Understanding intolerance of uncertainty in social anxiety disorder: Associations with symptom severity, functioning, and time course.

Intolerance of uncertainty (IU) is an individual difference dimension reflecting negative cognitive, emotional, and behavioral responses to uncertainty. IU is an important etiological and maintaining mechanism of internalizing psychopathology, including social anxiety disorder (SAD). The current study aimed to further understand the relationship between IU and SAD symptom severity, distress, and functioning as well as the predictive power of IU for SAD symptoms and functioning over time. Consistent with our hypotheses, we found that IU was greater in individuals with a lifetime diagnosis of SAD (n = 136) than individuals who never met criteria for SAD (n = 572). We also found that amongst individuals with a lifetime diagnosis of SAD, greater IU was associated with more severe SAD symptoms, more SAD-related distress and impairment, and worse functioning, even after covarying for comorbid psychiatric conditions, highlighting the specificity of effects to SAD. Contrary to our hypothesis, IU did not differ between those with current versus remitted SAD. Baseline IU continued to predict SAD symptoms and disability at follow-up, but not a change in symptoms or disability. Finally, IU and SAD symptoms both decreased during follow-up for those with a lifetime SAD diagnosis, but these changes were not correlated, suggesting that changes in IU may not track with changes in SAD symptoms. These findings suggest that intolerance of uncertainty may identify a more severe subtype of individuals with SAD and needs to be addressed in SAD treatments.