Enhanced CBT (CBT-E) is an effective treatment for the majority of outpatients with an eating disorder; however in about 30% of patients remission is made difficult. This may be due to the concomitant presence of trauma. Therefore we expect that a combination of CBT-E and EMDR, which is the evidence based treatment for PTSD disorder, would enhance the remission probability. This trial has a parallel group randomized controlled design. All patients who will enter in contact with the Regional Reference Centre for Eating Disorders in Verona and will satisfy inclusion criteria will be randomized to the broad form of CBT-E (CBT-Eb) plus EMDR or CBT-Eb alone. Patients will be evaluated before the treatment, at the end of treatment and after 6 months post-treatment with a set of standardized measure to assess eating disorder symptoms and other possible predisposing and moderating factors. The efficacy of CBT-E vs CBT-E + EMDR will be evaluated at the end of the treatment and after 6 months in terms of global score of the Eating Disorder Examination. Moreover the changes in other secondary outcomes will be considered. This explorative study may suggest new hypothesis for larger RCTs in order to increase the knowledge on ED.

Background. The Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM-5) distinguishes three broad categories of Eating Disorder (ED): anorexia nervosa (AN), bulimia nervosa (BN), and Other Specified Feeding or Eating Disorder (OSFED). The International Classification of Diseases tenth revision (ICD-10) also reports three categories: anorexia nervosa, bulimia nervosa, and atypical eating disorder.

Anorexia Nervosa (AN). Anorexia nervosa, which primarily affects adolescent girls and young women, is characterized by distorted body image and excessive dieting that lead to severe weight loss with a pathological fear of becoming fat. People affected by anorexia often go to great attempts to hide their behaviour from family and friends. Often people with anorexia have low confidence and poor self-esteem. They can see their weight loss as a positive achievement that can help increase their confidence. It can also contribute to a feeling of gaining control over body weight and shape. The illness can affect people's relationship with family and friends, causing them to withdraw; it can also have an impact on how they perform in education or at work. The seriousness of the physical and emotional consequences of the condition is often not acknowledged or recognised and people with anorexia often do not seek help.

Bulimia Nervosa (BN). Bulimia nervosa is a serious disorder that involves a recurring pattern of binge eating followed by dangerous compensatory behaviours in an effort to counteract or "undo" the calories consumed during the binge. Marked distress regarding binge eating is present. The binge eating occurs, on average, at least once a week for three months. People with bulimia often feel trapped in this cycle of dysregulated eating, and there is a risk for major medical consequences associated with bulimic behaviours.

Other Specified Feeding or Eating Disorder (OSFED). It is a feeding or eating disorder that causes significant distress or impairment, but does not meet the criteria for another feeding or eating disorder.

Treatment of Eating Disorders. Guidelines recommended that people with anorexia nervosa should first be offered outpatient treatment and that inpatient care be used for those who do not respond or who present with high risk and little psychosocial resources. Nevertheless the evidence base relating to the treatment of anorexia nervosa is meagre and no first line treatment is identified. Recommendations emphasise the importance of a multi-disciplinary approach including medical, nutritional, social, and psychological components. Among psychotherapies, CBT is one of the suggested treatment. For atypical eating disorders (eating disorders not otherwise specified), in the absence of evidence "it is recommended that the clinician considers following the guidance on the treatment of the eating problem that most closely resembles the individual patient's eating disorder". Regarding bulimia nervosa, CBT-BN is recommended as first-line treatment. CBT-BN has evolved over the past decade in response to a variety of challenges: its procedures have been refined, particularly those addressing patients over evaluation of shape and weight, and it has been adapted to make it suitable for all forms of eating disorder, thereby making it "transdiagnostic" in its scope. This implemented CBT treatment was defined Enhanced CBT. Several studies addressed the efficacy of CBT-E across several eating disorders. In detail, there are two possible CBT treatments for eating disorders, a simpler one, more focused on eating disorders features defined as focused form of Enhanced CBT (CBT-Ef) and another more complex, that addresses external psychopathological processes, named broad form of Enhanced CBT (CBT-Eb). This new version of the treatment also addresses psychopathological processes "external" to the eating disorder, such as clinical perfectionism, low self-esteem or interpersonal difficulties, which interact with the disorder itself.

