Psychological predictors of outcome after gastric banding for morbid obesity

Abstract

Obesity has become a major public health problem in Western societies. Although surgery is considered the treatment of choice in morbid obesity, the outcome is variable and weight regain may occur in the long-term postoperative period. The aim of this thesis was to examine psychological predictors of treatment outcome after Laparoscopic adjustable gastric banding (LAGB) for morbid obesity. LAGB is a purely restrictive form of bariatric surgery designed to induce weight loss by limiting food consumption. The thesis consists of seven studies (five cross-sectional and two prospective), which are described in three parts: psychosocial outcome (chapter 2), general psychological predictors (chapters 3 and 4), and specific behavioral predictors and related determinants (chapters 5, 6, 7, and 8). The main aim of chapter 2 was to examine the short-term and long-term physical, mental, and particularly social quality of life in patient with severe obesity following LAGB. It was concluded that, in comparison with patients before surgery, patients after surgery felt and functioned better on physical and psychological dimensions of quality of life, and on most aspects of social quality of life. The purpose of the prospective study in chapter 3 was to examine whether personality traits predict short-term weight loss and, specifically, long-term weight loss maintenance after LAGB. Chapter 4 cross-sectionally examined the relationship between reported childhood sexual abuse and weight and health outcome after LAGB. The results in this thesis show that the general psychological predictors personality characteristics and childhood sexual abuse are not major predictors of outcome after bariatric surgery. Chapter 5 cross-sectionally analyzed binge eating and eating characteristics of a relatively large patient group with both short- and long follow-up duration after LAGB, while chapter 6 prospectively analyzed preoperative binge eating behavior and depression as predictors of weight outcome relatively short-term after LAGB. Our prospective study shows that preoperative binge eating, depression, and combined binge eating and depression, did not predict a worse weight outcome after LAGB. However, postoperative binge eating was associated with a worse weight outcome. Moreover, in chapter 7 binge eating was indicated to be a possible mediator between eating attitudes and weight and mental health outcome, whereas physical exercise was not a crucial mediator between exercise beliefs and outcome. Finally, chapter 8, focusing on cortisol and binge eating, shows that no differences in morning cortisol levels between patients with and without binge eating disorder were found, however, patients with binge eating disorder had lower total daytime cortisol levels than patients without binge eating disorder, and the magnitude of this difference was large. In conclusion, in terms of the predictive strength of postoperative outcome from preoperative psychosocial factors, this thesis provides no reason to exclude specific subgroups of morbidly obese patients from the operation or to give additional preoperative psychosocial care to specific subgroups of patients. Instead, the findings of this thesis suggest that the identification of individual patients requiring extra psychosocial care could better take place after the operation, with attention focused upon patients with binge eating problems.