CBT Effects on Neurophysiological and Psychological Outcomes in Body Dysmorphic Disorder

This clinical trial aims to investigate how a specific type of psychotherapy called Cognitive-Behavioral Therapy (CBT) can help people who experience Body Dysmorphic Disorder (BDD). BDD is a mental health condition where individuals become excessively preoccupied with perceived flaws in their physical appearance-flaws that are often unnoticeable to others. This distress can interfere significantly with their social, emotional, and daily functioning. The purpose of this study is to evaluate whether a 12-week CBT program can reduce symptoms of BDD and bring about measurable changes in brain activity, physiological stress responses, and patterns of visual attention when individuals view their own faces or appearance-related images. The researchers will use brainwave recordings (EEG), skin response sensors (GSR), and eye-tracking technology to assess these changes. In addition, participants will complete a set of questionnaires that measure depression, anxiety, emotion regulation, self-esteem, body image beliefs, and self-compassion. Sixty individuals will take part in the study. Thirty will receive CBT sessions once a week for 12 weeks, while the other thirty will be placed on a waitlist and offered treatment later. The study will compare how symptoms and neurophysiological responses change before and after therapy, and whether these changes differ between those who received immediate treatment and those who did not. The researchers hypothesize that CBT will reduce emotional distress, improve emotion regulation, and shift brain and body responses toward healthier patterns. This study will help identify how and why therapy works for BDD, and whether technologies like EEG and eye-tracking can be used to monitor treatment progress.

Detailed Description Background and Rationale Body Dysmorphic Disorder (BDD) is a chronic and often severely impairing psychiatric disorder characterized by intrusive preoccupations with perceived flaws in one's appearance-flaws that are often imperceptible to others. Individuals with BDD engage in compulsive behaviors such as mirror checking, grooming, or social avoidance, leading to functional impairment and heightened psychological distress. The condition has a high comorbidity with depression and anxiety, and individuals with BDD are at increased risk for suicidality. Cognitive-Behavioral Therapy (CBT) is the most evidence-based intervention for BDD, targeting cognitive distortions, avoidance behaviors, and emotional dysregulation related to body image. However, despite robust clinical outcomes, the underlying neurophysiological mechanisms of CBT's effectiveness remain insufficiently explored. This trial seeks to address that gap by integrating behavioral symptom change with objective neurophysiological and attentional measures. This study investigates whether a structured 12-week CBT program produces measurable improvements in brain function, autonomic nervous system response, and attentional bias among individuals with BDD. By combining EEG, GSR, and eye-tracking methods with validated clinical instruments, the research aims to clarify how therapy modulates both the subjective experience and biological correlates of body image disturbance. Study Design This is a randomized controlled trial with a pre-post design involving two groups: a CBT intervention group and a waitlist control group. Sixty participants aged 18-50 will be recruited. Thirty participants will meet DSM-5 criteria for BDD and will be randomly assigned to either the CBT intervention group (n=15) or the waitlist control group (n=15). An additional healthy control group (n=30) will serve as a normative baseline for neurophysiological comparisons but will not receive any intervention. The intervention consists of twelve 60-minute weekly CBT sessions focused on psychoeducation, cognitive restructuring, exposure and response prevention (ERP), mindfulness-based emotional regulation techniques, and attentional retraining exercises. Experimental Protocol Participants will undergo pre- and post-treatment assessments that include the following: Neurophysiological Assessment: EEG recordings will measure event-related potentials (ERPs) such as N170, P300, Late Positive Potential (LPP), and frontal alpha asymmetry. GSR will capture sympathetic arousal and recovery rates during exposure to appearance-related stimuli. Eye-tracking will measure fixation duration, pupil dilation, and gaze patterns toward self-perceived flaws and control features. Stimuli: Participants will be exposed to images of their own faces (unaltered, neutral, and digitally altered), appearance-related emotional stimuli (e.g., idealized or distorted faces), and non-threatening neutral or positive stimuli. After each stimulus, they will rate their distress on a Visual Analog Scale (VAS) ranging from 0 to 10. Psychometric Assessment: The following validated self-report and clinician-rated scales will be administered at baseline and post-treatment: Yale-Brown Obsessive-Compulsive Scale Modified for Body Dysmorphic Disorder (BDD-YBOCS): Measures the severity of appearance-related obsessions and compulsions. Body Image Disturbance Questionnaire (BIDQ): Assesses subjective dissatisfaction and interference caused by perceived appearance flaws. Emotion Regulation Questionnaire (ERQ): Evaluates cognitive reappraisal and suppression strategies used to manage emotions. Beck Depression Inventory-II (BDI-II): Measures depressive symptom severity. Beck Anxiety Inventory (BAI): Measures general anxiety symptoms. Data Analysis Plan ERP components will be analyzed using repeated-measures ANOVA, focusing on pre-post changes within and between groups. GSR data will be analyzed through paired and independent sample t-tests comparing skin conductance response and recovery. Eye-tracking data will be evaluated using linear mixed-effects models to identify patterns in fixation and gaze shifts. Changes in psychometric scores will be analyzed via paired t-tests and ANCOVAs. Correlation analyses will examine the association between clinical improvement and physiological markers (e.g., reduced BDD-YBOCS scores and normalized alpha asymmetry). The statistical threshold will be set at p \< .05, and all analyses will follow an intention-to-treat approach. Scientific and Clinical Contribution This study represents a novel integration of CBT with multi-modal neurophysiological measurement in the context of BDD. It seeks to identify treatment-sensitive biomarkers of emotional and attentional regulation that may serve both diagnostic and therapeutic purposes. If successful, the findings will contribute to the development of personalized CBT interventions guided by real-time physiological feedback and objective clinical markers.