Motivational interviewing in smoking cessation : effectiveness, active components, and acquisition of counsellor skills

Sammanfattning: Aim: The overall aims of the present thesis are to investigate the effectiveness and active components of Motivational Interviewing (MI) in telephone-based smoking cessation treatment, and to explore the acquisition of MI skills of smoking cessation counsellors. Method: The setting of all included studies was the Swedish National Tobacco Quitline (SNTQ). In evaluating the effectiveness of MI (Study I), clients calling the SNTQ between September 2005 and October 2006 were allocated to receive either treatment as usual (TAU) or TAU with added MI. The primary outcome measures were self-reported 7-day point prevalence abstinence and 6-month continuous abstinence at 12-month follow-up. To examine the predictive power of the hypothesised active MI components (Study II and III), 106 audio-recorded treatment sessions were analysed using the Motivational Interviewing Sequential Code for Observing Process Exchanges (MI-SCOPE) Coder's manual and the Motivational Interviewing Treatment Integrity (MITI) manual, version 3.1. The SNTQ counsellors’ acquisition and retention of MI skills (Study IV) were assessed using the MITI manual, version 3.0, over 11 assessment periods at fixed intervals over two and a half years (September 2004 to February 2007). Results: At 12-month follow-up, 19% of the clients allocated to MI-trained counsellors reported 6-month continuous abstinence, versus 14% of the TAU clients (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.00–2.19; p < .05). The counsellors’ relational skills (demonstrating MI spirit) were positively associated with smoking outcome among unmotivated SNTQ clients (i.e., clients not expressing Activation utterances favouring change). The counsellors’ technical MI skills (e.g., questions and reflections favouring change) were associated with in-session client language, while in-session client language was, in turn, found to predict smoking outcome. For each expressed Activation utterance favouring abstinence, clients were 73% more likely to stop smoking (OR 1.73, 95% CI 1.08-2.76, p < .05). Conversely, for each expressed Desire or Need utterance favouring continued smoking, clients were 80% less likely to stop smoking (OR 0.20, 95% CI 0.04; 0.97, p < .05). Mediation analysis also revealed that this client language mediated the relationship between counsellors’ reflections favouring continued smoking and smoking status at follow-up. In Study IV, we observed notable smoking cessation counsellor difficulties in acquiring MI skill as well as great variation in MI skill between counsellors and in counsellor performance over time. Conclusions: Integrating MI into a cognitive behavioural therapy-based smoking cessation protocol in an ordinary clinical setting increased clients’ 6-month continuous abstinence rates by 5%. Consistent with MI theory, the findings suggest that smoking cessation counsellors should cultivate client Activation utterances favouring abstinence and soften client utterances expressing Desire or perceived Need to smoke in order to contribute to higher rates of treatment success. However, MI implementation was only partly successful, despite an extensive MI training, including continual supervision and systematic feedback on counsellors’ clinical practice.