Examining within-person associations between alcohol and cannabis use and hooking up among adolescents and young adults in the United States.

Objective: This study examined daily associations between alcohol use, cannabis use, and simultaneous alcohol and cannabis/marijuana (SAM) use with the likelihood of hooking up (uncommitted sexual encounter that may or may not include intercourse).

Method: We used a longitudinal measurement burst ecological momentary assessment (EMA) design with 3-week EMA bursts with daily measurements repeated quarterly across 12 months. 1,009 (57 % female, Mean age = 20.00 [SD = 3.21]) Texan adolescents and young adults ages 15-25 participated in the study. Mixed effects logistic regression models were estimated using maximum likelihood estimation to evaluate the associations between substance use and hooking up.

Results: Within-person results indicated that participants were more likely to hook up on days with alcohol use and on days with cannabis use, but not on days with SAM use. Participants were also more likely to hook up on drinking days with higher-than-usual alcohol use. Between-person results indicated that participants who used alcohol more often or cannabis more often on average were more likely to hook up, and participants who tended to drink more on drinking days were more likely to hook up.

Conclusions: Given the significant daily-level associations between alcohol and cannabis use and hooking up behavior, public health initiatives should focus on developing interventions to reduce alcohol and cannabis use and promote safer hooking up behavior among adolescents and young adults.