(PS14-81) Reward Dysfunctions Are Associated with Suicidal Thoughts and Behaviors in Anorexia Nervosa

Anorexia nervosa (AN) is a debilitating mental illness that is highly comorbid with suicidal thoughts and behaviors (SITBs). While previous studies have suggested that altered reward processing is central to the pathology of AN, there remains a limited understanding of the involvement of reward dysfunctions in SITBs in individuals with AN. Thus, our study aimed to investigate whether individuals with AN and SITBs exhibit dysfunctions in different facets of reward processing and whether these traits account for the relationship between restrictive eating and the severity of SITBs. For this aim, we examined self-reported social anhedonia and anticipatory and consummatory reward experiences using Revised Social Anhedonia Scale and Temporal Experience of Pleasure Scale in three groups: individuals with AN with lifetime SITBs (AN+SITB group, n=31), individuals with AN without lifetime SITBs (AN-SITB group, n=27), and healthy controls (HC group, n=33). The severity of SITBs, which were assessed by SCID-IV by summing the values of suicidal ideation, self-harm, and suicide attempt, were converted to binarized values for group categorization. A three-group ANCOVA was conducted to examine potential group differences in self-reported social anhedonia and anticipatory and consummatory reward, beyond and above the effects of depression. Additionally, within the AN group, mediation analysis with bootstrapping assessed whether reward dysfunctions played a mediating role in the association between the severity of self-starvation drive and the severity of SITBs. Our findings revealed that individuals in the AN+SITB group exhibited significantly greater social anhedonia and lower anticipatory reward experiences in comparison to both the AN-SITB and HC groups, with the effect of social anhedonia persisting even after adjusting for depression (all ps < .05). Furthermore, social anhedonia fully mediated the link between self-starvation drive and the severity of SITBs (b = 0.15, 95% CI = [0.004, 0.354]). Taken together, our study suggests that reward dysfunctions may serve as a substantial risk factor for SITBs in AN, beyond the influence of depression. Addressing impairments in reward processing, especially the diminished capacity to derive pleasure from social interactions or relationships, could be pivotal in treating SITBs in individuals with AN.