The Role of Marijuana Use in Brief Motivational Intervention With Young Adult Drinkers Treated in an Emergency Department* MOLLY MAGILL, P.D.,fj NANCY P. BARNETT, PH.D., TIMOTHY R. APODACA, PH.D., DAMARIS J. ROHSENOW, PH.D.,f AND PETER M. MONTI, PH.D.t Centerfbr Alcohol and Addiction Studies, Brown University, Box G-S121-4, Providence, Rhode Island 02912 ABSTRACT. Objective: The aim of this research was to study mari- juana use, associated risks, and response to brief motivational interven- tion among young adult drinkers treated in an emergency department. Method: Study participants (N = 215; ages 18-24) were in a randomized controlled trial for alcohol use that compared motivational interviewing with personalized feedback (MI) with personalized feedback only. Past- month marijuana users were compared with nonusers on demographics, readiness, self-efficacy, and behavioral risk variables. Marijuana use was examined as a potential moderator of alcohol outcomes. Whether marijuana use alone or combined marijuana and alcohol use would be reduced as a result of brief intervention for alcohol was examined at 6 and 12 months. Results: Current marijuana users were younger, were more likely to be white, and reported more alcohol use, other illicit drug use, and more alcohol-related consequences than nonmarijuana users. Marijuana use at baseline did not moderate response to brief alcohol treatment. Marijuana use declined from baseline to 6 months for both treatment groups, but only MI participants continued to reduce their use of marijuana from 6- to 12-month follow-up. Reductions in number of days of use of marijuana with alcohol appeared to be primarily a function of decreased alcohol use. Conclusions: Young adult drinkers reporting current marijuana use are at generally higher risk but responded to brief alcohol treatment by reducing alcohol and marijuana use. (J. Stud. Alco- hol Drugs 70: 409-413, 2009) R ATES OF MARIJUANA AND ALCOHOL USE are highest among older adolescents and young adults (Substance Abuse and Mental Health Services Adminis- tration, 2007b), and the emergency department (ED) is a medical setting where young adults are often seen when experiencing substance-related events such as illness or injury. Marijuana use occurs in approximately one third of drug-related ED admissions with rates of marijuana-related events highest among 18- to 24-year-olds (Substance Abuse and Mental Health Services Administration, 2007a). High rates of marijuana use are found in general samples of ED patients (Rockett et al., 2006; Soderstrom et al., 1988) and in adult ED patients treated for alcohol problems (Woolard et al., 2003); and greater injury-related risk has been shown among patients using both alcohol and marijuana (Soder- strom et al., 1988; Woolard et al., 2003). Received: July 29, 2008. Revision: November 26, 2008. *This research was supported by National Institute on Alcohol Abuse and Alcoholism research grant AA09892 and training grant T32 AA07459, and a Department of Veterans Affairs Senior Career Research Scientist Award to Peter M. Monti. t Correspondence may be sent to Molly Magill at the above address or via email at: molly-magill@brown.edu. Damaris J. Rohsenow and Peter M. Monti are also with the Providence VA Medical Center, Providence, RI. Medical settings provide an opportunity for screening (Chung et al., 2003) and early intervention with non-treat- ment-seeking alcohol and marijuana users (Degutis, 2003). ED studies of brief motivational interventions (BMIs) for alcohol have demonstrated positive outcomes with older ado- lescent and young adult samples (Monti et al., 1999, 2007). Although studies have effectively targeted multiple risk behaviors for injury among adolescents in the ED (Johnston et al., 2002), we found no published studies that targeted multiple substances with older adolescents or young adults in ED settings. However, BMI has reduced both alcohol and marijuana use among adult ED patients more than standard services (Woolard et al., 2008). A few studies have targeted multiple substances with college students, and a recent study examined adolescent substance use in a general medi- cal setting. D'Amico and colleagues (2008) found greater reduction of marijuana use in a BMI compared with usual services among at-risk adolescents recruited in a primary care clinic. BMI and written personalized feedback were effective in reducing alcohol, nicotine, and marijuana use with mandated college students (White et al., 2006, 2007), and non-help-seeking college students decreased alcohol, nicotine, and marijuana use more after BMI than education- as-usual comparisons (McCambridge and Strang, 2004). The studies reviewed targeted substances other than al- cohol, but it is possible that subjects will decrease drug use 409