Mechanisms of Motivational Interviewing: a Conceptual Framework to Guide Practice and Research

Reviews of the motivational interviewing (MI) training literature demonstrate MI is a nuanced skill set that takes carefully planned didactic training, application of skills in context-specific practice settings, and ongoing support to promote reflective practice and sustained proficiency. Despite the robust knowledge base related to training and how MI works to achieve favorable outcomes, these two literature bases are not well integrated. In an effort to inform and guide future research, we propose the mechanisms of motivational interviewing (MMI) conceptual framework, which expands upon previous work. Specifically, the framework adds training as an ongoing process consistent with Bennett-Levy’s (Behav Cogn Psychother 34:57–78, 2006) model of skill development and acquisition to the existing two-path framework that helps us to understand how MI works to achieve its desired effects (Magill et al., J Consult Clin Psychol 82:973–983, 2014). Herein, we describe measures used to evaluate the mechanisms within the four MMI framework links: initial training to competency, competency to proficiency, proficiency to talk about change, and talk about change to behavior change. Next, we synthesize the literature associated with each of the mechanisms of the MMI. We conclude by discussing implications for practice and research. This framework offers a more complete path structure to understand the mechanisms of change associated with MI that could improve our understanding of inconsistent effect sizes observed across prior trials evaluating MI effectiveness.