Effects of optimism and stage of change on alcohol use and problems among sexual minority men with HIV participating in a brief motivational interviewing intervention.

Introduction: Disseminating effective alcohol interventions for sexual minority men (SMM) with HIV remains a crucial public health endeavor. Motivational interviewing (MI) interventions are an established approach to reducing alcohol use, yet more research is needed to determine predictors of MI treatment outcomes and underlying mechanisms related to sustained behavior change among SMM with HIV. This pre-registered secondary analysis tested whether action-related stage of change mediated effects of a MI intervention on future alcohol use and problems among SMM with HIV, and whether individual differences in trait optimism moderated these associations.

Methods: SMM with HIV who engaged in frequent alcohol use (N = 180) were randomized to MI or assessment-only treatment as usual (TAU). Participants completed a semi-structured Timeline Follow-Back interview to measure past-month alcohol use as well as self-reports assessing stage of change, trait optimism, and alcohol problems at baseline and 3- and 12-months post-baseline.

Results: Structural equation models controlling for baseline alcohol use and stage of change indicated that 3-month action significantly mediated effects of MI on 12-month drinks per week. Likewise, the indirect effect of 3-month action was moderated by higher levels of trait optimism. When employment status, education level, and annual family/household income were included as covariates in the model, being employed significantly predicted 12-month alcohol use, and mediation and moderated mediation effects were no longer statistically significant. Stage of change did not mediate effects of MI on 12-month alcohol problems, and this indirect effect was not moderated by trait optimism.

Conclusions: The present study provides further evidence supporting action-related stage of change as a mechanism linking MI to alcohol use reductions. Results demonstrated that SMM with HIV who were more optimistic tended to take more action towards reducing their alcohol use and suggest that MI-based interventions may benefit from integrating components aimed at augmenting patients' optimism. Yet, covarying for current economic status substantially impacted findings and underscores the need to critically consider how broader socioecological contexts can impact treatment outcomes.