Feasibility of Conducting a Randomized Controlled Trial Comparing Standard FBT and Guided Self-Help FBT for Adolescent Anorexia Nervosa
Phase: NA
Conditions: Anorexia Nervosa
Sponsor: Stanford University

September 20, 2021 
Feasibility Study Comparing Standard FBT and Guided Self-Help FBT for Adolescent Anorexia Nervosa 
NCT04957498  
 
 

Study Protocol and Statistic Analysis Plan 
 
 
While Family Based Treatment (FBT) is an evidenced based therapy for adolescents with 
Anorexia Nervosa (AN; Lock and Le Grange 2013; Lock 2018), patients struggle to access the treatment. 
A preliminary case series implementing a parent’s only guided self-help version of FBT (GSH-FBT) 
aimed to address this gap in care (Lock J, Darcy A et al. 2017). This study expands on the previous data 
to determine the feasibility of GSH-FBT by piloting a randomized controlled trial of GSH-FBT as 
opposed to virtual FBT (FBT-V). Specifically, the pilot study aims to compare GSH-FBT to FBT-V 
through (1) recruitment and retention rates, (2) weight change and eating disorder symptoms, (3) parental 
self-efficacy of refeeding, and (4) efficiency (therapist time over participant outcomes). 
 
This study recruited 40 families with an adolescent between the age of 12 to 18 diagnosed with 
DSM-V criteria for AN. Recruited occurred at two sites: Stanford University and McMaster Unviersity. 
Families were randomized to either GSH-FBT or FBT-V. GSH-FBT used an online platform with 
lectures, readings, and home-work assignments. Over the course of 4-6 months, parents were instructed to 
complete online modules and attend twelve 20 to minute coaching sessions with a trained therapist 
“coach.” The coach would direct parents to specific content, answer questions about the material, and 
assign homework. FBT-V included fifteen 60 minutes sessions of FBT conducted by a trained therapist 
over a secure online video conferencing system. As is standard for FBT, the entire family would attend 
session in FBT-V. 
 
Data was collected on participants from participants at three major time points, baseline (BL), end 
of treatment (EOT), and 3-month follow-up. Weight data was also collected for each session (as is in-line 
with FBT). Expected Mean Body Weight (EBW) was used to assess weight restoration. Online surveys 
were administered after sessions 1 through 8 and all major time points. Surveys would consist of the 
measures—Parents versus Anorexia Nervosa Scale (Rhodes, Baillie, Brown, & Madden, 2005), Therapy 
Suitability and Patient Expectancy, Beck Anxiety Inventory (Beck and Steer 1993), Beck Depression 
Inventory-11 (Beck, Steer et al. 1996), and the Helping Alliance Questionnaire  (deWeert-Van Oene, de 
Jong et al. 1999). All major assessment timepoints would include the Eating Disorder Examination (EDE; 
Cooper and Fairburn 1987, Fairburn, Cooper et al. 2008) conducted by assessor unaware of treatment 
condition. 
 
Analysis was conducted on SPSS Version 27. A descriptive analysis was used to examine within 
and between group effects at the major time points and bi-weekly mediator assessments during the first 8 
weeks of treatment. As the study is not adequately powered, descriptive statistics and effect size are 
reported. Correlations were used to assess the bi-weekly mediator assessment. In line with intent to treat 
principles, percentages are based on a denominator of the total N per arm barring investigator 
withdrawals. Efficiency was calculated through average therapist time per participant over the EDE 
outcome and EBW.