Cette étude a évalué la fréquence et les modes de consommation du cannabis chez 210 adolescents (âge moyen = 16,3 1,3) ainsi que les représentations des effets plaisants, déplaisants ou négatifs, des risques physiques, des risques de tolérance, des symptômes de sevrage, de dépendance et des perturbations du fonctionnement scolaire, social et familial. Les usagers du « bang » ou pipe à eau rapportent des effets brusques et violents qui rapprochent le cannabis d’une drogue dure. Les consommateurs de cannabis ont rapporté significativement plus fréquemment que les non consommateurs des effets plaisants et significativement moins fréquemment, des effets déplaisants ou négatifs, les risques physiques, les risques de tolérance, de symptômes de sevrage, de dépendance et de retentissement scolaire, social et familial. Aucun sujet n’a mentionné le risque d’accident de la circulation. Ces résultats suggèrent qu’une information sur les effets négatifs du cannabis, ses risques, ses conséquences scolaires, sociales et familiales peut être une cible pour la prévention.

The aim of the study was to compare perceptions of cannabis use effects and risks of tolerance effect, withdrawal syndrome, dependence and repercussions on school, social, and familial functioning among adolescent cannabis users and non users. Subjects were 210 adolescents (121 boys, 89 girls ; mean age = 16.3 1.3) from the department of Pyrénées-Orientales, France. Subjects completed a questionnaire assessing the frequency of cannabis use, the method of using cannabis, and including open-ended questions (What are the different methods of cannabis use ? What are their pleasant and unpleasant or negative effects ? What are their risks ? Do you think that cannabis effects decrease in intensity when you are used to it ? When someone is used to cannabis and stop using it (or has no more of it), does she experience craving for cannabis and withdrawal symptoms ? What do you think of cannabis use ?). Among the subjects, 118 (56.2 %) were cannabis users and 92 (43.8 %) were non-users. Among users, 27 % used cannabis once a month or less than once a month, 21 %, more than once a month ; 24 %, more than once a weeks ; 6 %, every day ; 20 %, more than once a day. The methods of using cannabis were joints (76 %), bong (40 %), pipe (23 %), and ingestion (18 %). Knowledge of methods of using cannabis was higher in users than non-users : joint (87 % vs 64 %, p ≪ 0.0001), bong (69 % vs 21 %, p ≪ 0.0001), pipe (38 % vs 7 %, p ≪ 0.0001), ingestion (41 % vs 13 %, p ≪ 0.0001). Fifty-four per cent of users reported that cannabis use induces pleasant affects versus 30 % of non-users (p = 0.0006). They were exhilaration (47 % vs 9 %), relaxation (40 % vs 23 %), cheerfulness (21 % vs 10 %). Twenty-seven percent of users reported that cannabis use reduces negative feelings versus 14 % of non-users (p = 0.02). To be more open to social relationships was mentioned by 13 % of users versus 1 % of non-users (p = 0.0001). The negative effects that were reported were attention and cognitive impairment (13 % of users vs 5 % of non users, p = 0.05), irritability (8 % vs 8 %), loss of control (8 % vs 8 %) and feeling faint (13 % vs 6 %, p = 0.09). Users reported than bong has much quicker and stronger effects than joints. The effects of bong class cannabis as a hard drug. Physical negative effects or risk were reported by 35 % of users versus 30 % of non-users (p = 0.44). Bong users described specific physical risks such as respiratory problems and fainting. No subjects reported the risk of road accidents. Most users and non-users considered that cannabis use causes dependence (60 % vs 74 %, p = 0.03), tolerance (68 % vs 60 %, p = 0.23), and withdrawal symptoms (76 % vs 52 %, p ≪ 0.001). A minority of users and non-users reported that cannabis use causes a deterioration in school functioning (42 % vs 20 %, p = 0.69), in social activities (23 % vs 14 %, p = 0.10) and in family relationships (29 % vs 20 %, p = 0.14). Most of users (56 %) had a global positive opinion of cannabis use whereas most non-users (66 %) had a global negative opinion of cannabis use. The frequency and methods of use reported in this study compare with the results of a recent study carried out in another town of the south of France. These results suggest that a high proportion of French adolescents are using cannabis and that a high proportion of users utilize bongs. Perception of cannabis effects and risks of tolerance effect, withdrawal syndrome, dependence and repercussions on school, social, and familial functioning differed between users and non-users. Users have more positive beliefs and less negative beliefs about cannabis than non-users. Users reported more frequently pleasant effects and less frequently unpleasant or negative effects, physical risks, risks of dependence, deterioration in school, social, and familial functioning than non-users. However, only a minority of non-users reported negative effects or consequences of cannabis use. None subjects reported a risk of road accident. These results suggest that information on negative effects, risks and repercussions of cannabis use may be a target for prevention intervention.