Author: Ella Keegan
Keegan, Ella, 2023 Shortening and managing the impact of lengthy treatment waitlists for people with non-underweight eating disorders, Flinders University, College of Education, Psychology and Social Work
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People with eating disorders are often placed on long waitlists for treatment. This is problematic as increased time on waitlists has been shown to predict dropout from eating-disorder-focused cognitive behavioural therapy (CBT-ED). The COVID-19 pandemic has exacerbated this issue with numerous studies showing increased waiting times for treatment. Thus, the overarching aim of this thesis was to determine strategies to respond to lengthy waitlists in a pandemic world. This involved two specific aims. The first aim was to identify strategies to shorten waitlists for treatment. Given waitlists are unfortunately a fact of life, the second aim was to identify strategies to manage the impact of lengthy waitlists on dropout. Three potential strategies were examined among participants aged 15 and above: (1) waitlist interventions; (2) shorter treatment; and (3) precision medicine.
Shorter treatment was evaluated using a meta-analysis (Chapter 3) and the main PhD study (Chapter 8). Results demonstrated that 10-session cognitive behavioural therapy (CBT-T) reduced eating disorder symptoms, clinical impairment, and negative affect. Additionally, results were largely maintained over follow-up. Non-completion, abstinence, and remission rates were comparable to those observed for longer CBT-ED.
To inform a precision medicine approach, we examined potential baseline moderators and predictors of outcome and retention in two studies (Chapters 5 and 8). For anorexia nervosa, having low central coherence produced better outcomes in treatment. In contrast, high central coherence produced better outcomes for non-underweight eating disorders. Additionally, people with non-underweight eating disorders with low set shifting did better in treatment. Finally, those who were overweight were more likely to complete treatment, and people with atypical anorexia nervosa were less likely to complete or respond favourably to CBT-T.
While there are many potential targets for waitlist interventions, our resources enabled us to evaluate two. A meta-analysis (Chapter 4) revealed that central coherence and set shifting inefficiencies are as relevant to non-underweight eating disorders as they are to anorexia nervosa. This suggested that people with non-underweight eating disorders might benefit from cognitive remediation therapy (CRT), a treatment for anorexia nervosa that targets central coherence and set shifting and improves retention. Thus, we developed and refined a CRT intervention for non-underweight eating disorders (CRT-Brief) based on stakeholder feedback obtained in a qualitative feasibility study (Chapter 6). We then conducted a randomised controlled trial (Chapter 8) comparing two waitlist interventions (CRT-Brief and brief contact) to control among participants waitlisted for CBT-T. Both waitlist interventions doubled retention in CBT-T.
Results support the use of shorter treatment as a strategy to shorten waitlists by enabling more people to be seen more quickly, providing justification for a randomised controlled trial comparing CBT-T to longer CBT-ED. Results also suggest that waitlist interventions are a viable strategy to obviate the impact of lengthy waitlists by improving retention in subsequent treatment. Further work is required before a precision medicine approach can be adopted as a strategy to shorten waitlists for eating disorders, and there is an urgent need for research aimed at identifying useful treatments for atypical anorexia nervosa.
Keywords: CBT-T, non-underweight eating disorders, waitlist, CRT, brief contact
Subject: Psychology thesis
Thesis type: Doctor of Philosophy
Completed: 2023
School: College of Education, Psychology and Social Work
Supervisor: Tracey Wade