Overgeneralization of Conditioned Fear as a Pathogenic Marker of Anorexia Nervosa

Anorexia nervosa is a chronic mental health condition characterized by maladaptive food consumption (i.e., hypophagia) and distorted body image. There is substantial evidence of a phenotypic overlap between anorexia nervosa and anxiety disorders, as well as data suggesting the two share a common genetic pathway. Despite these findings, little research has examined fear conditioning among individuals with anorexia nervosa, and no research has examined whether individuals with anorexia nervosa have a propensity to overgeneralize conditioned fear stimuli, one of the more robust fear-conditioning markers of anxiety disorders. The current study assesses generalization of conditioned fear with fear-potentiated startle: the cross-species enhancement of the startle reflex when an organism is in a state of fear. Animal data, as well as an emerging literature in humans, tightly links fear-potentiated startle to the amygdala-based fear circuit. Thus, evidence of overgeneralized fear-potentiated startle in anorexia nervosa would link this eating disorder to hypersensitivity of the fear circuit and could inform the development of novel pharmacologic and psychological treatments for anorexia nervosa based on treatment models used in the anxiety disorders literature.

The overarching objective of the current proposal is to examine the feasibility of applying a generalization of conditioned fear-potentiated startle paradigm, which has been used successfully to measure the sensitivity of fear networks in anxiety disorders, to adults with anorexia nervosa. The specific aim will be to examine whether conditioned-fear generalization gradients in anorexia nervosa participants differ from those in healthy controls. It is hypothesized that anorexia nervosa participants will display stronger generalization as indicated by less quadratic generalization gradients (i.e., a more gradual decline in conditioned fear as the generalization stimuli deviate from the conditioned fearful stimuli), which is indicative of a heightened sensitivity, or lower thresholds of activation, in the fear circuit (i.e., less danger information necessary to trigger the fear).