Measuring Intolerance of Uncertainty after Acquired Brain Injury: Factor Structure, Reliability, and Validity of the Intolerance of Uncertainty Scale-12 (preprint)

Intolerance of uncertainty (IU) is a risk factor for poor mental health. Acquired brain injury (ABI; e.g., stroke, traumatic brain injury), often brings considerable uncertainty and increased mood disorder vulnerability. The Intolerance of Uncertainty Scale-12 (IUS-12) is a brief, well-validated measure of IU argued to comprise two subscales, Prospective Anxiety and Inhibitory Anxiety. Here, for the first time, we investigated its reliability and validity (N = 118), and factor structure (N = 176), in ABI. Both subscales had high test-retest reliability (ICCs of 0.75 and 0.86) and were significantly associated with mood disorder symptoms. The two-factor model was superior to a one-factor IU model fit. IUS-12 scores were stable despite great uncertainties of COVID-19, consistent with its conceptualisation as a trait. Consistent with recent debates about the factor structure of IUS-12 and, in exploratory analyses, we found indications of improved fits that warrant further investigation in independent ABI samples.

Measuring Intolerance of Uncertainty after Acquired Brain Injury. Part 1: The Factor Structure of the Intolerance of Uncertainty Scale-12 (preprint)

Intolerance of uncertainty (IU) is a risk factor for poor mental health. Acquired brain injury (ABI), such as stroke or traumatic brain injury, often brings considerable uncertainty. This is the first of a two-part investigation of the psychometric properties of the Intolerance of Uncertainty Scale-12 (IUS-12) in ABI. Here, we evaluate its internal consistency and factor structure in 176 adults with ABI. A two-factor structure (Prospective Anxiety and Inhibitory Anxiety) was superior to a one-factor model. However, some fit statistics were unacceptable. In an exploratory factor analysis, a new two-factor model emerged with a superior fit. A bifactor model provided even better fit, though the sample size precluded exhaustive evaluation. For now, retaining the original Prospective Anxiety and Inhibitory Anxiety subscales is recommended for ABI. IUS-12 scores did not differ pre- or during COVID-19 assessment, suggesting the IUS-12 is measuring individual differences regardless of uncertainty levels.