College cannabis use: the unique roles of social norms, motives, and expectancies (2013)

Objective: Given that the majority of college cannabis use occurs in social situations, descriptive norms (beliefs about others' use) and injunctive norms (others' approval of risky use) may be particularly relevant to cannabis-related behaviors. Yet, little research has examined the unique impact of these norms on one's own behaviors when accounting for the variance attributable to other relevant cognitive factors. The current study is the first known investigation of the unique impact of social norms, cannabis use motives, and cannabis effect expectancies on cannabis use.
Method: Data came from 223 (64.1% female) current cannabis-using undergraduates who completed an online questionnaire in exchange for psychology-course research credit.
Results: Descriptive norms regarding friends (not students in general) and injunctive norms (friends and parents) were related to cannabis use frequency. Descriptive norms (friends, not students in general) and injunctive norms (friends, not parents) were related to cannabis problems. Relevant norms, expectancies, and motives accounted for 66.8% of the variance in cannabis use frequency and 28.7% of the variance in cannabis problems. In multivariate analyses, descriptive norms (friends) accounted for the greatest amount of unique variance in cannabis use frequency, whereas coping motives accounted for the greatest amount of unique variance in cannabis-related problems.
Conclusions: Descriptive norms (friends) and coping motives may be two cognitive vulnerability factors that could be particularly important targets for interventions.