Is restrictive eating behavior in anorexia nervosa short-sighted? An experimental investigation

About This Grant

PROJECT SUMMARY Anorexia nervosa (AN) is a devastating eating disorder that has severe effects on mental and physical health, and one of the highest mortality rates of any psychiatric disorder. AN is characterized by persistent restriction of food intake below the body’s needs, and particular restriction of dietary fat, leading to relapse following treatment to restore weight. Maladaptive choices about what to eat are remarkably resistant to treatment in AN, even among patients expressing desires for long-term recovery. Decision making is guided by a valuation process in which the ventromedial prefrontal cortex (vmPFC) encodes a value signal that represents individual preference for a given choice option. The ability to assign value to choices that are aligned with longer-term goals, but which do not confer immediate benefit, is supported by the vivid imagination of future scenarios, or episodic future thinking (EFT), and the effects of EFT on valuation are related to connectivity between the hippocampus and vmPFC. Recovery is a future outcome of eating energy-dense foods in AN, which in the short-term may be unpleasant. In this study we will begin to address the question of whether underuse of EFT during food choice contributes to the misalignment between goals of recovery and restrictive eating behavior among treatment-seeking patients with AN. Patients with AN and normal-weight healthy controls will complete a food decision making task in which they rate their preference to eat a range of items as a snack, while undergoing functional MRI scanning. The task is completed under two conditions (order randomized and counterbalanced): EFT, in which participants are oriented toward a personalized future event; and standardized episodic thinking (SET), in which participants are oriented toward a recent past event (playing video games). We will compare the effect of EFT versus SET manipulations, relative to no manipulation, among individuals with AN and HC across behavioral (preference for high-fat foods) and brain (functional connectivity between the hippocampus and vmPFC) levels. Findings from this study will identify 1) whether EFT ameliorates restrictive eating in AN; 2) whether patients with AN are able to recruit the neural circuits supporting EFT during valuation; 3) whether recruitment of these neural circuits is associated with the behavioral effects of EFT. A monetary decision task will be administered to compare the effects and mechanisms of EFT between AN and HC groups (normal-weight HC are not expected to change food preferences due to an EFT manipulation). Exploratory analyses will compare EFT ability and general future orientation between AN and HC groups, and examine the relationship between EFT ability, effects of the EFT manipulation, and clinical characteristics, in the AN group. This developmental study will provide preliminary data for large-scale investigation into the role of disturbances in EFT in AN pathology and interventional research targeting future thinking to improve eating behavior among patients with AN.