Do brief motivational interventions increase motivation for change in drinking among college students? A meta-analysis of individual participant data

Brief Motivational Interventions (BMIs) have been identified as one of the most effective individually focused alcohol intervention strategies for college students in the United States. Despite the central role of motivation for change in BMIs, whether BMIs increase motivation for change has rarely been investigated. The current study conducted a meta-analysis of individual participant data (IPD; 15 studies, N = 5,903) from Project INTEGRATE (Mun et al., 2015) to examine whether BMIs increase motivation for change in drinking. Different measures and responses used in the original trials were harmonized across studies, and effect size estimates were derived from a model that adjusted for baseline motivation and demographic variables for each study (step 1) and subsequently combined in a random-effects meta-analysis model (step 2). After adjustment for baseline levels of motivation level and demographic variables, the intervention effects of BMIs on motivation for change was not statistically significant (standard mean difference [SMD]: 0.026, 95% CI: [-0.001, 0.053], p = .06, k = 19). Subsequent metaregression analyses among BMI subtypes indicated that the intervention effect did not differ between individually delivered motivational interviewing with personalized feedback (MI+PF), stand-alone personalized feedback (PF), and group-based motivational interviewing (GMI). Among all BMI subtypes, only GMI had a statistically significant intervention effect on motivation compared to controls (SMD: 0.055, 95% CI: [0.007, 0.103], p = .025, k = 5). Within the first three months post-intervention, there was a decrease in SMD of 0.05 (95% CI: [0.01, 0.08]) in motivation per month. However, no statistically significant difference in the intervention effects was found between studies with short-term vs. long-term follow-up. Although the results from the current study do not support the hypothesis that BMIs improve motivation for change, the evidence as a whole suggests ways in which motivation may be improved following intervention and can be tested in future studies.