Session: Simultaneous Use of Marijuana with Other Substances: An Emerging Target for Prevention (Society for Prevention Research 27th Annual Meeting)

Introduction: Corresponding to recent changes in laws regarding recreational marijuana, there has been a lessening of risk perceptions and more positive norms regarding marijuana use. These shifts in perceptions have been accompanied by increases in the use of marijuana and increases in using marijuana simultaneously (“so that the effects overlap”) with other substances. Simultaneous use incurs more negative consequences than using marijuana alone. Nevertheless, little is known about simultaneous substance use to inform prevention programs for emerging adults, the age group with the highest rates of marijuana use and cannabis use disorder. This symposium will examine patterns, risk factors, perceived norms, and consequences associated with simultaneous use of marijuana with other substances during emerging adulthood. Presentation 1: The first paper uses a sample of college students to examine patterns of simultaneous alcohol and marijuana (SAM) use and normative influences on use. SAM users perceived higher rates of SAM use by same-gender peers and close friends, compared to other students, and higher perceived norms were related to more frequent SAM use and related negative consequences. Personalized normative feedback may be an efficacious prevention approach. Presentation 2: The second paper examines differences in alcohol and marijuana use, consequences and motives among college students who engage in nonmedical use of prescription stimulants (NPS) simultaneously with alcohol and marijuana, those who engage in NPS without simultaneous use, and NPS abstainers. The heaviest rates of alcohol and marijuana use and negative consequences were found for students who engaged in simultaneous NPS, followed by those who engaged in NPS but not simultaneously, and those who did not engage in NPS. In addition, those who engaged in simultaneous NPS reported the highest motivations for using alcohol and marijuana to increase the effects of other drugs. Interventions that focus on drug interactions and perceived norms may reduce simultaneous NPS. Presentation 3: The third paper compares alcohol only users, co-users of alcohol and marijuana who do not use them simultaneously, and SAM users in terms of risky driving perceptions and behaviors. SAM users reported the highest levels of general risky driving as well as driving under the influence of alcohol and marijuana and the lowest risk perceptions. Preventive interventions that address driving risks related to simultaneous and single use of alcohol and marijuana are needed during emerging adulthood. Discussion: The discussant from NIDA will discuss the implications of these findings for prevention approaches for emerging adults as well as for policy.