Investigating the relationship between intolerance of uncertainty and threat extinction learning whilst controlling for anxiety-related symptoms

Exposure-based therapies operate on principles of threat conditioning and extinction. Previous research has demonstrated that trait-level intolerance of uncertainty (IU) is specifically associated with worsened extinction learning whilst controlling for trait anxiety. Hence, IU may serve as a useful focus for researchers aiming to improve the effectiveness of exposure-based therapies as research suggests that IU can be modified clinically. Yet, little is known as to whether IU is associated with extinction learning whilst controlling for anxiety-related symptoms. A two-day Pavlovian conditioning task was carried out, consisting of threat acquisition, extinction, and extinction retention phases. Participants (N = 101) completed IU, trait anxiety, and various disorder-specific questionnaires e.g., panic disorder. before engaging in the conditioning procedure. Skin conductance magnitudes, and behavioural ratings of anxiety and stimulus expectancy were used as indices of conditioned responding, and extinction by extension. Analyses revealed that successful threat conditioning was observed for all three measures during threat acquisition, yet extinction was not observed during the extinction and retention phases. IU was not specifically associated with individual differences in extinction as indexed by differential SCR magnitudes, contradicting prior research. Further, IU was specifically associated with differential stimulus expectancy and anxiety ratings within extinction and retention respectively, whilst controlling for symptom measures. Lastly, IU was not associated with any other extinction measure. Overall, IU failed to predict extinction learning consistently throughout the experiment, although this may be due to experimental artefacts. The authors outline considerations for future research on the relationship between IU and extinction learning.