title: Predictors of generalised anxiety disorder: the role of intolerance of uncertainty, negative metacognitive beliefs, and experiential avoidance
Creators: name: Whittaker Bork, Natalie
Publisher: name: University of Liverpool Repository
Year: 2014

description: The overarching aim of this thesis was to gain an increased understanding of the psychological processes related to generalised anxiety disorder (GAD) and how they contribute to the development and maintenance of the disorder. Changes in the diagnostic criteria of GAD over the years, have led to increased identification of specific psychological processes that may be responsible for the disorder, all of which offer a plausible explanation. However, limited empirical research exists exploring the relative merits, or have made direct comparisons of each. Therefore, this thesis attempts to answer the following questions: Which psychological factors contribute to the severity of worry? and do the identified psychological factors explain the development of GAD? Delineation of these psychological processes may hold the key to increased efficacy of treatments, as outcomes are currently poor, which lead to increased health care utilisation and high economic costs to the public health service. Improving treatments is clearly an important factor for GAD sufferers who often experience significant impairment in overall functioning and quality of life. Chapter 2 presents an overview of the relevant literature, which provides a point of orientation for the research section that follows. This will initially offer a historical context, followed by an overview of GAD, the role of negative life events, and finally considers the implications for psychopharmacological and psychological treatments. The evolution of the development of psychological models of anxiety is outlined, which provided the foundation for the development of some of the current leading psychological models of GAD within this field. These have led to the identification of key processes that offer a clear hypothesis and explanation of the phenomena seen in worry and GAD; the most recent models included within this review are the Intolerance of Uncertainty (IU) model (Dugas, Gagnon, Ladouceur, &amp; Freeston, 1998), the Metacognitive model (Wells, 1995, 1999), and finally the Acceptance Based model (Roemer, Salters, Raffa, &amp; Orsillo, 2005). This leads into the final section of Chapter 2, which is a systematic review of the key processes to be explored within this thesis, the processes of interest are IU, negative metacognitive beliefs about worry, and finally experiential avoidance. Chapter 3 leads into the empirical paper, which provides a detailed account of the research and the outcomes. This research attempted to address some of the gaps in the literature by being the first to explore all three of these constructs in one study. The aim of which was to understand more about what factors are related to the prediction of worry severity and GAD status in a non-clinical sample. Additionally, this study attempted to address some of the limitations of previous literature by using a prospective design, which allowed inferences on causality to be made. Students were recruited and completed the study via a web-based design, completing measures at two time points. The findings of this research are presented with an overall discussion of how this relates to previous research. These are discussed in the context of several limitations. In the final chapter, the implications of the research are outlined, with reference to the theoretical and clinical relevance. In addition, methodological considerations are highlighted, including the relative strengths and limitations of the research. As the dissemination of research findings is an important process for any research, the next section is an article prepared for those participants who took. The final section relates to how future studies can continue to bridge the gaps within the literature, this is outlined in the form of a research proposal. Further empirical research is required within this field, specifically; replication of the current study within clinical samples would further and extend the findings presented in Chapter 3. The thesis then closes with an overall conclusion.