Maladaptive behaviours associated with generalised anxiety disorder.

Abstract

Generalised Anxiety Disorder (GAD) is a common anxiety disorder that follows a chronic course without treatment. This thesis examines how GAD may affect what people do, that is, the behavioural features of the disorder. Understanding these features has ramifications for our current diagnostic and theoretical conceptualisations of GAD, as well as our clinical management. The studies in this thesis aim to (1) identify, (2) measure, and (3) explore the correlates of maladaptive behaviours associated with GAD. The opening chapter reviews the extant literature and provides the rationale for the program of empirical studies that follows. Chapters two through six are presented as a series of papers. Chapter two describes the development of the Worry Behaviours Inventory (WBI), a self-report questionnaire that indexes maladaptive behaviours associated with GAD. In chapters three and four, the psychometric properties of the WBI are evaluated within classical test theory and item response theory. Considerable support for the reliability and validity of the WBI is provided. Chapter five examines how maladaptive behaviours associated with GAD change over the course of cognitive behaviour therapy for GAD and how reductions in these behaviours are predictive of treatment outcomes. Chapter six explores the associations between maladaptive behaviours and a number of cognitive factors that have been theorised to maintain GAD, including cognitive avoidance, intolerance of uncertainty and metacognitive beliefs. Engagement in maladaptive behaviours was shown to mediate the relationships between cognitive factors and GAD symptom severity. The final chapter of this thesis summaries key findings and their implications, in addition to detailing the limitations of this body of work and providing suggestions for future research. Current findings are consistent with contemporary cognitive models of and cognitive therapies for GAD and are supportive of further investigation into the inclusion of maladaptive behaviours in the classification of GAD.