Page 154 - The efficacy and effectiveness of psychological treatments for eating disorders - Elske van den Berg

154 Chapter 8
This thesis considers the effectiveness of psychological treatments for adults with anorexia nervosa, bulimia nervosa and binge eating disorder, and, as it is can occur in individuals who are morbidly obese, the effectiveness of psychological interven- tions for eating disorder pathology.
Obesity, defined as an abnormal or excessive fat accumulation, is not included as a psychiatric disorder in the DSM-5 eating disorder section, as obesity itself is not necessarily caused by a psychological dysfunction (Hoek & van Elburg, 2014).
Eating disorders affect both mental and physical well-being of patients (Royal Australian and New Zealand College of Psychiatrists, 2014), this also applies to being (morbidly) obese (Luppino et al., 2010). Obesity is firmly associated with an increased risk of depression, obese women are, in particular, more likely to experience a mood disorder (Luppino et al., 2010). With regard to eating pathology, literature suggests that 30% of obese individuals seeking weight control treatment might be diagnosed with a binge eating disorder (de Zwaan, 2001; Meany, Conceição, & Mitchell, 2014). In obese individuals opting for bariatric surgery, findings indicate a pre-operative prevalence of axis I disorders between 27% and 42%, mainly consisting of affective disorders, anxiety disorders and eating disorders (Herpertz et al., 2004).
Although anorexia nervosa is a relatively rare disorder in many non-western countries, bulimia nervosa and binge eating disorder are common disorders around the world (Hoek, 2016). Worldwide, the prevalence of obesity (having a body mass index over 30 kg/m2) has nearly tripled since 1975, the proportion of individuals with morbid obesity (having a body mass index over 40 kg/m2) is a small fraction of all individuals with obesity (NCD Risk Factor Collaboration, 2016).
Treatment outcome is poor for eating disorders, around 30% of patients with anorexia nervosa are estimated recover in the first decade of the disorder (Wonder- lich, Bulik, Schmidt, Steiger, & Hoek, 2020). For bulimia nervosa and for binge eating disorder, remission rates range from 22% to 68% (De Jong, Schoorl, & Hoek, 2018). For morbid obesity, non-surgical interventions have proven to be ineffective in the long run, so weight loss surgery has been suggested as the most effective weight loss method. Although the majority of patients achieves successful weight loss after surgery, 20-30% experience suboptimal weight loss (Livhits et al., 2011). Literature suggests an association between this suboptimal weight loss and psychological and behavioral factors (Wimmelmann, Dela, & Mortensen, 2014).
This thesis consists of three parts. Part I examines the efficacy of psychologi- cal treatments for anorexia nervosa. Part II examines the differential effectiveness and the cost-effectiveness of Cognitive behavioral therapy-Enhanced, a specialized psychological treatment compared with treatment-as-usual, for patients with bulimia