Investigating the effect of intolerance of uncertainty on catastrophic worrying and mood.

Intolerance of uncertainty (IU) is a construct known to influence catastrophic worry and is often observed in Generalized Anxiety Disorder (GAD). Research into the psychological manifestations of GAD suggests IU is associated with worry, but has not confirmed a causal link. The current study investigated the relationship between catastrophic worry and IU in a non-clinical undergraduate and postgraduate population (n = 46), with a mean age of 26.8 (SD = 5.52 years), where 71.74% were women. Participants received either a high or low IU manipulation, mood was measured throughout the study on 100 point visual analogue scales (VAS), and worry was measured using the catastrophising interview (CI). The high IU group generated significantly more catastrophising steps than the low IU group. Increased levels of sadness and anxiety were observed in the high as compared to the low IU group post IU manipulation, and this difference was maintained throughout the CI interview. A mediation analysis revealed that sadness and anxiety did not significantly mediate the relationship between IU and number of CI steps. These findings have implications for GAD treatment, as they suggest that manipulating IU affects measures of worry and its associated emotional and behavioural symptoms.