Contributions of social influences and expectations of use to cannabis use in high-school students.

The aim of the study was to evaluate the relative contributions of peers cannabis use or non-use, parental approval of such use, adolescents' own beliefs about use, to the prediction of cannabis use. The participants were 559 high-school students who completed questionnaires assessing the frequency of cannabis use, the number of peers using cannabis, the number of peers opposed to cannabis use, parental attitude toward cannabis use, and participants' expectations towards use. The number of peers using cannabis and participants' positive expectations of cannabis use were risk factors for use whereas the number of peers opposed to cannabis use and the negative expectations of use were protective factors. Parental attitudes towards use were not a significant independent predictor of use.