Delay Discounting of Reward and Impulsivity in Eating Disorders: From Anorexia Nervosa to Binge Eating Disorder.

Evidence points to eating disorder patients displaying altered rates of delay discounting (one's degree of preference for immediate rewards over larger delayed rewards). Anorexia nervosa (AN) patients are believed to have an increased capacity to delay reward, which reflects their ability to override the drive to eat. Contrarily, binge eating disorder (BED) patients are associated with a reduced predisposition to delay gratification. Here, we investigated monetary delay discounting and impulsivity in 80 adult women with EDs (56 AN and 24 BED), diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria, and 80 healthy controls. AN-restrictive (AN-R) subtype patients showed less steep discounting rates than BED and AN-bingeing/purging subtype patients. Compared with healthy controls and AN-R patients, BED and AN-bingeing/purging patients presented higher delay discounting and positive and negative urgency levels. Our findings suggest that restriction in AN-R patients is associated with disproportionate self-control, whereas bingeing behaviours could be more driven by emotional states and impulsivity traits. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.