The interaction of distress tolerance and intolerance of uncertainty in the prediction of symptom reduction across CBT for social anxiety disorder.

Distress tolerance (DT) and intolerance of uncertainty (IU) have been identified as transdiagnostic processes that predict symptom severity across a range of distinct anxiety disorders. However, the joint effect of these two variables on therapeutic outcome has not yet been examined. It is possible that DT and IU may both impact on treatment response to cognitive-behavioural therapy (CBT) in clients with anxiety, as clients with weak DT and strong IU may be less likely to engage in exposure and cognitive restructuring tasks across treatment due to their associated distress. The purpose of this study was to examine the interaction of DT and IU as predictors of post-treatment symptom severity and treatment response to group CBT in participants with primary DSM-IV-TR diagnosed social anxiety disorder (SAD). Participants (N = 95) with SAD completed 12 weeks of manualized group CBT. Results of multilevel longitudinal analysis demonstrated an interaction effect, such that lower DT and higher IU predicted higher SAD symptom severity across the course of therapy. The findings are discussed in terms of clinical implications for the disorder-specific and transdiagnostic treatment of anxiety disorders.