Section one presents a systematic literature review exploring the effectiveness of interpersonal and relational based interventions in eating disorder treatment. Four databases were systematically searched, and 22 papers were synthesised using an abridged Synthesis Without Meta-analysis. Findings highlighted two effective interventions: Interpersonal Psychotherapy and Compassion Focused Therapy. These interventions produced comparable treatment outcomes to Cognitive Behavioural Therapy and offered a more stable recovery. Similar mechanisms underpin these interventions as they directly address underlying maintaining factors within the self. Clinical implications and directions for future research are discussed.

Section two details a qualitative exploration of voice personification and multiplicity alongside the Eating Disorder Voice in young women experiencing an Eating Disorder. A three-layered adapted Experience-Based Co-Design approach was implemented. Initial analysis of data gathered in layer one and two was presented within layer three to obtain participant’s feedback on the interpretation of their stories. Eleven stories of lived experience were then analysed using Narrative Analysis. Three chapters emerged: (1) A Continuum of the Eating Disorder Voice experiences, (2) Conflict between the Self and the Eating Disorder Voice, and (3) The role of an Eating Disorder Voice in the maintenance of an Eating Disorder. Findings indicate a continuum of the Eating Disorder Voice, including experiences of voice personification and multiplicity. Furthermore, the results demonstrate how the relationship with an Eating Disorder Voice maintains an eating disorder. Clinical implications are discussed, including adapting eating disorder treatment to reflect the continuum of Eating Disorder Voice experiences.

Section three contains a critical appraisal, which discusses the methodological and ethical decisions and issues that arose while conducting the empirical paper. The paper also offers personal reflections and insights into the process of collaborative research and the importance of listening to an unheard population. For a glossary of key terms within this thesis see Appendix 3-A.