Egocentric Network Characteristics and Cannabis Use in a Sample of Young Adult Medical Cannabis Patients and Nonpatient Users.

Objective: Social factors play an important role in young adults' substance use behaviors, but little is known about how egocentric social network factors are related to young adults' cannabis use. Young adults also report medicinal and recreational uses of cannabis, which may alter the strength of these relationships. Therefore, medical cannabis patient status and medicinal/recreational orientation toward cannabis were examined as moderators of these relationships.
Method: Young adult medical cannabis patients ( n = 182) and nonpatient users ( n = 157) were surveyed in Los Angeles in 2015-2016 about their cannabis use, orientation (medicinal and/or recreational), and egocentric networks (cannabis use network size, social support network size, descriptive and injunctive norms). Regression models examined associations between network characteristics and past-90-day use and problematic use, and tested interactions between network characteristics and both patient status and cannabis use orientation.
Results: Only descriptive norms (adjusted incidence rate ratio [aIRR] = 1.19, 95% confidence interval [CI] [1.06, 1.33]) were associated with more frequent use, but not problematic use. Descriptive norms interacted with cannabis use orientation: descriptive norms were positively associated with cannabis use days among medicinally oriented users (aIRR = 1.22, 95% CI [1.02, 1.46]). However, this relationship was stronger for recreationally oriented users (aIRR = 1.62, 95% CI [1.31, 2.01]). No interactions were found predicting problematic use.
Conclusions: Descriptive cannabis use norms among one's personal network members are an important variable predicting young adults' cannabis use, but not problematic use. Perceived descriptive norms may be a stronger motivator to use for recreational users than medicinal users.