Cannabis and Alcohol Prepartying Among Young Adults: Daily-Level Associations with Cannabis Intoxication and Simultaneous Alcohol and Cannabis Use

OBJECTIVE: Prepartying is a high-risk context for alcohol use among young adults, yet little is known about cannabis use before social events. This study introduces cannabis prepartying and examines co-occurrence with alcohol prepartying, including simultaneous alcohol and cannabis (SAM) prepartying, and daily-level associations with cannabis intoxication and SAM use among young adults. METHOD: A longitudinal measurement burst ecological momentary assessment design was used. Participants ages 18-25 completed 3-week EMA periods repeated quarterly over 12 months. Analyses used two samples: participants reporting alcohol use on at least one sampled day (N = 507) and participants reporting cannabis use on at least one sampled day (N = 238). RESULTS: Cannabis prepartying occurred on 15.9% of all cannabis use days (37.4% of participants who used cannabis), whereas alcohol prepartying occurred on 13.6% of all alcohol use days (39.3% of participants who used alcohol). Cannabis prepartying was positively associated within- and between-person with hours high, subjective intoxication, and likelihood of SAM use. Alcohol prepartying was positively associated within- and between-person with SAM use before adjusting for drinks and hours high but only within-person after adjustment. CONCLUSIONS: Cannabis prepartying occurs among a substantial subset of young adults and represents a measurable social context that parallels alcohol prepartying. Cannabis prepartying co-occurs with alcohol use and is associated with greater likelihood of SAM use, along with longer duration of hours high and higher subjective intoxication. These associations were observed at both within- and between-person for cannabis prepartying, whereas alcohol prepartying was associated with SAM use at the within-person level only.