An interventional study of Eating Disorder Dynamic Intervention in Eating Disorders, Anorexia Nervosa and Bulimia Nervosa, sponsored by Trustees of Dartmouth College. Recruiting at 1 site in United States. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-07-16.
Sponsored by Trustees of Dartmouth College · Not applicable, Interventional, and Treatment
The goal of this study is to develop and test a digital program to help people with eating disorders in their everyday lives. The program uses brief surveys and sensor data collected by smartphones to understand when someone may be at higher risk for behaviors like restricting food, binge eating, or using unhealthy weight control behaviors.
In this study, 170 adults with eating disorders will take part. They will regularly report on their thoughts, feelings, and behaviors throughout the day. Based on this information, the program will send "just-in-time" support, which involves short, tailored suggestions that encourage the use of helpful coping skills right when they are most needed.
The study has three main goals:
To better understand risk patterns:
The investigators will use real-time data to build personalized models that predict when someone is at higher risk for eating disorder behaviors based on their own data and patterns.
To test which therapy skills work best and why:
The investigators will examine how different evidence-based therapy skills (such as managing urges, improving mood, reducing strict dieting, and improving body image) help reduce eating disorder behaviors in daily life, and what psychological factors explain these effects.
The investigators will assess whether participants find the digital support helpful, easy to use, and acceptable in their daily routines.
Exclusion Criteria:
All participants will receive just-in-time adaptive interventions when their personalized model identifies that they are at risk for an eating disorder behavior. The content of the just-in-time adaptive intervention (i.e., the therapy skill targeted) will be randomized at the point of just-in-time adaptive intervention delivery.
Behavioral: Eating Disorder Dynamic Intervention
Participants will use a smartphone-based program designed to support eating disorder recovery in daily life. Participants will complete brief surveys about their mood, thoughts, and behaviors, and the smartphone will also passively collect activity-related data. This information is used to detect times when a person may be at higher risk for eating disorder behaviors. Participants will watch 4 video modules that introduce the core enhanced cognitive-behavioral therapy skills for eating disorders (reducing dietary restraint, urge management, emotion regulation, and improving body image), provide rationale, and prompt participants to complete interactive activities to practice these skills. Participants will then receive micro-randomized JITAIs prompting them to use these skills in their daily lives; micro-randomization will be used to deliver a JITAI from one of the 4 skill categories (reducing dietary restraint, urge management, emotion regulation, improving body image) or no JITAI.
Area under the receiver operating curve (AUC)
Performance of the eating disorder behavior prediction models will be evaluated by computing the area under the receiver operating curve (AUC) for each participants' models on two-weeks of held out (test) data (collected during weeks 5 and 6 of the data collection procedure). The AUC can take on values between 0 and 1, with higher values indicating superior model performance.
Time frame: Weeks 5 and 6 of data collection
Brier Score
Performance of the eating disorder behavior prediction models will be evaluated by computing the Brier score for each participants' models on two-weeks of held out (test) data (collected during weeks 5 and 6 of the data collection procedure). The Brier score can range from 0 to 1 with lower values indicating less model error (i.e., better model performance).
Time frame: Weeks 5 and 6 of data collection
Binge eating
Binge eating occurrence during the data collection protocol will be measured. Binge eating at each ecological momentary assessment survey will be assessed by the question, "Thinking about your most recent eating episode, did you experience loss of control?" (Answer choices = Yes or No).
Time frame: Weeks 7 through 16 of data collection
Dietary restriction
Dietary restriction will be measured during the data collection protocol. Dietary restriction will be assessed at each ecological momentary assessment survey by the questions, "Thinking about your most recent eating episode, did you limit the amount of food you ate to influence your shape?", "Thinking about your most recent eating episode, did you exclude specific foods to influence your shape or weight?", and Since the last survey, have you skipped a meal or snack?" (Answer Choices = Yes or No).
Time frame: Weeks 7 through 16 of data collection
Compensatory behaviors
Dietary restriction will be measured during the data collection protocol. Dietary restriction will be assessed at each ecological momentary assessment survey by the questions, "Since the last survey, have you engaged in any of the following? Self-induced vomiting," "Laxative use (to influence shape or weight)," "Diuretic use (to influence shape or weight)," "Diet pill use (to influence shape or weight)," "Exercise (to influence shape or weight)," and "Other behavior to influence shape or weight" (Answer Choices = Yes or No).
