesses the effects of caffeine on maximal and sub maximal muscle power output and fatigue; looks at the relationship between muscles with different fiber type compositions. As high concentrations of caffeine and taurine are a constituent of many energy drinks, the suggested interaction of these ingredients to further potentiate muscle mechanical performance was also assessed. The study further examines how mammalian muscle mechanical properties change over an age range of development to aged, and how this differs between muscles with predominantly different anatomical locations and functions. In light of this the age related direct effect of physiological concentrations of caffeine was assessed in order to examine whether the ergogenic benefit changed with age. The present results demonstrate a direct muscle performance enhancing effect of physiological concentrations of caffeine that is likely to promote greater benefit on long duration endurance based activities. Furthermore, the present study demonstrates that there is no direct effect of physiological concentrations of taurine and no further performance enhancing benefit when combined with caffeine. Finally this research uniquely highlights the muscle specific age related changes in mechanical performance and further indicates that the direct effect of caffeine changes with age.

Contexte : Les troubles liés à l’usage des substances psychoactives constituent une priorité de santé publique dans le champ des pathologies chroniques. Les indicateurs de type Patient-Reported Outcomes (PRO) offrent des perspectives complémentaires aux indicateurs classiques pour la mesure de l’état de santé des patients et l’appréciation de la qualité des soins. Objectifs : Étudier les propriétés psychométriques de questionnaires de qualité de vie (QV) et les déterminants de la satisfaction précoce vis-à-vis des soins ambulatoires de patients dépendants aux substances de type alcool ou opiacés. Méthode : Les caractéristiques des patients et des médecins ont été recueillies à l’inclusion dans la cohorte SUBUSQOL. La satisfaction précoce a été mesurée quinze jours après la première consultation et ses déterminants ont été testés dans des modèles de régression linéaires multivariés. Les propriétés psychométriques du questionnaire spécifique Q-LES-Q-SF ont été étudiées au préalable sur un échantillon de patients. Résultats : La version française du Q-LES-Q-SF constitue un outil unidimensionnel robuste et fiable, les items du SF-12 et Q-LES-Q-SF présentent peu ou pas de fonctionnement différentiel selon l’âge, le sexe, le niveau d’éducation et le type d’addiction. Peu de variables recueillies sont associées à la satisfaction. Les patients dépendants à l’alcool se révèlent être plus satisfaits des modalités de contact et du délai de rendez-vous et ceux sans aucun antécédent de prise en charge pour leur dépendance plus satisfaits de leur consultation avec le médecin. Conclusion : Les questionnaires SF-12 et Q-LES-Q-SF peuvent être utilisés dans des populations de patients suivis en ambulatoire pour une dépendance aux substances psychoactives / Context: Of chronic diseases, substance use disorders are a public health priority. Patient-reported outcome indicators (PRO) offer additional insights into the classical indicators used to measure the patient’s health status and appreciation of their quality of care. Objectives: to study the psychometric properties of quality of life instruments and to study the determinants of early outpatient satisfaction with ambulatory care in alcohol- or opiate-dependent patients. Method: Patient and physician characteristics were collected in the SUBUSQOL cohort. Early satisfaction with care was measured fifteen days after the first consultation. The determinants of satisfaction were tested using multivariate linear models of regression. Prior data on the self-reported health status of a sample of alcohol- or opiate-dependent outpatients were used to investigate the psychometric properties of a specific questionnaire, the Q-LES-Q-SF. Results: Our results establish that the French version of the Q-LES-Q-SF is a unidimensional, valid and reliable instrument of self-reported health status assessment for use in care or medical research and that few items of the SF-12 and the Q-LES-Q-SF displayed differential functioning according to age, sex, educational level and type of substance use disorder. Our results show that few variables are associated with the level of patient satisfaction. Alcohol dependence was strongly associated with higher satisfaction with appointment making, and patients with no history of previous care for substance use disorders had a higher level of satisfaction with the doctor consultation. Conclusion: The use of the SF-12 and the Q-LES-Q-SF is recommended for outpatients suffering from substance use disorders

