Intolerance of uncertainty in youth: Psychometrics of the Intolerance of Uncertainty Index-A for Children.

Intolerance of uncertainty (IU) is a cognitive vulnerability for pathological anxiety. The current study adapted the Intolerance of Uncertainty Index-A for Children (IUI-A-C), and created a single-item Intolerance of Uncertainty Clinician-Rated Index (IUCR), both of which assess a youth's general inability to endure uncertainty. Psychometric properties of these two measures were evaluated. Participants were 146 youth aged 7-17 years seeking treatment for anxiety. The IUI-A-C evidenced individual item performance (i.e., correlations between each item and the total remainder score > .40, ps <.001), internal consistency, convergent validity with the IUCR and self-report measures of anxiety and functional impairment, divergent validity with ADHD severity, and retest reliability with a mean interval of over four weeks. The IUCR also evidenced convergent validity with the IUI-A-C and self-report measures of anxiety and functional impairment and divergent validity with ADHD severity. The IUI-A-C predicted composite principal diagnosis severity but did not predict composite GAD diagnosis severity. The IUI-A-C and IUCR have utility as measures of IU in youth. The role of IU in specific anxiety disorders and future research are discussed.