Intact delay discounting but more optimal reward-based decisions in anorexia nervosa during an experiential task

Individuals with anorexia nervosa (AN) have an apparent increased capacity to delay gratification and forgo immediate food rewards in their long-term pursuit of thinness. Prior research probed this capacity using delay discounting tasks that assess how rapidly the subjective value of rewards decreases as a function of time until receipt. However, significant effects in AN were mostly subtle or absent using traditional tasks. Here, we tested whether altered delay discounting might be revealed in AN during an experiential gamified task.

Eighty acutely underweight females with AN and pairwise age-matched female healthy controls (HC) made binary choices moving an avatar to collect rewards of varying magnitudes and distances. The presence of an overall time limit rendered one choice optimal (i.e. higher cost-benefit ratio) in each trial. We tested group differences in delay/distance discounting and used signal detection theory to determine whether decision patterns were due to inherent preferences (e.g. for immediate rewards) or acuity to detect optimal choices.

No group differences in delay discounting parameters were found, but participants with AN favored smaller, closer rewards when this was the optimal strategy. This was neither related to an a priori bias toward immediate/delayed rewards nor enhanced choice acuity.

Even in a more realistic experiential task, individuals with AN did not exhibit reduced delay discounting. Instead, because choosing the closer option more frequently required more decisions overall, our findings may reflect increased task engagement and align with the notion of greater willingness to exert effort for reward in AN.