Simultaneous Alcohol and Marijuana Use Versus Alcohol Use Only on Protective Behavioral Strategies: The Moderating Influences of Coping and Enhancement Motives

Simultaneous alcohol and marijuana (SAM) use is elevated among college students. Protective behavioral strategies (PBS) could help limit harms from SAM use among college students, but utilization of PBS with SAM use is understudied. The current study sought to investigate PBS endorsement differences between students with past-month SAM use and alcohol-only use, as well as the moderating roles of motives and past-month alcohol use quantity. Participants were 3,281 undergraduate college students recruited from several universities throughout the U.S., who reported past-month alcohol use (Mage = 19.43, 63.8% White, 72.6% cisgender woman). Participants completed a series of online, self-report measures. Neither positive effects nor coping motives moderated the relationship between SAM use and PBS (ps = 0.716, 0.711). Coping motives did not moderate alcohol use and PBS (p = 0.108), yet there was a significant, negative interaction between enhancement movies and alcohol use on PBS (B = -0.07, SE = 0.02, p = 0.001, 95% CI [-0.12, -0.03]) such that more alcohol use and greater endorsement of enhancement motives indicated fewer PBS. Alcohol use quantity did not moderate either SAM use or alcohol use only on PBS (ps = 0.092, 0.711). Coping and positive effect motives did not moderate the relationship between SAM use and PBS, but enhancement motives moderated the relationship of the alcohol use only group and PBS. These findings suggest the importance of substance use motives on willingness to engage in PBS and illuminate a vulnerable group for negative alcohol use outcomes.