Residential treatment for eating disorders and the influence of trauma on treatment outcomes

Abstract

The overarching aims of this doctoral project were firstly to investigate the effectiveness of the first Australian eating disorder residential service, including comparison with a day program and investigation of a broad range of outcomes at end-of-treatment and follow-up. Secondly, this project aimed to establish prevalence rates for CPTSD in eating disorders and examine its impact on residential treatment outcomes. To accomplish these aims, six studies were conducted as described in Chapters 4-9 of this Thesis. Study 1 (Chapter 4) aimed to compare the pre- to post-treatment effectiveness of residential care with an eating disorder day program, and Study 2 (Chapter 5) aimed to investigate the outcomes and predictors of functional change from this residential service at a 6-month follow-up. The aim of Study 3 (Chapter 6) was to systematically review the literature on how trauma and PTSD affect eating disorder treatment outcomes. Study 4 (Chapter 7) aimed to establish prevalence rates and clinical correlates of CPTSD in eating disorders. Study 5 (Chapter 8) aimed to determine whether symptoms of CPTSD moderate outcomes from eating disorder residential care, and the aim of Study 6 (Chapter 9) was to explore whether CPTSD symptoms themselves improved over the course of residential treatment. The findings across all studies presented in this Thesis enhance current knowledge of the effectiveness of residential treatment for eating disorders and provide the first global evidence on the prevalence and impact of CPTSD in eating disorders. Some of the limitations of previous residential treatment literature have been addressed, including highlighting that residential treatment improves not only weight, but also cognitive and affective eating disorder symptoms, comorbid mood and anxiety, and an array of quality of life and functional outcomes. The trajectory of residential outcomes has been clarified, highlighting the importance of immediate and sufficiently intensive stepdown care. This Thesis has shown that CPTSD is likely to be the most common comorbid trauma-related presentation in eating disorders, and is a marker of greater eating psychopathology. However, comorbid CPTSD or PTSD may not necessarily predict poorer response to residential treatment. Further research is needed to determine whether these findings are unique to residential care given its holistic focus, home- like environment, and likely greater sense of safety for trauma-affected individuals compared to hospital treatment settings.

Date of Thesis submission	2025
Original language	English
Awarding Institution	Western Sydney University
Sponsors	Australian Government Research Training Program Scholarship
Supervisor	Deborah Mitchison (Supervisor), Phillipa Hay (Supervisor) & Kathy Tannous (Supervisor)