Objectives: To evaluate the relative contributions of peers cannabis use or non use, parental approval of such use, adolescents' own beliefs about use, self-esteem, and depressive and symptoms of borderline personality disorder, in the prediction of cannabis use and dependence.
Method: Participants were 257 high-school students who completed questionnaires assessing cannabis use frequency, cannabis dependence, the number of peers using cannabis, the number of peers opposed to cannabis use, parental attitude toward cannabis use, participants' attitude toward use, self-esteem, depressive and borderline symptomatology. Logistic regression analyses were conducted to predict cannabis use, daily use and dependence.
Results: The number of peers using cannabis, participants' approval of cannabis use, and the intensity of symptoms of borderline personality disorder were risk factors for use whereas the number of peers opposed to cannabis use was a protective factor. Parental attitudes toward use and participants' depressive symptomatology were not significant independent predictors of use. There were no significant predictors of probable cannabis dependence.
Conclusion: To inform adolescents that a significant proportion of them disapprove of cannabis use may be an effective component of prevention of use. Symptoms of borderline personality disorder may account for the association between depression and cannabis use. The social influences and psychopathological factors evaluated in this study did not appear to play a major role in the development of cannabis dependence.