What this trial measures

• Patient weightChange from study treatment week one to final session, an average of 25 weeks after week one (measured at weekly study treatment sessions), and to the one, three, and six-month follow-up session, up to 11 months after week one.

  Weight collected at each session.

• Generalized Anxiety Disorder (GAD-7)Change from week one of study treatment to post-treatment following final session, an average of 25 weeks after week one (measured at weeks one, six, and twenty), and to one, three, and six-month follow-up sessions, up to 11 months after week one.

  A 7-item scale that measures symptoms of Generalized Anxiety Disorder (GAD), such as feeling anxious or nervous, having trouble relaxing, irritability, and feelings of dread. Scores range from 0 to 21, with higher scores reflecting higher general anxiety.

• Patient Health Questionnaire - 9 (PHQ-9)Change from week one of study treatment to post-treatment following final session, an average of 25 weeks after week one (measured at weeks one, six, and twenty), and to one, three, and six-month follow-up sessions, up to 11 months after week one.

  A 9-item scale that measures symptoms of depression. Scores range from 0 to 27, with higher scores reflecting higher depression.

• Eating Disorder Examination Interview (EDE)Change from baseline assessed at screen visit to post-treatment following final session, an average of 25 weeks after baseline assessment.

  A semi-structured interview designed to assess current eating disorder psychopathology.

• Eating Disorder Examination Questionnaire (EDE-Q6)Change from week one of study treatment to post-treatment following final session, an average of 25 weeks after week one (measured at weeks one, six, and twenty), and to one, three, and six-month follow-up sessions, up to 11 months after week one.

  A 33-item self-report questionnaire that assesses the presence of eating disorders symptoms in the past 28 days. Eating Disorder examination questionnaire (EDE-Q 6.0) Scores range from 0 to 6, with higher scores reflecting higher eating disorder behaviors and attitudes.

• Eating Disorder - 15 Scale (ED-15)Change from study treatment week one to post-treatment following final session, an average of 25 weeks after week one (measured at weekly study treatment session), and to the one, three, and six-month follow-up session, up to 11 months after week one.

  A 15-item self-report measure that assesses eating disorder symptoms and behaviors, designed to measure session-by-session change for clinical and research purposes. Scores range from 0 to 6, with higher scores reflecting higher disordered eating attitudes and behaviors.

• Working Alliance Inventory Short (WAI-SR)Change from week one of study treatment to post-treatment following final session, an average of 25 weeks after week one (measured at weeks one, six, and twenty), and to the six-month follow-up session, up to 11 months after week one.

  A 12-item self-report measure that assess therapeutic alliance between the patient and therapist. (i.e., how comfortable the patient feels with the therapist, how much they trust the therapist, how much they feel the therapist is working towards their desired treatment goals, etc.). Scores range from 5 to 20, with higher scores reflecting higher therapeutic alliance.

• General Self-Efficacy Measure-Short FormChange from week one of study treatment to post-treatment following final session, an average of 25 weeks after week one (measured at weeks one, six, and twenty), and to the six-month follow-up session, up to 11 months after week one.

  A 6-item, short form assessment of the patient's perception of their own general self-efficacy. Scores range from 10 to 40, with higher scores reflecting higher self-efficacy.

• Approach/Avoidance of Weighing Questionnaire (AAWQ)Change from baseline assessed at screen visit to post-treatment following final session, an average of 25 weeks after baseline assessment.

  A 9-item, self-report questionnaire that assesses approach and avoidance weighing tendencies. Items 1-3 are summed to provide the approach weighing tendency subscale and items 4-6 are summed to provide the avoidance weighing tendency subscale, with scores ranging from 3-18. Higher scores on each subscale indicate a higher degree of that subscale's weighing tendency.

• Three Factor Eating Questionnaire (TFEQ) - Restriction subscaleChange from baseline assessed at screen visit to session 20 and post-treatment following final session, an average of 20-25 weeks after baseline assessment.

  An 18-item, self-report questionnaire that assesses the presence and severity of restriction.

• Eating Disorder Inventory-3 (EDI-3) - Drive for Thinness and Body Dissatisfaction subscalesChange from baseline assessed at screen visit to session 20 and post-treatment following final session, an average of 20-25 weeks after baseline assessment.

  Subscales from the self-report EDI-3 questionnaire that will be used to assess the presence of both drive for thinness and body dissatisfaction. The drive for thinness subscale is 7 items and body dissatisfaction subscale is 10 items.

• Clinical Impairment Assessment Questionnaire (CIA)Change from week one of study treatment to post-treatment following final session, an average of 25 weeks after week one (measured at weeks one, six, and twenty), and to one, three, and six-month follow-up sessions, up to 11 months after week one.

  A 16-item self-report measure of the severity of psychosocial impairment due to eating disorder features.

• Quality of life questionsChange from week six of study treatment to post-treatment following final session, an average of 25 weeks after week one (measured at weeks one, six, and twenty), and to one, three, and six-month follow-up sessions, up to 11 months after week one.

  A set of two qualitative questions, developed by the study team, which assess improvements in quality of life since starting treatment ("How has your life improved since beginning treatment?") and areas still needing improvement ("What areas of your life could still be improved?").