Signals Crossed: Testing Different Forms of Interoceptive Dysfunction as Facilitators of Muscle Dysmorphia Symptoms

Abstract

Introduction. Interoceptive dysfunction (i.e., difficulties attending to internal sensations) may reflect a risk factor for muscle dysmorphia (MD) symptoms. Specifically, gastric interoceptive dysfunction, elevated pain tolerance, and poor interoceptive sensibility may facilitate MD symptoms. Thus, this study tested various forms of interoceptive dysfunction as risk factors for MD symptoms. Additionally, both self-report and psychophysiological indices of interoception were tested and comparatively evaluated as MD risk factors. Methods. 151 (48.3% men; 90.7% White, Mage = 19.36) university students completed two self-report surveys separated by one month. Participants completed psychophysiological indices of interoception at baseline. Longitudinal regression analyses tested interoceptive variables as predictors of MD symptoms stratified by interoceptive domain (e.g., gastric, pain, general) and sex. Significant predictors were included in a larger model with the full sample to determine the predictive utility of these constructs. Results. Among the subsample of men, self-reported interoceptive sensibility (e.g., viewing body sensations as worrying and increased ability to attend to bodily sensations) predicted MD-functional impairment longitudinally. There were no significant predictors of MD symptoms among the subsample of women. In the larger model using the full sample, increased ability to attend to bodily sensations predicted MD-functional impairment. Discussion. Self-reported interoceptive sensibility predicted MDfunctional impairment; however, no psychophysiological indices of interoceptive dysfunction longitudinally predicted MD symptoms. Although unexpected, increased ability to attend to bodily sensations predicted greater MD-functional impairment (e.g., prioritization of weight training above social/personal responsibilities, anxiety/depression when missing weight training), perhaps by increasing the ‘mind-muscle’ connection and making workouts more reinforcing. As such, clinicians may consider applying clients’ skills in attending to physical sensations to non-exercise related activities to regulate mood (e.g., progressive muscle relaxation) to reduce reliance on weight training sessions.