Motivational interviewing is designed to strengthen a person's commitment to changing their behavior by focusing on such factors as desire, self-efficacy, need, readiness, and reasons. In the original study, University of New Mexico researchers randomly assigned 152 outpatients and 56 inpatients to receive or not receive a single session of motivational interviewing as part of their drug abuse therapy.
The researchers assessed drug use at the pretreatment baseline and at 3, 6, 9, and 12 months following study entry. They found that adding a single session of motivational interviewing failed to have a positive effect on abstinence.
In a follow-up study, a psycholinguist watched videotapes of 84 persons undergoing motivational interviewing -- representing a subset of individuals from the earlier study -- and their therapists to analyze the language they used.
For the psycholinguistic analysis, each session was broken into four parts: motivational interviewing, assessment feedback, additional motivational interviewing, and developing a change plan. The researchers found that during the motivational interviewing segments, the study participants used language that showed a strong commitment to drug abstinence.
However, the analysis also revealed that individuals began "resisting," or using weaker language, when the therapist switched to giving assessment feedback. There was also a precipitous decline in commitment language when the therapist pressed for a plan to initiate behavior changes.
The finding from the first study -- the failure of motivational interviewing to have a positive impact on drug use behaviors -- was unexpected because previous assessments had shown that the technique improved treatment retention, adherence, and outcome. Results of the second study suggest that therapists should modify manual-guided motivational interviewing techniques when faced with individuals whose language, especially during assessment feedback, begins to reflect a decline in their initial desire to reduce drug use. By pressing for change before a person is ready, the therapist can undermine the existing motivation for behavior change.
Dr. William Miller and his colleagues published these NIDA-funded studies in the August 2003 and October 2003 issues of the Journal of Consulting and Clinical Psychology.
