Abstract/Summary

Anxiety disorders are one of the most common mental health problems among children and adolescents. Studies in adults suggest that intolerance of uncertainty (IU) is closely linked to a range of anxiety disorders; however, there is a relative lack of research focusing on IU in children and young people. Four studies are presented in this thesis that together aim to: 1. review existing evidence for associations between IU, anxiety, and worry in children and adolescents; 2. begin addressing issues around the assessment of IU in preadolescent children. Study 1, a meta-analysis of the current literature on IU, anxiety, and worry in children and adolescents revealed robust relationships between IU and both anxiety and worry. Following this, study 2 assessed the psychometric properties of the current child IU questionnaire measure in a preadolescent sample. Although the measure showed good psychometric properties, younger children had some difficulty understanding certain items. Studies 3 and 4 adapted behavioural tasks designed to assess IU and evaluated the suitability of these tasks for preadolescent children. Further, these studies examined children’s reactions to uncertainty and explored whether these tasks can capture reactions to uncertainty that are related with self-reported IU, anxiety and worry. Both studies concluded that the tasks were suitable for preadolescent children. In addition, general reactions to uncertainty manipulations such as increased worry, more information seeking and longer reaction times were found, although there was some task specificity. There was some evidence that responses on these tasks may be associated with IU, but this was strongest for subjective reports of task-related certainty rather than objective measures of task performance. Overall, these studies provide a systematic overview of the current IU literature in children and young people, reveal shortcomings of the self-reported IU for younger children and provide new assessments to measure IU in preadolescent children. The work presented in this thesis underlines the importance of taking age and cognitive development into account when designing and selecting IU assessments in children and leads to several suggestions for future research in order to improve understanding of the IU specific mechanisms across development.