Motivational interviewing in substance use counseling

Motivational interviewing, often shortened to MI, is a way of talking with a person about change. The SAMHSA treatment guide TIP 35 quotes its developers, Miller and Rollnick, in describing it as a person-centered counseling style for addressing the common problem of ambivalence about change. Ambivalence means feeling two ways at once, for example wanting to cut down and also wanting to keep drinking.

What MI is used for

TIP 35, published by SAMHSA in 2019, says ambivalence about change is normal. It describes MI as a way to help people resolve that ambivalence and move toward changes in substance use by identifying and strengthening motivation that already exists. NIDA lists a closely related short-term approach, motivational enhancement therapy, also called motivational interviewing, that helps people build their resolve to quit using drugs or alcohol and assists them in setting and sticking with goals.

TIP 35 says motivational interventions can be used in brief interventions, in longer treatment and throughout the process of change. MI sits beside cognitive behavioral therapy and contingency management in NIDA's list of behavioral treatments.

The spirit of MI

TIP 35 states that the spirit of MI has four parts: partnership, acceptance, compassion and evocation. The guide says this spirit is the foundation of the approach and embodies person-centered counseling principles.

TIP 35 also takes a clear position on confrontation. It says resistance to change expresses ambivalence and is not a trait of the person, and that confrontational approaches increase resistance and discord in the counseling relationship. Motivational approaches instead explore ambivalence in a nonjudgmental and compassionate way.

How a conversation is shaped

The guide names four core skills, summarized by the acronym OARS, and says all four are used within each of the processes described below:

• Open questions
• Affirmations
• Reflective listening
• Summarization

In the updated version of MI described in TIP 35, four processes organize the work: engaging (building the relationship), focusing (agreeing on goals), evoking (using the core skills to move toward a specific change goal) and planning (the bridge to action). The original version had instead listed four principles: express empathy, develop discrepancy between goals and current behavior, roll with resistance, and support self-efficacy, meaning belief that change is possible. TIP 35 says these principles are still helpful but are folded into the processes.

The guide also separates "change talk", statements a person makes in favor of change, from "sustain talk", statements in favor of the status quo. The updated model puts new emphasis on evoking change talk and commitment to change.

What the research says

A 2023 Cochrane review, "Motivational interviewing for substance use reduction", looked at 93 randomized controlled trials with 22,776 participants. Its authors concluded that MI may reduce substance use compared with no intervention for a short period, and probably reduces use slightly compared with assessment and feedback at medium and long-term follow-up.

The reported numbers are small. Against no intervention, the review's standardized differences in substance use were 0.20 at one to four months and 0.12 at six to nine months. Against assessment and feedback alone, the difference was 0.24 at both six months and at 12 to 15 months, rated as moderate-certainty evidence. The review found no differences between MI and treatment as usual, or between MI and another active intervention.

The authors say they had moderate to no confidence in the evidence, so conclusions need caution and may change with future trials.

Limits

MI is best understood as a style of conversation and a means of building motivation, so the sources are cautious about what it can do alone. TIP 35 itself frames motivational approaches as a way to engage people and prepare them for further treatment, and the trial evidence reflects modest effects.

• Effects against no intervention or minimal feedback are small, and they shrink over longer follow-up.
• MI did not outperform other active treatments in the Cochrane review, so it is better seen as a way to engage someone than as a replacement for them.
• Certainty of the evidence was rated low or very low in most comparisons, often because of study limitations and inconsistent results.
• MI is a skill. TIP 35 recommends training and supervision that are competency based, so quality depends on the counselor.

For where MI can fit among the first steps toward care, see what happens when you ask for help.

Questions to ask a clinician

• Do you use motivational interviewing, and what training have you had in it?
• How would sessions focus on my own goals and mixed feelings?
• Would MI be a stand-alone approach for me, or combined with other treatment?
• How will we know if it is helping?