Eating Disorders in obese patients seeking bariatric surgery: aspects of mental health before and afterweight-loss treatment
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Background: An increasing number of obese patients are seeking surgical weight-loss treatments. Health-care workers need more knowledge about the various characteristics of these patients, and how they should be treated. Prior to bariatric surgery, those with Eating Disorders (EDs) showed impaired psychological functioning in several areas when compared with those without EDs. Some studies have shown that patients with EDs also have less success in the weight loss interventions. The present thesis will investigate the various categories and sub-categories of EDs, and explore what characterizes the mental health of obese patients with comorbid EDs. Furthermore, the effects of the various pre-treatment EDs both before and after surgical and conservative weight-loss treatments were studied with regard to mental health. Objectives:To assess which EDs are present in the obese patients waiting for bariatric surgery, and the prevalence of their diagnoses. Before the treatment, patients with and without EDs were compared in regard to psychological, somatic, and demographic variables.To investigate the possible relations between subthreshold EDs (lacking one criterion for the binge eating disorder) and their levels of psychological distress.To assess whether pre-treatment EDs negatively affect the psychological distress and the weight loss of patients completing weight-loss treatments, bariatric surgery, or conservative treatment.Methods: Two populations were studied; some patients appeared in both. The first consisted of obese patients waiting for bariatric surgery n = 160, 117 (73%) women, 43 (27%) men. They were studied cross-sectionally. The second population consisted of 211 obese patients, of which 158 (74.9%) were women and 53 (25.1%) were men. They were studied in a pre-test post-test design with assessments before treatment, and again one year after treatment. The assessments were based on self-reports. Eating disorders were detected using Eating Disorders in Obesity (EDO), depression and anxiety using Hospital Anxiety and Depression Scale (HADS), and the personality trait, neuroticism using Eysenck Personality Questionnaire (EPQ-12). Factual data about demographics, BMI, obesity onset and obesity related somatic diseases were captured in a separate questionnaire. At the outset, all patients included in the studies were referred to bariatric surgery and selected using the same inclusion criteria: BMI between 35 and 40 plus at least one obesity-related somatic comorbidity; or BMI over 40. The patients in the second population were given the option to remain on the waiting list for surgical treatment, or to be enrolled into a conservative treatment program. Results: In the first population (n=160), 17.8% fulfilled the DSM-IV-TR criteria for ED. In total, 32.5% were identified with ED plus subthreshold ED by the chosen approach. No gender differences in socio-demographic variables, BMI, obesity onset, and obesity-related somatic diseases emerged. With the exception of age, no differences were found in these variables between those with and without EDs. However, the patients with ED were 4.4 years older than those without. At pre-test, the patients with ED presented with significantly higher levels of depression, anxiety and neuroticism than those without EDs. Likewise, more HADS-cases for depression and anxiety were found in those with EDs. Patients with sub-diagnostic binge eating disorders (SBED; called BE in paper I) reported significantly more depression and neuroticism, and they had higher numbers of HADS-cases of depression than those without ED. No significant differences in psychological distress were found for gender, high/low age, or high/low BMI using the median split. After bariatric surgery, the patients with EDs at pre-test demonstrated significantly less reduction in their levels of anxiety than the patients without EDs. The same was indicated as a statistical trend in patients undergoing conservative treatment. For depression, neuroticism and weight, no significant differences were found in the changes from pre-test to post-test between patients with and without EDs in any of the treatments. Discussion: This thesis details the current knowledge about EDs in obese pre-surgery patients by presenting the prevalence of all the DSM-IV EDs. When all diagnoses are included, about one third of the obese pre-surgery patients have EDs, which is in line with the findings of others. Nevertheless, differentiating between EDs in the screening of this patient group suggests that some patients with EDs (EDNOS) may not be identified as with EDs, by the widely used criteria for Binge Eating Disroder (BED). In regard to factors that may differentiate obese pre-surgery patients with EDs from those without EDs, a new finding was indicated, i.e., the personality trait, neuroticism was more pronounced in the patients with EDs. This finding supports the suggestions of previous reports that patients with EDs form a sub-group within the patient population showing more psychological distress before surgery. The same seems to be the case for patients with subthreshold ED. One year after the weight-loss treatments, the patients with EDs still had more psychological distress than those without ED. This indicates that weight reduction alone did not neutralize the differences in psychological distress usually found before treatment between patients with and without EDs. Patients with EDs also showed less reduction in anxiety symptoms after surgery than those without EDs. A clinical implication is that reducing the weight of patients with EDs may not be sufficient treatment of anxiety. Patients with EDs seem to be in need of additional interventions to improve their psychological functioning. This finding supports the use of pre-surgical screening for EDs.