Abstract

ABSTRACT
CBT and Interpretation Bias Modification for Generalized Anxiety Disorder: Examining the Roles of Intolerance of Uncertainty and Interpretation Bias in Symptom Reduction

Eleanor Donegan, Ph.D.
Concordia University, 2016

Generalized Anxiety Disorder (GAD) is characterized by excessive worry and anxiety (APA, 2013). Although cognitive behaviour therapy (CBT) is efficacious, 20-50% of individuals with GAD continue to meet diagnostic criteria following treatment (Hanrahan et al., 2013). To improve outcomes, it is essential that we develop a better understanding of the factors involved in symptom reduction and ensure that these factors are targeted effectively. Two factors that are associated with excessive worry and anxiety are intolerance of uncertainty (IU) and negative interpretation bias (Ladouceur et al., 2000; Rosen & Knaüper, 2009), both of which have been proposed to play a role in the maintenance of GAD symptoms (Hayes & Hirsch, 2007; Koerner & Dugas, 2006). In this program of research, the first goal was to examine the impact of an IU-focused CBT (Dugas & Ladouceur, 2000) on IU and negative interpretation bias and to determine whether these factors played a role in symptom reduction. In Study 1, 80 adults completed CBT for GAD. By post-treatment, CBT was associated with reductions in GAD symptoms, IU and negative interpretation bias. Moreover, reductions in negative interpretation bias predicted reductions in GAD symptoms and this effect was partially mediated by reductions in IU. Cognitive bias modification programs (CBM-I) have also been developed to target interpretation bias, primarily among socially anxious individuals, and have been proposed as low-cost alternatives to CBT (Amir & Taylor, 2012). The second goal in this program of research was to validate a new CBM-I program designed to target interpretation bias in GAD worry domains. In Study 2, participants who completed CBM-I (n = 16) exhibited greater reductions in negative interpretation bias than participants in an interpretation control condition (n = 14). However, CBM-I training did not lead to anticipated reductions in worry or anxiety. Overall, this program of research provided further support for an IU-focused CBT and insight into change processes during treatment. Although the CBM-I program examined here cannot yet be recommended as a stand-alone intervention, other clinical uses of CBM-I are discussed, including the possibility of implementing CBM-I as an adjunct intervention to enhance the efficacy of CBT.