Comparison of Motivational Interviewing with Acceptance and Commitment Therapy: A Conceptual and Clinical Review

Background: Motivational Interviewing (MI) and Acceptance and Commitment Therapy (ACT) are two emerging therapies that focus on commitment to behavior change. Aim: The aim was to provide the first systematic comparison of MI with ACT. Method: A systematic comparison was undertaken of MI and ACT at the conceptual level, with a focus on their philosophical and theoretical bases, and at the clinical level, with a focus on the therapeutic relationship, use of language in therapy, and use of values in therapy. Results: Conceptually, MI and ACT have distinct philosophical bases. MI's theoretical basis focuses on language content, whereas ACT's theoretical basis focuses on language process. Clinically, ACT and MI have distinct approaches to the therapeutic relationship, fundamentally different foci on client language, and different uses of client values to motivate behavior change. ACT, but not MI, directly targets the willingness to experience thoughts, feelings, and sensations. Conclusions: Despite their conceptual and clinical differences, MI and ACT are complementary interventions. Collaborations between MI and ACT researchers may yield fruitful cross-fertilization research on core processes and clinical outcomes.