Pour comprendre l'étiologie de l'alcoolisme et des addictions aux autres drogues, il est nécessaire de connaître la fréquence d'utilisation des substances dans des cohortes de jeunes adultes et le rôle des vulnérabilités spécifiques qui peuvent expliquer le développement de tels troubles. Nous nous proposons d'examiner ces questions à partir d'un large échantillon d'étudiants et porterons une attention particulière au facteur de risque qu'est la comorbidité. Concernant leur utilisation récente de substances, 1517 participants ont fourni des informations, et les sous-groupes représentatifs des utilisateurs fréquents ont ensuite suivi un entretien clinique. Nos résultats indiquent le maintien des tendances observées depuis 2000 concernant la stabilisation de l'utilisation d'alcool, la diminution du tabac et l'augmentation de la consommation de cannabis chez des jeunes du même âge. Le pourcentage de troubles psychiatriques était généralement plus élevé dans les groupes consommant des substances que dans le groupe témoin, mais ces différences étaient significatives uniquement pour les consommateurs des substances les plus illicites. Ces résultats sont discutés en termes de facteurs de risque pour les troubles liés à l'utilisation de substances ainsi que leurs conséquences sur la prévention.

Understanding the etiology of alcoholism and drug addiction requires knowledge of the frequency of substance use in young cohorts, as well as the role of specific vulnerabilities that may explain the later development of these disorders. In the public health domain, efficient programs of prevention depend on the understanding of substance use in general population. The present study examined these issues in a large sample of university students, with particular attention to the risk factor of comorbid psychopathology.

A two-phase sampling plan was used with post-stratification on substances use. In the first stage, an initial sample of 1517 students was pre-selected based on responses to a battery of self-questionnaires, including information concerning recent consumption of substances (alcohol, cannabis, cocaine, heroin, acid, solvents...). 224 subjects were then selected in the second phase to compose four groups of substance users: infrequent consumers (those who did not use any substance during the last month; N=80); frequent consumers of alcohol only (with a consumption of alcohol of several times a week to several times a day, regardless of tobacco use but with no other substance use; N=44), frequent consumers of cannabis (consumption of cannabis of several times a week to several times a day, regardless of tobacco and alcohol use but with no other substance use; N=54) and consumers of other illicit substances (consumption of hallucinogens, cocaine, heroin, ecstasy, or other illicit substance at least once during the last month; N=46). These representative subgroups of infrequent and frequent users were then administered a psychiatric diagnostic interview (Mini International Neuropsychiatric Interview; MINI, version 5.0) to assess affective and mood disorders and substance use disorders. At the end of the study, all participants received 75 € ($100).

The findings indicate maintenance of trends observed in France since 2000 for the stabilisation of alcohol use, a decrease in tobacco use, and an increase in cannabis among this age cohort. Nevertheless, it's important to note that these frequencies are based on frequent use of substances and, even if most of users do not fulfil criteria for abuse or dependence, such levels of consumption may have serious consequences for daily functioning and physical or mental health. In examining this issue, the percentage of comorbid psychopathology was found to be generally higher in substance using groups than in the control group, but these differences were significant only for consumers of illicit drugs. The findings are discussed in terms of consequences for the overall psychosocial functioning of young substance users and relative to the increased risk of developing a substance use disorder.