The prospective interactive effects of alcohol expectancies and subjective response on future drinking behavior.

Although alcohol expectancies and subjective response are independent predictors of drinking, social–cognitive theory suggests that expectancies may distort one’s subjective response, creating discrepancies between expected and actual alcohol effects. A recent cross-sectional study found that unmet expectancies (using difference scores) were associated with heavier drinking. However, cross-sectional data cannot establish temporal precedence, and using difference scores ignores important conditional main effects. As such, the current study sought to evaluate how expectancy-subjective response discrepancies predict future drinking using prospective data and an interaction approach. Participants (N = 258) were randomly assigned to consume alcohol (target BAC = .08%) within a placebo-controlled alcohol administration session. Alcohol expectancies and subjective response were assessed across the full valence by arousal affective space using parallel measures. Results indicated a significant high arousal positive (HIGH+) interaction, such that, as HIGH+ expectancies increased, individuals at low and mean levels of HIGH+ subjective response drank more heavily 12 months later. There was also a significant high arousal negative (HIGH–) interaction with a similar pattern of moderated effects. No interactions were found for low arousal effects. These results indicate that individuals with unmet HIGH+ and HIGH– expectancies drink more heavily 12 months later, controlling for prior drinking. This suggests that clinicians may consider recommending specific interventions (e.g., expectancy challenges vs. pharmacotherapy) based upon an individual’s levels of expectancies and subjective response to optimize intervention efficacy.