Patterns of cannabis use, cannabis-related beliefs and dependence: study of 159 adolescent users.

Objective. - To evaluate the connections between the frequency and patterns of cannabis use and dependence, and the beliefs linked to cannabis use in a sample of adolescents. Method. - In 2001, 285 high school students (163 boys, 122 girls; mean age = 17.5 +/- 1.1 years) completed questionnaires assessing the patterns of cannabis use, and the symptoms of dependence and abuse, using a questionnaire derived from the Mini International Neuropsychiatric Interview. Cannabis-related beliefs were assessed using the Beliefs Questionnaire for Drug Addiction. Results. - Frequency of subjects who reported having used cannabis during the last year was 65.4% of boys and 42.6% of girls. Among users, 53.6% of boys and 39.3% of girls were regular users, 10.6% of boys and 7.8% of girls being daily users, Almost half of the users reported other means of consumption than "joints", in particular water-pipes or "bongs" (34.5% of boys, 26.4% of girls). Among users, near of 33% of boys and girls met the criteria for cannabis dependence. Dependence was more frequent in users practicing other means of consumption than "joints", increasing to 51% for "bong" users. Expectancies of pleasure or relief, and permissive beliefs reflecting the perception of cannabis use as risk free were higher in users and, particularly, in subjects with cannabis dependence. Regression analysis showed that these beliefs were the strongest predictors of cannabis use and dependence. Predictors of use in the total sample were expectancies of pleasure and permissive beliefs, being a male and the age of the subject. Predictors of dependence among users were expectancies of relief, frequency of use, and use of other means of consumption than "joints". Conclusions. - Cannabis use in adolescents appeared to be characterized by the frequency of use, consumption by means other than "joints" and by the frequency of dependence. Cannabis use and dependence are linked to expectancies and permissive beliefs that could be targeted for prevention and treatment. (C) 2002 Editions scientifiques et medicales Elsevier SAS.