Cannabis dependence in young adults: an Australian population study

FRANÇAIS :
Dans une population représentative de 1601 jeunes adultes en 1998, l'usage de cannabis, les symptômes de dépendance et la différence de symptomatologie entre les syndromes alcoolique et cannabique sont étudiés. 59% rapportent une consommation hebdomadaire de cannabis au cours de leur vie et 7% repondent aux critères de dépendance du DSM-IV. La prévalence des symptômes est la suivante : un désir permanent (91%), un usage non-intentionnel (84%); un manque (74 %), un temps excessif de recherche du produit (74%), un usage poursuivi malgré des problèmes de santé (63%), une tolérance (21%) et des conséquences sociales (18%). Les personnes dépendantes du cannabis déclarent des usages compulsifs et non contrôlés plus fréquement que les consommateurs d'alcool dépendants, un manque similaire et beaucoup moins de tolérance.
ENGLISH :
Objectives. The symptomatology of cannabis dependence remains ill-defined and its importance controversial. Compared with alcohol dependence, the symptom profile of cannabis dependence has received little attention. We aimed to (a) report cannabis use in a representative population of young adults, (b) examine cannabis dependence symptoms according to frequency in the dependence syndrome and (c) contrast the symptomatology of cannabis and alcohol syndromes. Methods. 1601 young adults (mean age 20.7 years) from an Australian longitudinal cohort study (N = 2032) were surveyed in 1998. Regular substance users were assessed for DSM-IV cannabis and alcohol dependence. Prevalence estimates allowed for sampling variation and attrition. Results. Fifty-nine per cent reported life-time use of cannabis, 17% used at least weekly and 7%, (11%, males, 4%, females) met criteria for cannabis dependence. Symptom prevalence in dependent cannabis users was: persistent desire 91 %; unintentional use 84%; withdrawal 74%; excessive time obtaining/using 74%; continued use despite health problems 63%; tolerance 21%; and social consequences 18%. The combination of withdrawal, persistent desire and unintentional use was reported by 57%. Dependent cannabis users reported compulsive and out-of-control use more frequently than dependent alcohol users, withdrawal similarly and tolerance considerably less often. Conclusions. Cannabis use appears to be normative behaviour in young Australians. Progression beyond weekly use of cannabis carries a significant risk of dependence that should be considered in the public health response. The differing profiles of cannabis and alcohol dependence, particularly with regard to craving, draws attention to the need for further study of cannabis dependence as an important and distinct disorder in young adults. (Author' s abstract)