Momentary patterns of alcohol and cannabis co-use in college students: Assessing the temporal association with anxiety.

Using ecological momentary assessment (EMA), we assessed momentary patterns of alcohol and cannabis co-use in college students and whether state-level and baseline reports of anxiety varied based on type of substance(s) consumed. Students (=109) reporting regular cannabis use completed a baseline assessment and two-week signal-contingent EMA, with three random prompts/day. At each EMA instance, we categorized instances of substance "usage" as: 1) no use, 2) cannabis-only, 3) alcohol-only, or 4) co-use of alcohol and cannabis (i.e., reports of alcohol and cannabis use within the same prompt). Using temporal sequenced data, we explored how state-level anxiety varied before and after usage type using multiple multilevel structural equation models (MSEMs) and whether baseline factors (general anxiety, social anxiety, and sex) influenced the relation between usage type and state-level anxiety. Participants were 63.3% White, 58.7% female, used cannabis near-daily, and commonly reported co-use. Models examining whether usage type predicted subsequent state-level anxiety were predominantly significant, with the majority of relationships being more pronounced for participants with higher baseline general anxiety. In examining whether momentary state-level anxiety predicted usage type, in instances when participants reported higher levels of momentary anxiety, they were more likely to report no use compared to co-use and cannabis-only, with sex moderating some of the relationships. Social anxiety did not moderate any of the within-person associations between state-level anxiety and usage type. This study provides preliminary evidence that report of momentary anxiety varies based on substance type. Future research is needed to establish co-use related synergistic effects and correlates.