Development and differentiability of three brief interventions for risky alcohol use that include varying doses of motivational interviewing

BACKGROUND: While brief intervention (BI) for risky alcohol use generally yields positive effects among those identified by screening, effect sizes are small and there is unexplained heterogeneity in outcome. The heterogeneity may be related to differences in intervention style and content, including elements of motivational interviewing (MI). To date, it has been difficult to interpret the role of MI in BI and these gaps in knowledge interfere with efforts to train, disseminate and implement BI that retains and maximizes efficacy. This study sought to develop BI protocols with varying doses of MI and test their differentiability. Differentiable BI protocols could allow for future studies that prospectively evaluate the role MI plays in affecting BI outcome. METHODS: We developed three intervention protocols: brief advice, standard BI (NIAAA Clinician’s Guide), and MI-enhanced BI and administered them to 45 primary care patients who reported exceeding recommended drinking limits. We then rated the BI sessions for fidelity to the assigned protocol as well as MI consistency based on Motivational Interviewing Treatment Integrity (MITI) scale scores. The differentiability of BI protocols was determined by calculating fidelity to assigned protocols and comparing MITI scores using pairwise, Tukey-adjusted comparisons of least squares mean scores. RESULTS: High rates of fidelity to each protocol were achieved. The three BI protocols were also highly differentiable based on MITI scores. CONCLUSIONS: The three interventions can be used in future trials to prospectively examine the role MI has in determining BI outcome. Trial registration clinicaltrials.gov NCT02978027, retrospectively registered 11/28/16 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13722-017-0102-0) contains supplementary material, which is available to authorized users.