Interoceptive Anxiety and Body Representation in Anorexia Nervosa

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.

Interoception in Anorexia Nervosa: Exploring Associations With Alexithymia and Autistic Traits

“…Significantly, these studies similarly found no difference in interoceptive accuracy, but did find prediction errors made specifically in the context of meal anticipation. This appeared to be related to heightened anxiety, and atypical interoceptive representation of the heartbeat: individuals with AN located sensations in the left side of their chest in the absence of actual stimulation (56). Further research should consider exploring aspects of interoception in AN other than accuracy, including the ability to discriminate between sensations, or magnitude estimations.…”

“…If individuals with AN have less confidence in their ability to detect interoceptive sensations, this could result in a reliance on other cues, such as prior beliefs around likely interoceptive responses. The possibility that people with AN rely on predicted sensations, as opposed to the detection of actual sensations, is supported by research suggesting that people with AN find it difficult to detect actual interoceptive responses from anticipated responses (55,56). Individuals with AN were more likely to falsely endorse changes in interoceptive sensation in the absence of stimulation, and reported more intense cardiorespiratory sensations compared to HC, during pre-meal states.…”

“…Alternatively, studies on interoception in AN could move away entirely from the heartbeat tracking task to a more robust measure of interoceptive accuracy. For example, recent studies on cardiac interoception in AN have instead used bolus intravenous infusions of isoproterenol to artificially raise heartbeat and respiratory rate in a controlled manner, and then asked participants to rate their changing sensations using a dial (55,56). While this type of methodology is more invasive compared to the heartbeat tracking task, it does allow for a more highly controlled approach.…”

On bells, saliva, and abdominal pain or discomfort: Early aversive visceral conditioning and vulnerability for anorexia nervosa

“…While the term interoception is now employed more precisely to distinguish the various phases at which an individual can sense, interpret, and integrate visceral sensations into adaptive actions (Khalsa et al, ), this earlier conceptualization of low interoception has been documented as a nonspecific, variable risk factor of low to medium effect (Jacobi et al, ). More recently, controlled laboratory studies verified that in ambiguous conditions, individuals with AN have difficulty discriminating adaptive visceral signals from false alarms and experience “visceral illusions” that indicate decreased body awareness (Khalsa et al, ; Khalsa et al, ). Thus our conceptualization adds to this body of evidence by highlighting the potential importance of early GI events as contributing to subsequent somatic avoidance and confusion.Hypothesis Early GI events may increase vulnerability to the development of a fear of weight gain specifically and dangerous weight‐loss behaviors that have the added motivation of altering GI experience.…”

Feeling the beat: Temporal and spatial perception of heartbeat sensations

“…During low arousal states, participants mostly felt their heartbeats in the lower left chest. Some participants also reported heartbeat sensations in the head, neck, belly and arms (Hassanpour et al 2016;Khalsa et al 2018;. Good heartbeat perceivers, based on how accurately they performed the heartbeat detection 'counting' task (in which the reported number of 'felt' heartbeats, counted over different time periods are compared to veridical heartbeats, measured using ECG) report more spontaneous sensations (SPS; e.g.…”