Category: Adult Anxiety
Introduction: Distress tolerance (DT), or the ability to tolerate aversive states (Simons & Gaher, 2005), and intolerance of uncertainty (IU), or the tendency to react negatively to situations that involve a degree of uncertainty (Ladouceur, Gosselin, & Dugas, 2000), have both been linked to symptom severity across mood and anxiety disorders. Less is known about how these two variables interact in order to predict symptom severity over the course of cognitive behavioural therapy (CBT). Greater knowledge about predictors of post-treatment symptom severity can be used to guide future treatment adaptations. The purpose of this study was to examine the interaction of DT and IU in the prediction of symptom severity over the course of CBT for social anxiety disorder (SAD).
Method: Participants with social anxiety disorder based on SCID-IV screening (N = 95) completed 12 weeks of CBT for SAD at a university-affiliated outpatient anxiety disorders centre. Pre-treatment measures included the Distress Tolerance Scale (DTS) and the Intolerance of Uncertainty Scale -12 (IUS-12). Participants completed the Social Interaction Anxiety Scale (SIAS) and the Social Phobia Scale (SPS) at sessions 1, 4, 8, and end of treatment.
Results: Multilevel longitudinal analysis was used to examine the effect of DT and IU on symptom severity over treatment as well as interaction effects between the variables. Lower DTS scores significantly predicted greater symptom severity across the course of therapy on both the SIAS (B = -0.30, p = 0.004, 95% CI [-0.50, -0.10]) and SPS (B = -0.47, p < 0.001, 95% CI [-0.71, -0.23]), as did higher IUS-12 scores (SIAS: B = 0.53, p < 0.001, 95% CI [0.34, 0.73]; SPS: B = 0.56, p < 0.001, 95% CI [0.30, 0.81]). Furthermore, DT significantly moderated the relationship between IU and symptom severity, such that participants with low DT and high IU were likely to have higher social anxiety symptoms (SIAS: B = -0.03, p < 0.001, 95% CI [-0.04, -0.01]; SPS: B=-0.03, p = 0.01, 95% CI [-0.04, -0.01]).
Discussion: Both DT and IU significantly predict symptom severity throughout treatment. Distress tolerance significantly moderated the relationship between IU and symptom severity. Results will be discussed in context of potential research and clinical implications.