Consommation de substances psychoactives, problèmes affectifs et traits de personnalité : test de deux modèles d'association

FRANÇAIS :
Si l'association entre traits de personnalité, troubles affectifs et abus de substances est bien démontrée, la majorité des études porte sur des populations cliniques, ce qui empêche des conclusions sur la direction de causalité. L'objectif de cette étude est d'examiner, sur des sujets non cliniques, s'il existe des traits de personnalité précis ou des problèmes de l'humeur associés à la consommation de substances psychoactives. Deux modèles d'association ont été examinés, celui d'automédicafion et celui de déviance sociale. Fondés sur un échantillon de 685 individus, 98 sujets ont été sélectionnés pour former 4 groupes de consommation : les non-consommateurs, les consommateurs d'alcool, de cannabis et d'autres substances illicites. Seuls les consommateurs d'autres substances illicites différaient significativement des non-consommateurs et uniquement pour le trait « recherche de nouveauté ». De plus, la comparaison des 4 groupes de consommation a montré que ces scores de recherche de nouveauté augmentaient linéairement du groupe des non-consommateurs au groupe des consommateurs des substances les plus déviantes. Ceci soutient la conclusion selon laquelle le modèle de déviance sociale serait plus pertinent que celui d'automédication pour expliquer la co-occurrence de certains traits de personnalité ou problèmes affectifs et de la consommation de substances dans une population non clinique. (Résumé d'auteur.)
ENGLISH :
The International Consortium of Psychiatric Epidemiology has confirmed the high comorbidify in community-drawn samples between substance use disorders and anxiety or depression. In the same way, associations between substance use and specific personality traits (such as novelty seeking, harm avoidance orantisocial personality) have also been extensively documented. Self medication and social deviance are among the most commonly evoked explanatory models for these forms of comorbidity, and are based on findings that affective disorders and specific personality traits often precede the onset of substance use disorders. The selt-medication model postulates that an individual chooses a specific substance according to its psychopharmacologic action on the given psychological state of the person. By contrast, the social deviance model posits that this form of comorbidity is due to the fact that persons consuming certain substances may have affective or personality characteristics that are more severe or more deviant than non-consumers (or than consumers of socially well-accepted substances). In this way, the individual does not use a particular substance to assuage pre-existing disorders but, due to a more deviant personality, is less influenced by social norms and may more easily turn to using illicit substances or to polyconsumption. However, a major limitation of the current scientific literature concerning tests of these models is that previous investigations have been based in overwhelming majority on clinical populations. The examinafion only of clinical samples renders difficult the identification of causal (or primary) risk factors for the emergence of substance use disorders from the potential consequences of substance use itself. The goal of the current study was therefore to simultaneously compare both models of association using a non clinical population of substance users. In addition to selecting subjects based on use (rather than abuse or dependence), multiple comparisons were corrected with a Bonferroni adjustment. The results obtained in this non-clinical sample are in favor of social deviance model which posits that the personality trait of novelty seeking is associated to the consumption of the most illicit and deviant substances (such as heroin or cocaine). On the other hand, no support was found for the hypothesis of self medication which assumes that specific substances should be particularly associated with specific psychological charac- teristics or vulnerabilities. (From the author' s abstract)