Psychological mechanisms underpinning change in intolerance of uncertainty across anxiety-related disorders: New insights for translational research

Intolerance of uncertainty (IU), the tendency to find uncertainty negative, is a fundamental transdiagnostic dimension across anxiety-related disorders. Over the past two decades, there has been an increase in both clinical and experimental research on the role of IU in the maintenance and treatment of anxiety-related disorders. However, there has been a lack of integration of research findings from a mechanistic perspective, which has slowed progress in translational research. This review seeks to fill this gap by synthesising the clinical (e.g. randomised controlled trials) and experimental (e.g. lab-based) literature on the psychological mechanisms that drive change in IU across anxiety-related disorders. The review highlighted that: (1) cognitive restructuring, supported by mechanisms such as cognitive appraisal, modify IU-related cognitions, (2) behavioural exposures, supported by mechanisms such as inhibitory learning, alter IU-related cognitions and physiological arousal, and (3) mindfulness techniques underpinned by mechanisms such as attentional monitoring, decentering, and acceptance, change IU-related cognitions. Across the different therapeutic techniques reviewed, there was a lack of evidence for how different mechanisms change IU-related emotions and behaviours. Directions for further research include directly comparing the effectiveness of different mechanisms that produce change in IU across anxiety disorders and other mental health disorders, and examining the specificity of change in IU over other anxious traits. Overall, the findings provide a foundation for future translational research efforts to build upon maximising existing treatment interventions and/or to develop novel treatment interventions to target dispositional IU and situational uncertainty-related distress in anxiety-related disorders and beyond.