Eating Disorders and Trauma History. There is evidence of an association among multiple episodes or forms of trauma, ED and the level of post-traumatic symptoms. Many studies have documented trauma history in patients with ED, with childhood sexual abuse being the most well-documented trauma in these patients. Other types of trauma reported in ED patients include physical and emotional abuse, teasing and bullying, and parental break-up and loss of a family member. A review emphasized that trauma histories are much more commonly associated with BN, AN binge-purge type, and EDNOS characterized by bulimic symptoms, such as binge eating disorder (BED) or "purging disorder," than with AN restricting type or EDNOS not associated with bulimic symptoms. Bulimic women had more psychopathology than non-bulimic women, and there is an association between the severity of comorbid psychopathology and the severity of trauma. It has been suggested that it is PTSD, rather than an abuse history per se, that best forecasts the emergence of BN. In addition, PTSD predicts comorbidity with major depression and alcohol abuse/substance dependence in conjunction with BN. PTSD prevalence in ED patients is about 24.3%, confirming the comorbidity between both disorders. It has been suggested that there is no significant difference between AN and BN patients with regard to the lifetime prevalence of trauma. Some authors underline that patients with higher PTSD symptomatology also suffer from more severe ED symptoms. As far as regards PTSD treatment, CBT with prolonged exposure, eye movement desensitization and reprocessing (EMDR), and pharmacotherapy have shown to be the most effective. EMDR is a psychotherapy that emphasizes disturbing memories as the cause of psychopathology. These memories and associated stimuli are inadequately processed and stored in an isolated memory network. The goal of EMDR is to reduce the long-lasting effects of distressing memories by developing more adaptive coping mechanisms. The therapy uses an eight-phase approach that includes having the patient recall distressing images while receiving one of several types of bilateral sensory input, such as side to side eye movements. The use of pharmacotherapy without concomitant psychotherapy is generally ineffective in terms of producing complete and lasting abstinence in ED patients. It is important to assess the mechanisms that functionally link disorders or problem behaviours together. This is particularly true for those with PTSD and other trauma-related comorbidity. In this respect, EMDR appears to easily complement the CBT for PTSD. EMDR has been shown to be as efficacious as CBT with prolonged exposure as well as treatment with fluoxetine. There are also some clinical reports which support the adoption of EMDR to treat ED.

Aim. The trial described here has the aim to compare, at the end of the treatment and at 6 months post-treatment, the efficacy of Eye Movement Desensitization and Reprocessing (EMDR) plus Broad Form of Enhanced Cognitive Behavioural Therapy (CBT-Eb) with that of Broad Form of Cognitive-Behavioural Therapy (CBT-Eb) alone in a sample of patients with Eating Disorders. We expect that EMDR plus CBT-Eb will ameliorate the severity of the eating disorder compared to CBT-Eb alone, primarily in patients with trauma history.

Design. The trial has a parallel group randomized controlled design, which compares, at the end of the treatment and after 6 months post-treatment, the efficacy of Eye Movement Desensitization and Reprocessing (EMDR) plus Broad Form of Enhanced Cognitive Behavioural Therapy (CBT-Eb) with that of Broad Form of Cognitive-Behavioural Therapy (CBT-Eb) alone in a sample of patients with Eating Disorders.

Participants. Study participants are recruited from the Regional Reference Centre for Eating Disorders operating for the Italian National Health Service in Verona. Those who satisfy inclusion and exclusion criteria and give written informed consent to participate in the study will be randomized to CBT-Eb plus EMDR or CBT-Eb alone.

Clinical assessment. At baseline, at the conclusion of the treatment and at 6 months post-treatment, patients will be assessed by the following set of standardized instruments:

• Eating Disorder Examination (EDE)
• Hopkins Symptom Checklist (SCL-90)
• Eating Disorders Inventory (EDI.3)
• Barratt Impulsiveness Scale (BIS-11)
• Level of Expressed Emotion (LEE)
• Young Schema Questionnaire (YSQ)
• Penn State Worry Questionnaire (PSWQ)
• Rathus Assertiveness Scale (RAS)
• Clinical Impairment Assessment Questionnaire (CIA)
• Semi-structured Interview for Eating Disorder (ISDA)
• Parental Bonding Instrument (PBI)
• Childhood Experience of Care and Abuse Questionnaire (CECA-Q)
• Family History Screen
• Tridimensional Personality Questionnaire (TPQ)
• Impact of Event Scale - Revised (IES-R)
• Inventario degli Eventi Stressanti e Traumatici della Vita
• Global Assessment of Functioning (GAF)
• Dissociative Experience Scale (DIS-Q)
• Toronto Alexithymia Scale (TAS-20)
• Hypomania/Mania Symptom Checklist (HCL-32)
• Scheda ad hoc sugli interventi ricevuti. Randomization procedure. 40 patients will be allocated to CBT-Eb plus EMDR treatment and 40 patients to CBT-Eb treatment alone. Patients will be randomly assigned to one of the two trial arms with a 1:1 allocation rate. Stratified randomization will be performed to balance differences in patients' characteristics [trauma (yes vs no) and BMI (<=17.5 vs >17.5)].

Sample size and power calculations. A total of 80 patients (40 patients per treatment condition) will detect a difference in terms of global EDE score of 0.64, with a power of 80% (two-side t test at 0.05), assuming a standard deviation of global EDE score of 1.0. The sample size has been estimated by using PASS 11.

Statistical analysis. Statistical analysis will be based on an intention-to-treat (ITT) basis, comparing outcomes from all patients allocated to the two trial arms. The ITT principle will allow for potential biases arising from loss to follow-up, under the assumption that missing outcomes are missing at random (MAR). Findings will be reported according to the CONSORT guidelines for parallel group randomised trials.

Inclusion Criteria:

• Age between 14 and 45 years
• Diagnosis of Eating Disorder that meets DSM 5 diagnostic criteria for Anorexia Nervosa (AN), Bulimia Nervosa (BN) or Other Specified Feeding or Eating Disorder (OSFED)
• A clinical severity which permits to treat the person at out-patient level

Exclusion Criteria:

• Eating Disorder of high clinical severity, not treatable at out-patient level
• Comorbidity with psychotic symptoms or any other DSM 5 disorder which might hinder eating disorder treatment
• Medical conditions which might impede data interpretation (chemotherapy, pregnancy status)
• Substances use and abuse
• Having previously received an evidence-based CBT treatment for the same eating disorder and/or EMDR