Establishing Guidelines into Labelling and Defining the Severe and Enduring Stage of Anorexia Nervosa: An Investigation into Cognitive Characteristics, Lived Experiences and the Professional Appraisal of the Disease

Abstract

Efforts dedicated towards staging Anorexia Nervosa (AN) has prompted a surge in research on patients that transition into the later stage. Two of the barriers in effectively progressing the field is the inconsistency in (1) labelling and (2) defining these presentations of AN. The primary focus of this thesis was to address this variability and contribute guidelines towards establishing a unified classification system. Following a literature review (Chapter 1), five aims were devised to address this topic with the first to determine how individuals in the later stage had previously been labelled and defined (Chapter 2). A limited understanding of cognitive functioning prompted the second aim of determining whether neuropsychological variability existed in the profile of these individuals. A systematic review (Chapter 3) revealed preliminary evidence of neuropsychological variability within the later stage of AN. The third aim further explored characteristics by investigating the trajectory of AN from its early development through to the later stage with evidence of changeability to the disorder as it transitioned over time (Chapter 4). The remaining studies were focused on investigating valuable perspectives, with the fourth aim dedicated to exploring preferences from individuals with lived experiences. A qualitative study (Chapter 5) revealed the majority of participants preferred the label ‘severe and enduring’ and a definition to include the feature of illness duration. The fifth aim was to explore and synthesise clinical knowledge of professional experts to reach consensus on this topic. Utilising the Delphi methodology (Chapter 6), two new labels were endorsed along with overlapping defining features from lived experience perspectives. Findings support recommendations made for a unified classification system (Chapter 7). This thesis outlines the multiple elements requiring consideration when establishing a label and definition for this subpopulation.