Abstract
Intolerance of uncertainty (IU) has contributed to our understanding of excessive worry and adult anxiety disorders, but there is a paucity of research on IU in child samples. This gap is due to the absence of a psychometrically sound measure of IU in youth. The present study adapted parallel child- and parent-report forms of the Intolerance of Uncertainty Scale (IUS) and examined the internal consistency, convergent validity, and classification properties of these forms in youth aged 7-17 (M = 11.6 years, SD = 2.6). Participating youth (N = 197; 100 girls, 97 boys) either met diagnostic criteria for an anxiety disorder (n = 73) or were nonreferred community participants (n = 124). The child-report form (i.e., IUS for Children, or IUSC), and to a lesser extent the parent-report form, demonstrated strong internal consistency and convergent validity, evidenced by significant associations with anxiety and worry (and reassurance-seeking in the case of the child-report form). Children diagnosed with anxiety disorders scored higher than nonreferred community youth on both forms. Receiver operating characteristic (ROC) analysis demonstrated acceptable overall utility in distinguishing the 2 groups of youth. Findings provide preliminary support for use of the IUSC for continuous measurement of children's ability to tolerate uncertainty.