Virtual Environments For Supporting Obesity Treatment (AVATOB)

Participants 60 Patients seeking treatment at the Obesity Unit of the Medica Sur Hospital in México City, Mexico. Informed consent to participate will be aleatory assigned to a three different conditions.

Procedures In the initial interview, prospective participants will be provided with detailed information about the study and the treatments. All patients included in the study will be randomly assigned to the one (N=20) of the three treatment conditions described below, all conducted on an inpatient basis. The duration for all treatments will be 6 weeks and will be administered by two chartered clinical psychologists and one chartered psychotherapist under the supervision of a senior chartered psychotherapist. The three therapists will be balanced among the three conditions.

1. Nutritional groups In this condition (NT) the participants (N=20) subjects enter only 5 weekly nutritional groups held by dieticians based on the LEARN manual (Brownell, 1985), whose goal will be to provide practical guidelines for the self-monitoring of eating and lessons on nutrition (e.g stressing gradual weight loss with the caloric restriction achieved largely by reductions in fat intake), plus a low-calorie diet (1,200 kcal/day) and physical training (30 min of walking two times a week as a minimum).

2. Cognitive-Behavioral therapy CBT group (N=20) will be based on the same treatment proposed in the first condition plus 15 additional sessions over 6 weeks.

   Therapists will follow a detailed manual that outlined the content of each session. This manual was based on the cognitive—behavioral treatment approach described by Cooper and colleagues (Cooper & Fairburn, 2002; Cooper et al., 2003). It was developed during a year of intensive pilot work and adapted to the in-patient setting. Patients will be taught to self-monitor their food intake and eating patterns and thoughts, as well as the circumstances and environment surrounding eating (e.g. whether eating alone or with others, speed of eating, and place of eating). Patients will also be taught to identify problems in eating, mood, and thinking patterns and to gradually develop alternative patterns.

   In particular, after the first week the patients will enter 5 weekly group sessions aimed at addressing weight and primary goals, and 10 biweekly individual sessions aimed at establishing and maintaining weight loss, addressing barriers to weight loss, increasing activity, addressing body image concerns and supporting weight maintenance.

3. Experiential Cognitive therapy Experiential CT group (N=4) involved the same treatment proposed in the first condition plus 15 additional sessions over 4/6 weeks.

In the sessions we will use the "20/20/20 rule". During the first 20 minutes, the therapist focus on getting a clear understanding of the patient's current concerns, level of general functioning, and the experiences related to food. This part of the session tends to be characterized by patients doing most of the talking, although therapist guides with questions and reflection to get a sense of the patient's current status. The second 20 minutes is devoted to the virtual reality experience. During this part of the session the patient enters the virtual environment and faces a specific critical situation (Kitchen, Supermarket, Pub, Restaurant, Gymnasium, etc.). Here the patient is helped in developing specific strategies for avoiding and/or coping with it. In the final 20 minutes the therapist explores the patient's understanding of what happened in VR and the specific reactions - emotional and behavioral - to the different situations experienced. If needed, some new strategies for coping with the VR situations are presented and discussed. To support the empowerment process, the therapists follow the Socratic style: they use a series of questions, related to the contents of the virtual environment, to help clients synthesize information and reach conclusions on their own.

In accordance with informed consent, assessments will be obtained before treatment, at posttreatment, 3 and 6 months after the treatment conclusion.