Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Although empirical investigations strongly support the use of Motivational Interviewing (MI) as a prelude to further treatment, the underlying mechanisms of MI that lead to change remain to be clarified. In a recent randomized controlled trial, Westra et al. (2009) demonstrated that adding MI pretreatment to Cognitive Behavioural Therapy (CBT) for Generalized Anxiety Disorder (GAD), compared to CBT without a pretreatment, was substantially and specifically helpful in reducing worry for patients with high symptom severity. Patient resistance to treatment was found to directly mediate the relationship between getting MI pretreatment or not and outcome. The findings suggest that patient resistance can be used as an outcome measure for the efficacy of MI, opening up new possibilities to examine MI mechanisms. Although studies have demonstrated that patient resistance is a critical predictor of treatment outcome, this central component of MI is currently understudied. The present study addresses this important gap by empirically investigating mechanisms through which MI leads to reduced resistance and better outcomes. The Motivational Interviewing Skill Code (Miller et al., 2003) will be used to code videotaped sessions of MI for patients who received MI prior to CBT in the Westra et al. trial. Therapists will be rated on dimensions of MI-consistent techniques and interpersonal skill, and patient responses will be rated for talk for or against change, to examine the extent to which hypothesized mechanisms of change in MI are predictive of patient resistance in subsequent therapy. The present study has very important implications for understanding specific mechanisms of change in MI, which can explain how the addition of MI to CBT might be effective in enhancing patient response to subsequent treatment. Such knowledge can enhance clinical care by suggesting methods for managing resistance and improving treatment outcomes for patients with high symptom severity GAD.