The Intolerance of Uncertainty Index: Replication and extension with an English sample.

Abstract

Intolerance of uncertainty (IU) is related to anxiety, depression, worry, and anxiety sensitivity. Precedent IU measures were criticized for psychometric instability and redundancy; alternative measures include the novel 45-item measure (Intolerance of Uncertainty Index; IUI). The IUI was developed in French with 2 parts, assessing general unacceptability of uncertainty (15 items, Part A) and manifestations of uncertainty approximating more common anxiety disorder symptoms (30 items, Part B). The psychometric stability of the back-translated English items of the IUI as well as the incremental variance of Parts A and B remain to be assessed. The current study involved 2 samples of English-speaking community participants (n = 437 and n = 309; 73% women and 27% men) who completed the IUI and several related measures. Exploratory and confirmatory factor analyses suggested a refinement of IUI items as well as a unitary structure for Part A and a 3-factor structure for Part B. Regression results suggested Parts A and B each provide incremental validity in measures of worry, generalized anxiety disorder symptoms, negative problem orientation, and depression. Comprehensive results, implications, and future research directions are discussed.