INTERconNEcT-Eds: a Guided Self-help Mobile App to Improve Outcome in Eating Disorders

Change from baseline in Clinical Outcomes in Routine Evaluation Outcome Measure (CORE-OM):

The CORE-OM is a 34-item validate, self-report scale (of which 25% are reverse items) assessing global distress of the subject across 4 domains: \[Well-being (4 items); Functioning (12 items); Problems/symptoms (12 items); Risk (to self and to others) (6 items)\] over the last week. Items are answered on the same five-point scale (0-4) ranging from 'not at all' to 'most or all the time'. Overall, the measure is problem scored (i.e. higher scores indicate more problems). Scores are reported as means across items that give a 'pro-rated' score if there are incomplete responses.

Change from baseline in the Eating Disorder Examination Questionnaire

Questionnaire (EDE-Q 6.0): it is a self-report scale assessing eating disorder psychopathology and behaviors. The questionnaire is made up of 22 items, rated on a 7-point from 0 to 6. Higher scores reflecting greater severity or frequency. It also provides frequency data on key behavioral features of eating disorders, in terms of the number of episodes of the behavior over the preceding 28 days, and the number of days on which the behavior has occurred. Items are grouped into 4 subscales: restraint, weight concern, shape concern and eating concern.

Change from baseline in the Inventory of Interpersonal Problems

The IIP-32 is a self-report scale 32-item inventory of distressing interpersonal behaviours the respondent identifies as "hard to do" (i.e., behavioural inhibitions) or "does too much" (i.e., behavioural excesses) on a 0 (not at all) to 4 (extremely) Likert scale. It provides an overall score and 8 subscale scores: (Domineering/Controlling, Vindictive/Self-centered, Cold/distant, Socially inhibited, Nonassertive, Overly accommodating, Self-sacrificing, Intrusive needy). Higher scores in each scale indicate the presence of interpersonal difficulties.

Change from baseline in the Autonomous and Controlled Motivation for Treatment Questionnaire

The ACMTQ consists of two subscales assessing autonomous and controlled motivation for treatment through 12-items on a seven-point Likert scale ranging from 1 (strongly disagree) to 7 (strongly agree). Higher scores indicate a stronger endorsement of the motivation type.

Change from baseline in the Difficulties in Emotion Regulation Scale

The Difficulties in Emotion Regulation Scale (DERS) is a 5-point self-report instrument measuring emotion regulation problems. The 36 items (of which 11 are reverse items) asks respondents how they relate to their emotions in order to produce scores on the following subscales: non acceptance of emotional responses, difficulty engaging in goal-directed behaviour, impulse control difficulties, lack of emotional awareness, limited access to emotion regulation strategies, lack of emotional clarity. Higher scores suggest greater problems with emotion regulation.

Change from baseline in the EQ-5D-5L

The EQ-5D-5L descriptive system includes five dimensions: mobility (MO), self-care (SC), usual activities (UA), pain/discomfort (PD), and anxiety/depression (AD). Each dimension is articulated into five severity levels: no problems, slight problems, moderate problems, severe problems, extreme problems. The EQ-5D questionnaire also includes a visual analogue scale (EQ VAS) on which participants indicated their self-rated health at the time between 0 (worst imaginable health) and 100 (best imaginable health).

Change from baseline in Body Mass Index

Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. BMI categories: Underweight = \<18.5 Normal weight = 18.5-24.9 Overweight = 25-29.9 Obesity = BMI of 30 or greater

Change from baseline in use of care services

Participant's Service Use (PSU). Participants in study 2 will indicate the type of care service used in the last 6 weeks and the number of days they have used a service in the last 6 weeks.