Time frame: Weeks 7 through 16 of data collection
Feasibility and Acceptability Questionnaire
Acceptability will be evaluated via the Feasibility and Acceptability Questionnaire. These data will be collected after participants have completed the 16 weeks of data collection using the EDDI app. Mean ratings ≥ 5 (on the seven-point Likert rating scales) on acceptability items will be considered to indicate acceptability. The response scale is as follows: 1=Strongly Disagree 2=Disagree 3=Disagree a little 4=Neither agree nor disagree 5=Agree a little 6=Agree 7=Strongly Agree, with higher scores indicating greater acceptability.
Time frame: End of study assessment (after week 16 of data collection)
System Usability Scale
Acceptability will be evaluated via the System Usability Scale. These data will be collected after participants have completed the 16 weeks of data collection using the EDDI app. Mean ratings ≥ 4 (on the five-point Likert rating scale) on System Usability Scale items will be considered to indicate acceptability. The response scale runs from 1 = Strongly Disagree (minimum value) to 5 = Strongly Agree (maximum value), with higher ratings indicating greater usability. Items 2, 4, 6, 8, and 10 will be reverse coded to align with higher ratings indicating greater usability.
Time frame: End of study assessment (after week 16 of data collection)
Percentage of Eligible Participants Enrolled
Feasibility of the EDDI app will be evaluated by computing the percentage of eligible participants enrolled. This will be computed by dividing the number of enrolled participants by the total number of eligible participants and multiplying by 100. At least 85% of eligible participants enrolled will be considered to demonstrate feasibility.
Time frame: Through study completion, an average of 4 months
Attrition Rate
Feasibility of the EDDI app will be evaluated by computing the attrition (drop out) rate. This will be computed by dividing the number of participants who discontinue the study prior to the end of study assessment by the total number of enrolled participants and multiplying by 100. An attrition rate of less than 15% will be considered to demonstrate feasibility.
Time frame: Through study completion, an average of 4 months
Percentage of JITAIs Producing Skill Use
Feasibility of the EDDI app will be evaluated by computing the percentage of JITAIs that produce participant-reported skill use. This will be computed by dividing the instances of reported skills used by the total number of delivered JITAIs and multiplying by 100. JITAIs producing skill use at least 80% of the time will be considered to demonstrate feasibility.
Time frame: Through study completion, an average of 4 months
Body image concerns (Eating Disorder Examination Questionnaire-Short Form)
Body image concerns will be measured as a possible mediator of the effect of JITAIs on eating disorder behaviors. Body image concerns will be quantified as the mean rating across the body image items on the Eating Disorder Examination Questionnaire-Short Form, adapted to be rated on a five-point Likert scale as follows: 0=Very slightly/not at all 1 = A little 2 =Moderately 3 = Quite a bit 4= Extremely. Higher mean ratings indicate great body image concerns. Minimum mean score on the items is 0 and maximum is 4.
Time frame: Weeks 7 through 16 of data collection
Cognitive dietary restraint (Eating Disorder Examination-Questionnaire)
Cognitive dietary restraint will be measured as a possible mediator of the effects of JITAIs on eating disorder behaviors. Cognitive dietary restraint is assessed by the mean score across four selected dietary restraint items from the Eating Disorder Examination Questionnaire, modified to be assessed on the following response scale: 0=Very slightly/not at all 1 = A little 2 =Moderately 3 = Quite a bit 4= Extremely. The minimum mean score is 0 and the maximum mean score is 4, with higher scores indicating greater dietary restraint.
Time frame: Weeks 7 through 16 of data collection
Negative affect (Positive and Negative Affect Schedule)
Negative affect will be measured as a possible mediator of the effects of JITAIs on eating disorder behaviors. Negative affect is assessed by the mean score across six selected negative affect items (upset, hostile, ashamed, afraid, nervous, guilty from the Positive and Negative Affect Schedule, modified to be assessed on the following response scale: 0=Very slightly/not at all 1 = A little 2 =Moderately 3 = Quite a bit 4= Extremely. The minimum mean score is 0 and the maximum mean score is 4, with higher scores indicating greater negative affect.
Time frame: Weeks 7 through 16 of data collection
Plan to share: Yes — To facilitate open science, all de-identified data from the present study will be shared via National Data Archive (NDA), unless doing so would violate research ethics or privacy of participants (e.g., raw smartphone location sensor data will not be shared as this would violate participants' privacy and confidentiality). In addition to the subject level data described above, subject level data on adherence to the ecological momentary assessment protocol and responsivity to just-in-time adaptive interventions will also be shared via NDA.
Supporting information: Study protocol, Sap, Icf
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