(PS6-A12) Preliminary Data That Psychological Treatment and Higher Baseline Anxiety Are Associated with Decreases in Postprandial Fullness for Individuals with Bulimia Nervosa-spectrum Disorders

Gastrointestinal symptoms, particularly postprandial fullness, are frequently reported in bulimia nervosa and other weight and shape-oriented eating disorders. They are hypothesized contribute to eating disorder maintenance as individuals engage in disordered behaviors (e.g., purging) to avoid uncomfortable sensations. Limited data exist evaluating how these symptoms change in response to outpatient psychological treatment for bulimia nervosa-spectrum disorders. The current study sought to describe the course of postprandial fullness and early satiation across psychological treatment for adults with bulimia nervosa-spectrum disorders and to test if baseline anxiety moderates treatment response. Secondary data analysis was conducted on questionnaire data provided by 30 individuals (80% white, M(SD) age = 31.43(13.44) years; 90% female) throughout treatment and at six-month follow-up in a pilot trial comparing mindfulness and acceptance-based treatment with cognitive-behavioral therapy. Participants completed assessments at baseline, four sessions, twelve sessions, twenty sessions, and six month follow-up.  Both postprandial fullness (p < .001; Cohen’s d = 1.54) and early satiation (p < .001, Cohen’s d = 1.23) significantly decreased across time. Baseline trait anxiety moderated changes in postprandial fullness (p = .02), such that greater decreases in postprandial fullness (Estimate = -1.614) were observed for those with higher baseline trait anxiety compared to those with lower baseline trait anxiety (Estimate = -.746). Baseline trait anxiety did not moderate changes in early satiation across time (p = .22), although greater baseline trait anxiety was associated with higher overall levels of early satiation (Estimate = .10, p = .005). Results extend prior work by demonstrating that postprandial fullness and early satiation decrease with outpatient psychological treatment for bulimia nervosa-spectrum disorders. Baseline anxiety moderated this effect for postprandial fullness, suggesting that postprandial fullness may have heterogeneous etiologies among patients with bulimia nervosa. Changes in anxiety may be an important mechanism of change in eating disorder treatment. In contrast, trait anxiety was associated with overall high levels of early satiation but did not moderate outcomes. Future work should continue to evaluate both psychological (anxiety) and physiological (delayed gastric emptying) as causes of gastrointestinal symptoms to inform treatment development and refinement.