Therapist-Client Interactions in Motivational Interviewing: The Effect of Therapists' Utterances on Client Change Talk.

Aims: Motivational Interviewing is an effective treatment for a range of problematic behaviours, however, previous studies have revealed substantial variability in the effectiveness of therapists. Curiously, the specific behaviours which contribute to positive outcomes have rarely been studied. The aim of this study was to investigate hypothesised relationships between therapists' utterances and clients' change talk by analysing interactions sampled from the United Kingdom Alcohol Treatment Trial (UKATT).

Methods: This study comprised secondary analysis of process data and recordings selectively sampled from the UKATT database using sequential analyses of utterance categories, defined using the Motivational Interviewing Sequential Code for Observing Process Exchanges (MI-SCOPE). MI-SCOPE categories were modified on the basis of the existing literature. Observed and expected frequencies of change talk, transitional probabilities and their significance levels both immediately following therapists' statements (Lag 1), and after a delay (Lag 2) were calculated using the Generalised Sequential Querier (GSEQ) programme. Regression analyses were conducted using SPSS 21.0.

Results: In successful alcohol treatment sessions, therapists' open questions and complex reflections were significantly positively associated with client preparatory talk at Lag 1. Therapists' complex reflections were significantly positively associated with and predictive of strong client commitment talk at Lag 2.

Conclusions: The findings extend those of previous studies, suggesting that open questions and complex reflections play a central role in preparing clients for, and facilitating strong commitment to, behaviour change.