s / Drug and Alcohol Dependence 140 (2014) e86–e168 e89 Methods: Participants were 435 university students with past sixmonth cannabis use. Problemsweremeasuredwith the Rutgers Marijuana Problem Inventory.Motivationswere assessed using the Comprehensive Marijuana Motives Questionnaire. Results: Stepwise entry of all motives indicated that Coping, Social Anxiety, Boredom and Celebration motives were uniquely positively associated with cannabis-related problems (R2 changes = .02–.03, p’s < .01). Enjoyment, Celebration and Sleep motives were uniquely associated with higher frequency of use, whereas Experimentation motives were associated with less frequent use (R2 changes = .02–.09, p’s < .01). Frequency of use was positively associated with problems after controlling for motives (R2 change= .02, p< .01). Associations between problems and Coping, Celebration and Boredom motives were moderated by frequency of use; motives were more strongly associated with problems at higher frequency of use. This effect was most pronounced for Coping motives, with a stronger association among more frequent users (R2 = .27, p< .01), compared to less frequent users (R2 = .12, p< .01). Conclusions: These findings evidence the importance of motives in understanding problematic cannabis use. Moderation analyses revealed that associations between problems and Coping, Boredom and Celebration motives were stronger among frequent users. This pattern was particularly evident for Coping motives and suggests that individuals who engage in high levels of coping-motivated cannabis use may be at particularly high risk of encountering problems and thus represent a potentially important target group for interventions. Financial support: This research was supported by a grant to from the Social Sciences and Humanities Research Council of Canada to Zach Walsh. http://dx.doi.org/10.1016/j.drugalcdep.2014.02.258 Lack of association of cannabis use with opioid outcomes among opioid-dependent youth Kevin P. Hill 1,2, H.E. Bennett1, Margaret L. Griffin1,2, H.S. Connery1,2, G.M. Fitzmaurice1,2, Geetha Subramaniam3, George E. Woody4, Roger Weiss1,2 1 Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA, United States 2 Harvard Medical School, Boston, MA, United States 3 Center for Clinical Trials Network, National Institute on Drug Abuse, Bethesda, MD, United States 4 Department of Psychiatry, Treatment Research Institute, University of Pennsylvania, Philadelphia,