Daily and momentary mood and stress are associated with binge eating and vomiting in bulimia nervosa patients in the natural environment.

The relation of mood and stress to binge eating and vomiting in the natural environments of patients with bulimia nervosa (BN) was examined using real-time data collection. Women (n = 131; mean age = 25.3 years) with BN carried a palmtop computer for 2 weeks and completed ratings of positive affect (PA), negative affect (NA), anger/hostility (AH), and stress (STRS); they also indicated binge or vomit episodes (BN-events) 6 times each day. Mixed models were used to compare mood and STRS between and within days when BN-events occurred. Between-days analyses indicated that binge and vomit days both showed less PA, higher NA, higher AH, and greater STRS than days with no BN-events. Within-day, decreasing PA, and increasing NA and AH, reliably preceded BN-events. Conversely, PA increased, and NA and AH decreased following BN-events. Demonstration of the temporal sequencing of affect, STRS, and BN-events with a large BN sample may help advance theory and clinical practice, and supports the view that binge and purge events hold negatively reinforcing properties for women with BN.