Interoceptive Anxiety and Body Representation in Anorexia Nervosa.

Sahib S Khalsa,Michelle G Craske,Michael Strober,Jamie D Feusner,Armen C Arevian,Mahlega S Hassanpour

doi:10.3389/fpsyt.2018.00444

Abstract

Individuals with anorexia nervosa (AN) typically display anxious traits prior to the onset of food avoidance and weight loss that characterize the disorder. Meal associated anxiety is an especially common clinical feature in these patients, and heightened sensitivity to sympathetically mediated interoceptive sensations has also been observed. However, it remains unclear how heightened interoceptive sensitivity relates to experiences of anxiety before and after meals. To investigate this relationship, we experimentally induced anxiety and panic symptoms with isoproterenol, a peripheral sympathetic agonist similar to adrenaline, across several different conditions: during panic provocation, during anticipation of a 1,000 Calorie meal, and after meal consumption. Fifteen AN and 15 age- and sex-matched healthy comparisons received bolus infusions of isoproterenol and saline in a double-blinded, randomized design. Participants rated anxiety symptoms after each infusion, completed panic rating scales, and traced the location of perceived palpitations on a manikin to index interoceptive “body map” representation. The AN group reported significantly elevated anxiety relative to healthy comparisons during infusions before and after the meal, but surprisingly, not during panic provocation. These symptoms were accompanied by geographical differences in patterns of perceived heartbeat sensations across each condition. In particular, the AN group localized heartbeat sensations disproportionately to the chest during meal related saline infusions, when no cardiorespiratory modulation actually occurred. The AN group also showed a trend toward higher panic attack rates during the meal anticipation period. Correcting for anxiety levels reported during saline infusions abolished group differences in anxiety change across all conditions, suggesting a significant contribution of anxious traits in AN. The observation of meal related “visceral illusions” provides further evidence that AN is associated with abnormal interoceptive representation of the heartbeat and suggests that meal consumption, particularly when anticipated, preferentially alters the processing of interoception related signals in AN.

Highlights

Individuals with anorexia nervosa (AN) often exhibit heightened anxiety well before the onset of food avoidance and weight loss that characterize the disorder [1], and anxious traits are frequent precursors to the morbid diagnostic characteristics of AN [2,3,4]
It is presently unclear to what extent subjective experiences of anxiety reported by individuals with AN are primarily due to anxious traits, or whether they are exaggerated by aversive anticipation, and if so, whether aversive anticipation is generalized or is selectively modulated by specific contexts such as hypervigilance toward food cues [15, 16], intolerance of uncertainty [11], or discomfort with bodily sensations [17]
We considered three questions: [1] Does the peripheral modulation of interoceptive sensation with isoproterenol disproportionately increase subjective anxiety associated with meal presentation in AN? [2] Is there a greater panic inducing effect of isoproterenol infusions in AN, irrespective of meal proximity? [3] Is there accompanying evidence of abnormal mapping of bodily sensation that would indicate a disturbance of interoceptive representation in AN? In regard to the first question, we predicted that individuals with AN would display greater isoproterenol-induced anxiety during a meal challenge

Summary

Introduction

Individuals with anorexia nervosa (AN) often exhibit heightened anxiety well before the onset of food avoidance and weight loss that characterize the disorder [1], and anxious traits are frequent precursors to the morbid diagnostic characteristics of AN [2,3,4]. The fact that no bodily modulation had occurred suggested that this was evidence of abnormal interoceptive prediction error signaling [20, 21] According to this model, psychopathology results from a dysregulated ability to adequately sense what is happening in the body resulting a turbulent reference state (i.e., a “noisy baseline”) [22], attentional bias toward threat [23], increased self-related worry, and dysfunctional learning about bodily states over time [24] [for an overview of current models of interoception’s role in psychopathology see [25]]. We did not examine in the previous study whether these interoceptive prediction errors permeated other levels of body representation, such as interoceptive localization, or experiences of anxiety This is important as higher doses of isoproterenol can elicit panic anxiety [26,27,28], making it difficult to discern whether the physiologically induced arousal leading to subjective feelings of interoception and anxiety can be dissociated from the anxiousness that is part of the AN phenotype

Methods

Results

Conclusion