Interoception Moderates the Association Between Reward Sensitivity and Suicide Attempt History in Patients with Anorexia Nervosa

Abstract Background Anorexia nervosa (AN) carries elevated suicide risk through poorly understood mechanisms. This study examined whether interoception and reward sensitivity, each separately implicated in suicide risk in AN, interact in relation to suicide attempt (SA) history. Methods 160 patients with AN (Mage: 26 ± 10 years; 94% female) were assessed for interoceptive awareness (IA) deficits (EDI-2) and reward sensitivity (SPSRQ), alongside lifetime SA history and clinical covariates. Moderated logistic regression tested the IA × reward sensitivity interaction on SA history, adjusting for confounders and applying Lasso regularization. Results Lifetime SA history was reported by 22% (N = 34) of patients. SA history was positively associated with IA deficits (OR = 1.71, 95% CI [1.25, 2.50], p = 0.002) and reward sensitivity (OR = 1.22, 95% CI [1.09, 1.41], p = 0.002), with significant interaction between them (OR = 0.99, 95% CI [0.98, 1.00], p = 0.003). Higher reward sensitivity predicted greater SA odds only among patients with relatively preserved IA; no association emerged among those with greater deficits. The interaction remained significant after adjusting for disorder duration and severity, alcohol/substance use disorder, and childhood trauma, and after regularization. Conclusions IA deficits moderated the reward sensitivity-SA relationship in AN. Reward-related mechanisms may contribute to suicidal behavior specifically among patients with preserved interoception, supporting individualized risk assessment integrating interoceptive and reward processes. Replication is needed. Trial registration: ClinicalTrials.gov: NCT03160443