2 - (SYM23) Anhedonia, Depression, and Functions of Restrictive Eating in Anorexia Nervosa

Introduction: Anorexia nervosa (AN) is a debilitating psychiatric illness characterized by extreme dietary restriction leading to significant weight loss. Individuals with AN endorse elevated anhedonia beyond comorbid depression, and reward-based models of AN suggest that individuals with AN engage in restrictive eating to upregulate positive emotions in the context of global low positive affect. However, it is unclear how anhedonia and general depression symptoms may differentially relate to the processes that reinforce dietary restriction. Thus, understanding the connection between depressed mood, anhedonia, and specific operant functions of restrictive eating will provide critical insights that may improve interventions targeting these reinforcement processes.

Methods: Adult participants (n = 56) with AN (n = 18 with acute AN, n = 38 weight restored) completed the Functional Assessment of Restrictive Eating (FARE) scale, which assesses four sources of reinforcement from restrictive eating: automatic positive (e.g., “feel proud”), automatic negative (e.g., “relieve stress”), social positive (e.g., “get others to understand or notice you”), and social negative (e.g., “avoid being with others”). Participants also completed self-report measures of depression, pleasure, and social anhedonia. We used hierarchical linear regression with depression and BMI entered first and anhedonia measures second for each FARE subscale.

Results: Greater depressive symptoms were associated with increased automatic positive (b = .05, p < .001) and negative (b = .04, p < .001) reinforcement and social positive reinforcement (b = .02, p = .04) from restrictive eating, even when controlling for BMI and anhedonia. Anticipatory and consummatory reward and social anhedonia were not significantly associated with any of the FARE subscale scores when controlling for depression.

Conclusions: While prior research suggests that anhedonia is associated with more severe ED symptoms overall, these results indicate that global depression severity, rather than anhedonia specifically, may motivate reinforcement processes from restrictive eating. These findings applied to both acute and weight-restored AN, indicating that depression symptoms may play a role in restrictive eating beyond the short-term effects of malnutrition on mood. Notably, depression was associated with both positive and negative reinforcement from restrictive eating, indicating the importance of addressing both positive and negative emotion regulation in the treatment of AN.