Durant les années 1990, en France, en Suisse et au Québec, de nouveaux médicaments ont reçu une autorisation de mise sur le marché, dans le cadre de la prise en charge de la dépendance aux opiacés. Vingt cinq ans plus tard, notre thèse interroge les usages qu’en font les personnes en traitement. A partir de la méthode biographique, nous étudions la substitution en terme d’« ajustements ». Les détournements de l’usage prescrit des TSO, étiquetés comme « mésusages » par les pouvoirs publics et un certain nombre de praticiens, apparaissent dès lors comme une modalité d’adaptation et de réappropriation du traitement. En évaluant les convergences et les divergences dans les pratiques et leurs effets, la comparaison de nos trois terrains d’enquête nous permet d’analyser les différents sens associés à la substitution, selon les contextes et les structures de soin au sein desquels l’usager est accueilli. / For a long time, ending drug addiction meant completely stopping any consumption. In the context of harm reduction policies, the introduction of substitution treatments has drastically changed the abstinence paradigm. Ending an addiction has taken a plural meaning, adding complexity to the delimitation already porous between “normal and pathological”. Nowadays stabilizing Methadone maintenance treatment or taking drugs on an irregular basis are perceived as an alternative to abstinence or other forms of recovery. In this thesis, wiitch deals with polysemic uses of substitution treatment, we analyze the attempts and strategies of the adjustment process in entering an addiction centre. The aim of this study is to show the different competencies that people can display in situations of vulnerability. Our interest is to find out how valuable expertise can emerge from the layperson point of view.

Suivant le parcours de leurs vies, les toxicomanes vivent le chaos ; ils n’arrivent pas à voir le bout du tunnel. Ils ne savent pas réfléchir d’une façon constructive, profiter des opportunités et d’élaborer des plans bien déterminés pour se réaliser. L’adoption du toxicomane de la gestion de soi peut contribuer à développer chez lui les capacités d’observation, de réflexion, d’analyse, de contrôle de soi… D’après les résultats obtenus, nous pouvons constater que : 1. Les toxicomanes ont plus de difficultés cognitives que les non toxicomanes. 2. Le sentiment de satisfaction personnelle chez les toxicomanes est plus bas que chez les non toxicomanes. 3. La stabilité émotionnelle positive chez les non toxicomanes est beaucoup plus grande que celle des toxicomanes 4. La stabilité émotionnelle négative chez les toxicomanes est plus développée que chez des non toxicomanes. La gestion de soi aide le toxicomane à intégrer le plaisir dans la vie relationnelle, comme elle peut l’aider à appliquer les qualités acquises et préparer de nouvelles expériences. / Following the path of their life, the drug addicts live the chaos; they fail to see the end of the tunnel. They don’t know how to think in a constructive way, to take advantages of opportunities and to develop plans well determined to be achieved. The adoption of the drug addicts self-management can help to develop his capacity of observation, reflection, analysis, self-control… Regarding the obtained results, we note the followings observations: 1. The drug addicts show more cognitive difficulties than the non addicts. 2. The addicts show less self satisfaction than non addicts. 3. The drug addicts show a much more positive emotional stability than non addicts. 4. The drug addicts show as well a more negative and developed emotional stability than non addicts. The self-management helps the drug addicts to integrate the pleasure in the relationships as it may help to apply the acquired qualities and to prepare new experiences.

L’objectif majeur de cette thèse a été d’appréhender les conséquences de la comparaison sociale sur l’auto-évaluation implicite et explicite en termes de prudence, les affects et les comportements à risque. Les participants ont été exposés à un standard de comparaison prudent (standard haut) ou imprudent (standard bas) en matière d’alcool. Les résultats montrent que les sujets confrontés au standard haut se perçoivent implicitement plus imprudents et ressentent plus d’anxiété que les sujets exposés au standard bas. En revanche, le standard de comparaison n’influence pas l’auto-évaluation explicite et les comportements contrôlés. Ces résultats témoignent en faveur d’une dissociation entre les processus automatiques (implicites) et contrôlés (explicites) en jeu dans la comparaison sociale. Au niveau appliqué, nos données suggèrent que dans une campagne de prévention il serait potentiellement plus efficace de mettre en scène un standard prudent plutôt que de montrer un preneur de risque. / The main goal of this PhD research was to study the consequences of social comparison on implicit and explicit self-evaluation in terms of cautiousness, on affect and on risk-taking behavior. In a series of studies, participants were exposed to a comparison standard who displayed either cautious (high standard) or reckless (low standard) drinking behavior. Results show that participants confronted with the high standard implicitly perceive themselves as more reckless and experience higher levels of anxiety than participants exposed to the low standard. On the other hand, the comparison standard does not influence explicit self-evaluation and controlled behaviors. These results indicate that there might be a dissociation between automatic (implicit) and controlled (explicit) processes involved in social comparison. On an applied level, regarding alcohol prevention campaigns, our findings suggest that it could be more effective to show a cautious standard rather than a reckless one.