Rates, Consequences, and Motives Surrounding Simultaneous Use of Prescription Stimulant Medication with Alcohol and Marijuana

Introduction: Nonmedical use of prescription stimulants (NPS) is a growing problem on college campuses. Prevalence estimates of lifetime NPS are wide ranging, with studies reporting between 5%-43% of college students engaging in NPS. Previous research demonstrates a strong link between NPS and other substance use, particularly alcohol and marijuana use. Moreover, simultaneous NPS with other substances has also become an increasing concern. Given the high rates of NPS and simultaneous NPS with other substances, research examining substance use patterns and motives for use is warranted to help inform the design of prevention and intervention approaches. This study evaluated group differences in alcohol and marijuana use patterns and consequences as well as motivations among college students: a) with no NPS history (No NPS); b) who engaged in NPS with no simultaneous use (Non-Sim NPS); and c) who engaged in simultaneous NPS with alcohol and/or marijuana (Sim NPS). Methods: Participants included 1,390 students from three universities who reported using marijuana and alcohol in the past year. Univariate analyses of covariance (ANCOVAs) were conducted to examine group differences in alcohol use (average drinks consumed per week, past 30-day number of heavy drinking episodes, past 3-month frequency of alcohol use) and related negative consequences, marijuana use (past 3-month frequency and average hours high) and related negative consequences, and motives for using each substance among students in the three groups. Results: Overall, 32.8% reported lifetime NPS, of which 26.5% reported engaging in NPS simultaneously with alcohol and 20.6% with marijuana. Significant group differences for all drinking and marijuana outcomes were found, with the heaviest rates of use among the Sim NPS group, followed by the Non-Sim NPS group, and then the No NPS group. Moreover, the Sim NPS group reported greater motives for using alcohol and marijuana to alter the effects of other substances. Conclusions: Considering that the context of substance use is essential in a clinical setting, these findings have important implications for screening efforts in health and counseling settings. College students who engage in simultaneous NPS with alcohol and marijuana are a high-risk group that could warrant attention in college substance use prevention and intervention programs. Prevention messaging could highlight the dangers of drug interactions and incorporate social norms messages targeting normative perceptions regarding NPS and simultaneous NPS among college students.