Eating Disorders (ED) constitute a serious public health issue that affects predominantly women and appears typically in adolescence or early adulthood. ED are extremely difficult to treat as these disorders are ego-syntonic and many patients do not seek treatment. As ED are associated with significant adverse medical and psychological consequences, it is vital to focus on the development of successful prevention programs. Even though, in the last two decades significant steps have been made over the development of efficacious and effective ED prevention programs, there is room for improvement in regards to effect sizes. Prevention programs for ED to date have focussed on either reducing the pursuit of the thin ideal or on disputing and replacing unrealistic thoughts with regard to food, body and weigh. There is a growing body of evidence supporting the functional relationship between ED symptomatology and control of emotional states either by avoiding or inhibiting emotional responses. The present study aimed to investigate the effectiveness and acceptability of a digital Acceptance and Commitment Therapy (ACT) based prevention program in comparison to a wait-list control group for young women identified to be at risk for ED. The goals of the study were to describe the development of the AcceptME protocol and digitalized program, assess participants' feedback and the acceptability of the program, and examine the effectiveness of the ACT-based prevention program compared to a wait-list control group. This prevention program has several innovations: a) it is based on ACT theory and practices; b) it uses gamification principles to create a program appealing to adolescents; c) it targets behaviour change in individuals via helping a digital character overcome difficulties in the digitalized program.

Eating Disorders (EDs) constitute a serious public health issue that affects mainly women and appears typically in adolescence or early adulthood. EDs often result in serious physical health consequences as well as enduring psychological difficulties and behavioral complications. Prevention of EDs is paramount as it will reduce such adverse effects, improve the quality of the patient's and his/her family's life and decrease costs incurred by EDs. To date, prevention approaches have not been uniformly effective for EDs and as a consequence there is great room for improvement. There is a growing body of evidence supporting the functional relationship between EDs symptomatology and controlling emotional states either by avoiding or inhibiting the emotional response. Furthermore, theories support that AN begins with a general need of self control and not just emotional control. Current prevention programs for EDs have largely ignored on the problem concerning self-control. This study will propose a new prevention program based on the cognitive-behavioral theory, which suggests that one of the main features of anorexia is a general need of self-control, and the psychological inflexibility theory, which suggests that this need of experiential control may lead to a broader state of psychological inflexibility. A prevention program based on mindfulness, acceptance and change is hypothesized to be able to target ineffective control strategies in individuals at high-risk for developing EDs, prior to the disorder manifesting itself. A treatment which is based on mindfulness and acceptance is Acceptance and Commitment Therapy (ACT), a 3rd wave CBT that targets ineffective control strategies and inflexibility found in a range of psychopathology problems. This study will apply an ACT based prevention program for EDs in an internet based delivery modality delivered to high-risk individuals. The hypotheses made are the following: participants receiving the prevention program will 1) develop greater body image flexibility, 2) decrease their control behaviours (e.g. dieting, exercising, body image avoidance behaviors), and 3) have significantly fewer ED symptoms, decreased body dissatisfaction, decreased risk for developing EDs and have significantly higher quality of life, as compared to the wait-list control group at the end of prevention and at 1-month follow up. We also hypothesized that changes in ACT-related process measures (defusion, mindfulness, values, willingness, body image flexibility, self as context) will mediate improvements in EDs outcome measures (eating disorder risk, eating disorder symptoms, dieting, exercising, body image avoidance behaviour). For the purposes of the study, high-risk participants developing EDs will be recruited from high schools and vocational schools. Participants will be randomly assigned either to the internet-based ACT intervention or the wait list control group. Participants will complete process and outcome measures at baseline, post treatment and follow-up. Results will be then analyzed and conclusions will be made. Repeated measures MANOVA will be used to assess the changes and the differences between the prevention group and the wait list control group. Furthermore, to assess whether ACT variables such as values, mindfulness, defusion, self as context, willingness will mediate ED symptoms mediation analysis will be used.

Inclusion Criteria:

• females
• aged 13-25 years,
• voluntary participation and parental consent for ages lower than 18 years,
• good working knowledge of the Greek language and
• report a score of greater that 52 at the Weight Concern Scale (Killen et al., 1996) thus, indicating that they are at high risk for developing ED.

Exclusion Criteria:

• not meeting inclusion criteria

Female

No masking was carried out