2025

Wang, Jinxia

Obsessive-Compulsive Disorder (OCD) is characterized by persistent obsessions and compulsions driven by anxiety. It is traditionally studied through fear conditioning, which explains how acquired anxiety fails to diminish over time. Recent research suggests that disgust, rather than fear, plays a key role in OCD. Therefore, instead of fear, this dissertation investigates disgust conditioning across three levels of cognitive processing relevant to pathogenesis of OCD: perceptual, conceptual, and imagery-based conditioning. Perceptual-level conditioning links sensory stimuli with potentially threatening outcomes, representing the most automatic form of disgust learning. Conceptual-level conditioning extends to associations between more abstract categories and threat outcomes, requiring higher cognitive processes. In addition, disgust learning can also occur through mental visualization of scenarios linking stimuli and responses. In Studies I and II, participants with high and low sub-clinical OCD levels were grouped based on contamination concerns: the high contamination concerns (HCC) group and the low contamination concerns (LCC) group. In Study I (perceptual level conditioning), the results showed the HCC group exhibited enhanced disgust acquisition. Event-related potential results revealed smaller P3 amplitudes, indicating excessive avoidance during conditioning. In Study II, the results showed that the HCC participants displayed persistently higher US expectancy ratings to the CS+ during acquisition and early extinction, indicating enhanced disgust acquisition and reduced extinction during conceptual-level conditioning. Study III demonstrated that disgust imagery alone could elicit significant conditioned disgust responses, with enhanced P3 and late positive potential (LPP) amplitudes. In all studies, disgust showed resistance to extinction. These findings suggest that heightened disgust acquisition at perceptual and conceptual levels in individuals with high contamination concerns may contribute to the onset of OCD. Importantly, OCD could even developed without actual experiences. This dissertation offers insights into OCD symptom maintenance and could help optimize treatments.