Abstract

Intolerance of uncertainty (IU) is a dispositional characteristic that arises from negative beliefs about uncertainty and its implications (Koerner & Dugas, 2006). IU is an important factor in both the development and maintenance of generalized anxiety disorder (GAD; APA, 2013). A cognitive-behavioural treatment (CBT) for GAD that targets IU and additional factors has shown robust efficacy across five randomized controlled trials. IU is a key cognitive mechanism in this treatment, as reductions in IU precede (Dugas & Ladouceur, 2000; Goldman, Dugas, Sexton, & Gervais, 2007) and mediate reductions in GAD symptoms (Donegan et al., 2010). Despite these encouraging results, approximately 20-30% of individuals do not achieve full GAD remission by posttreatment. Non-remitted individuals continue to endorse elevated IU. Moreover, established CBT protocols for GAD are often lengthy and complex, involving multiple therapeutic techniques. Thus, GAD treatment development and evaluation must consider parsimony and efficiency in addition to efficacy. To that end, we developed a novel, focused CBT protocol that targets IU exclusively via behavioural experiments. This cognitive-behavioural technique is an experiential method of testing idiosyncratic beliefs (here, beliefs about uncertainty). Participants with a primary diagnosis of GAD (N = 7) completed 12 sessions of this CBT protocol with a licensed clinical psychologist at a local Montreal hospital. Treatment consisted of three components: (1) psychoeducation and uncertainty awareness training; (2) behavioural experiments targeting beliefs about uncertainty, and (3) relapse prevention. Our results suggest that this CBT protocol produces substantial reductions in GAD symptomatology, IU, and general psychopathology by posttreatment. These changes were generally maintained across a 6-month follow-up period, with some deterioration in safety behaviours, general anxiety, and depression. The majority of participants (6/7) demonstrated moderate to high end-state functioning from posttreatment to 6-month follow-up. Additionally, we examined rapid, non-linear changes in IU, worry, and safety behaviours between treatment sessions. Results indicated that sudden gains in IU tended to occur first and that sudden gains occurring early in treatment were associated with improved long-term treatment outcomes. Overall, our findings suggest that the systematic application of behavioural experiments alone may provide substantial reductions in GAD symptoms and IU.