From counselor skill to decreased marijuana use: does change talk matter?

Client language about change, or change talk, is hypothesized to mediate the relationship between counselor fidelity in motivational interviewing (MI) and drug use outcomes. To investigate this causal chain, this study used data from an MI booster delivered to alternative high school students immediately after a universal classroom-based drug abuse prevention program. One hundred and seventy audio-recorded MI sessions about substance use were coded using the motivational interviewing skill code 2.5. Structural equation modeling showed that percentage of change talk on the part of the client mediated three of the four relationships between MI quality indicators and marijuana outcomes, while percentage of reflections of change talk showed a main effect of counselor skill on marijuana outcomes. Findings support change talk as an active ingredient of MI and provide new empirical support for the micro-skills of MI.