Family-Based Treatment at Home in Adolescents With Eating Disorders and Co-occurring Mental Health Conditions

Weight - each session The weight of the adolescent in kilograms (kg) is measured weekly to monitor progress. The weight is measured by an FBT-H practitioner in an FBT-H session. The weight is measured in the same way every week (e.g., in underwear). This is a standard measurement associated with the FBT intervention and takes approximately 5 minutes.

The ORS is a questionnaire in which participants indicate how they are doing in four components of their lives: personal, interpersonal, social, and general (Miller et al., 2003); translated by Hafkenscheid et al., 2003). These four components form the four items in this questionnaire, which can be answered on a scale from 0-10. There is a child and adult version of the ORS. A score of more to the left (0) indicates a negative score on the corresponding component, and a score of more to the right (10) indicates a more positive one. The internal consistency, measured by Cronbach's alpha, is .97 (26). Adolescents and their parents participating in this study will be asked to fill out this questionnaire at the beginning of each session, which requires approximately 1 minute.

The SRS is a questionnaire in which adolescents express how they have experienced a session. The four items covered are relationship/contact, goals and topics, approach and method, and overall satisfaction. The SRS has the same setup as the previously mentioned ORS. The internal consistency, measured by Cronbach's alpha, is .88. Adolescents and parents participating in this study will be asked to fill out this questionnaire at the end of each treatment session, which takes approximately 1 minute.

The EDE-Q is a self-report questionnaire used to assess the behaviours and characteristics of ED. The EDE-Q consists of a global scale (22 items) and four subscales: restraint, eating concern, weight concern, and shape concern. Each question can be answered on a scale from 1 to 6 or with a yes/no response. Satisfactory levels of internal consistency were observed.

Kidscreen-27 is a questionnaire measuring the quality of life of children in five dimensions: physical well-being, mental well-being, parent relations and autonomy, social support (from peers), and school situation. It consists of 27 questions, each of which has five answer options. Cronbach's alpha for all scales varies between average and good.

The OKIV-R consists of questionnaires that measure how parents view the relationship with their child and how children view the relationship with their parents. The child-mother, child-father, and parent-child versions are available. It has 21 statements, and each statement has five answer options varying from never (1) to always (5). The revised version of the OKIV (OKIV-R) has high internal consistency.

The OBVL is a questionnaire for parents about experiencing stress in parenting (Veerman et al., 2014).The OBVL consists of five scales (34 questions): parent-child relationship, parenting competence (7), depressive moods (7), role limitations (6), and health complaints (8). Each question has four answers that the parent can choose, varying from do not agree to totally agree. The scales of the OBVL have a reliability between .90 and .96 (McDonald's Omega).