OBJECTIVE: Socially anxious cannabis users are especially vulnerable to cannabis-related impairment, yet mechanisms underlying this vulnerability remain unclear. Socially anxious persons may use cannabis despite related problems if they believe such problems are common, and thus socially acceptable. Yet no known studies have examined the impact of beliefs regarding others' cannabis-related problems on one's own use-related problems.
METHOD: This study investigated the impact of beliefs about a close friend's experience with cannabis-related problems on the relationship between social anxiety and cannabis-related problems. The sample consisted of 158 (75% female) current (past-month) cannabis-using undergraduates.
RESULTS: Believing one's friend experienced more cannabis problems was related to experiencing more cannabis-related problems oneself. In fact, perceived friend's problems accounted for 40% of the unique variance in one's own cannabis problems. Descriptive norms (others' use) and injunctive norms (others' approval of risky use) were unrelated to the number of one's own problems. Social anxiety was related to experiencing more cannabis problems. This relation was moderated by perceived friend's problems such that greater social anxiety was related to more cannabis-related problems among participants who believed their friend experienced more cannabis-related problems. This was not the case among participants who believed their friend experienced fewer problems.
CONCLUSIONS: Normative beliefs regarding a close friend's cannabis problems were robustly and uniquely related to experiencing more cannabis-related impairment. Beliefs regarding friends' experience with cannabis-related problems may play an especially important role in the experience of cannabis-related problems among socially anxious users.