Intolerance of uncertainty as a predictor of anxiety severity and trajectory during the COVID-19 pandemic

Background: Efforts to identify risk and resilience factors for anxiety severity and course during the COVID-19 pandemic have focused primarily on demographic rather than psychological variables. Intolerance of uncertainty (IU), a transdiagnostic risk factor for anxiety, may be a particularly relevant vulnerability factor. Method: N = 641 adults with pre-pandemic anxiety reported their anxiety, intolerance of uncertainty, and other pandemic and mental health-related variables at least once and up to four times during the COVID-19 pandemic, with assessments beginning in Summer 2020 through Winter 2021. Analyses were preregistered on the Open Science Framework. Results: Higher intolerance of uncertainty at the first pandemic timepoint predicted more severe anxiety, but also a sharper decline in anxiety across timepoints. This finding was robust to the addition of pre-pandemic anxiety and demographic predictors as covariates. Younger age, lower self/parent education, and experience of COVID-19 illness at the first pandemic timepoint predicted more severe anxiety across timepoints, but did not predict anxiety trajectory. Conclusions: Differential levels of IU at the outset of the pandemic prospectively predicted more severe anxiety and a sharper decrease in anxiety over time. This finding was robust to the inclusion of covariates, including pre-pandemic anxiety and various demographic characteristics.