Real-time discrepancies between simultaneous alcohol and cannabis expectancies and subjective responses

Simultaneous alcohol and cannabis use is common, prevalent, and risky. Ecological momentary assessment (EMA) research suggests that simultaneous use is associated with increased positive subjective responses. However, research has yet to examine how often, and what happens when, subjective responses to simultaneous use are discrepant from one's expectations.

Young adults who reported simultaneous use during acute drinking reports (N = 71) completed 21 days of ecological momentary assessment. Individuals reported their simultaneous use expectancies at baseline and their subjective stimulation and relaxation during acute use episodes - for this study, moments when an individual reported simultaneous use were retained. Two-level multilevel models tested (1) the extent to which one's simultaneous use expectancies aligned with their acute stimulation/relaxation during simultaneous use moments and (2) whether feeling higher stimulation/relaxation than expected were associated with alcohol and cannabis use cravings.

Individuals with higher stimulant simultaneous use expectancies experienced higher levels of stimulant subjective effects during simultaneous use moments. Similarly, individuals with higher relaxation simultaneous use expectancies experienced higher levels of subjective relaxation during simultaneous use moments. Experiencing more stimulant subjective effects than expected from simultaneous use was associated with both increased alcohol craving and cannabis craving. However, greater-than-expected stimulant subjective effects from simultaneous use had a stronger impact on alcohol versus cannabis craving.

Simultaneous use expectancies were modestly associated with subjective responses during simultaneous use moments, and experiencing greater-than-expected stimulation motivated continued use, particularly for alcohol. When assessing subjective response to simultaneous use, it is important to take expectancies into consideration.