Integrating Motivational Interviewing With Cognitive-Behavioral Therapy for Severe Generalized Anxiety Disorder: An Allegiance-Controlled Randomized Clinical Trial

Objective: Although integrating motivational interviewing (MI) and cognitive-behavioral therapy (CBT) has been recommended for treating anxiety, few well-controlled tests of such integration exist. Method: In the present randomized trial for severe generalized anxiety disorder (GAD), we compared the efficacy of 15 sessions of CBT alone (N = 43) versus 4 MI sessions followed by 11 CBT sessions integrated with MI to address client resistance/ambivalence (N = 42). Clients were adults, predominantly female and Caucasian, with a high rate of diagnostic comorbidity. To control for allegiance, therapists were nested within treatment group and supervised separately by experts in the respective treatments. Results: Piecewise multilevel models revealed no between-groups differences in outcomes from pre- to posttreatment; however, there were treatment effects over the follow-up period with MI-CBT clients demonstrating a steeper rate of worry decline (γ = −0.13, p = .03) and general distress reduction (γ = −0.12, p = .01) than CBT alone clients. Also, the odds of no longer meeting GAD diagnostic criteria were ∼5 times higher at 12-months for clients receiving MI-CBT compared with CBT alone. There were also twice as many dropouts in CBT alone compared with MI-CBT (23% vs. 10%); a difference that approached significance (p = .09). The treatments were competently delivered, and intraclass correlations revealed negligible between-therapist effects on the outcomes. Conclusions: The findings support the integration of MI with CBT for severe GAD and point to the importance of training therapists in appropriate responsivity to in-session markers of resistance and ambivalence. What is the public health significance of this article? This study highlights that assimilating MI strategies into CBT for GAD results in better longer-term outcomes than CBT alone. Thus, standard CBT for this debilitating condition can be improved by training therapists to notice markers of client resistance and ambivalence, and to shift in these moments to interventions marked by empathy, collaboration, and client-centeredness.