Multimodal Neurophysiological Responses to Body Image Stimuli in Men with Muscle Dysmorphia and Steroid Use

Abstract

Muscle dysmorphia (MD), a subtype of body dysmorphic disorder (BDD), involves a pathological preoccupation with muscularity and is commonly linked to anabolic steroid and performance-enhancing drugs (PEDs) use. Despite its rising prevalence, the neurophysiological and affective mechanisms underlying MD, particularly in steroid users, remain underexplored. This study examined 71 male strength-training participants (35 with BDD/ steroid use; 36 controls) during a passive viewing task of muscular, average, and slender male physiques while recording electroencephalography (EEG), electrodermal activity (EDA), and eye-tracking data. Psychometric assessments captured muscularity concerns (Muscle Dysmorphic Disorder Inventory, MDDI), anxiety (State-Trait Anxiety Inventory, STAI), obsessive-compulsive symptoms (Obsessive-Compulsive Inventory-Revised, OCI-R), appearance-related anxiety (Social Appearance Anxiety Scale, SAAS; Social Physique Anxiety Scale, SPAS), and selfesteem (Self-Liking/Self-Competence Scale-Revised, SLCS-R). The BDD/MD group showed significantly heightened responses to muscular stimuli across all modalities. EEG results revealed increased P300 and late positive potential (LPP) amplitudes, along with greater left-lateralized frontal alpha asymmetry. Eye-tracking indicated longer fixation durations and more frequent fixations on muscular images. EDA results showed elevated levels of autonomic arousal. Between-group differences in psychometric measures were substantial, with large effect sizes. Correlational analyses demonstrated significant associations between MD severity and neurophysiological markers, including LPP amplitude, frontal asymmetry, and EDA reactivity. These findings suggest that men with MD and steroid/PEDs use exhibit amplified attentional, emotional, and physiological reactivity to muscular body images. The integration of EEG, EDA, and eye-tracking provides novel insights into the neurocognitive-affective profile of BDD/MD, emphasizing the salience of idealized physiques in this population. Results support the potential utility of multimodal measures as objective indicators for assessing body image disturbance and underscore the need for targeted interventions addressing perceptual and emotional dysregulation in BDD/MD.