Extreme weight conditions impact on the relationship between risky decision-making and interoception.

Anorexia nervosa (AN) and obesity (OB) lie on the two ends of the broad spectrum of extreme weight conditions (EWC). Both disorders entail the constant risk to one's body integrity. Importantly, risk-taking is supported by internal signals, the perception of which is typically distorted in EWC. In this study, we sought to characterize in EWC: (i) risky decision-making by contrasting situations in which people process bodies or neutral objects and (ii) the relationship between interoceptive ability and risky decision-making. In a between-subject design, participants with AN restricting type, participants with class 2 OB, and two groups of matched healthy controls (HC) (total N = 160) were administered either the Balloon Analogue Risk Task (BART) or a modified version of it by using a body-related stimulus as a cue in the place of the balloon. Moreover, we collected a measure of interoceptive sensibility and a measure of interoceptive accuracy. Results showed that, when analysing the global population as a continuum based on the BMI, the risk propensity decreased as a function of increased BMI, only for the task involving a body-related stimulus. Moreover, while HC risk propensity toward a body-related stimulus correlated with interoceptive sensibility, such correlation was absent in participants with AN. Individuals with OB, on the opposite pole, showed mixed interaction between interoception and risky decision-making in both tasks. These findings add one more tile to understanding these complex pathologies in the EWC spectrum, opening up future differential rehabilitation scenarios.