Knowledge base Updated 2 November 2026 1 views

Motivational Interviewing

A collaborative conversational method for strengthening a person's own motivation for change, by drawing out and reinforcing the arguments for change that they make themselves rather than supplying them.

Definition

Motivational Interviewing (MI) is a way of talking about change that treats ambivalence as normal rather than as resistance.

The practitioner does not argue for change. They ask, reflect, and selectively reinforce change talk — the client's own statements about wanting, needing or being able to change. The technical claim is that people are more persuaded by what they hear themselves say than by what they are told.

History

William Miller described it in 1983, from observations in alcohol treatment where confrontational styles were standard and, as it turned out, predicted worse drinking outcomes.

Miller and Rollnick have revised the formulation repeatedly, most substantially in dropping the original stages-of-change framing, which was borrowed rather than intrinsic and has not held up well.

Theory

Four processes, roughly sequential and often revisited:

Engaging: establishing a working relationship.
Focusing: agreeing what the conversation is about.
Evoking: drawing out the person's own reasons for change.
Planning: moving to how, once willingness is there.

The mechanism with the best support is straightforward: practitioner behaviour affects the ratio of change talk to sustain talk, and that ratio predicts subsequent behaviour. Confrontation reliably increases sustain talk, which is why the confrontational style failed.

Research

Well supported in substance use, where the effects are modest but reliable and are achieved in far fewer sessions than most treatments require.

Evidence is more mixed in health behaviour change, medication adherence and diet. Effects tend to be small, and larger in trials with weaker comparison conditions.

The mechanism research is unusually good for a psychotherapy: the causal chain from practitioner behaviour to client language to outcome has been tested directly and largely holds.

Applications

Substance use, health behaviour change, medication adherence, offender work, and as a preface to other treatments when someone is ambivalent about starting.

It is also widely used badly. MI is a method, not a technique, and the most common failure is practitioners using reflective listening as a way to steer somebody toward a conclusion the practitioner has already reached.

Criticism

Effects are small. Reliable, but small, and they shrink against active comparisons.
Fidelity is rarely measured, so much of what is reported as MI in service settings is unlikely to be MI.
It is easy to learn badly. Training without coaching and feedback produces practitioners who believe they are doing MI and are not; this has been demonstrated repeatedly.
The ethics need thought. A method for strengthening motivation toward a particular change is a method of influence, and whose goal is being served is a real question in coerced settings.

References

Miller, W. R., & Rollnick, S. (2013). Motivational Interviewing: Helping People Change (3rd ed.). Guilford Press.
Magill, M., et al. (2018). A meta-analysis of motivational interviewing process. Journal of Consulting and Clinical Psychology, 86(2), 140-157.
Lundahl, B., et al. (2010). A meta-analysis of motivational interviewing. Research on Social Work Practice, 20(2), 137-160.
Miller, W. R., & Mount, K. A. (2001). A small study of training in motivational interviewing. Behavioural and Cognitive Psychotherapy, 29(4), 457-471.

Written for PsychologyOrbit and reviewed before publishing. It is a summary for professionals and students, not clinical guidance, and it is not a substitute for the primary sources listed above.