Enhanced action tendencies in high versus low obsessive-compulsive symptoms: an event-related potential study

Obsessive-compulsive disorder (OCD) is an anxiety disorder characterized by repeated thoughts and behaviors. Inhibitory deficits are presumably related to the onset and maintenance of this disorder. The present study investigated whether obsessive-compulsive (OC) symptoms are related to enhanced response tendencies in reaction to external stimuli. Our goal was to search for direct evidence of an early response preparation process by examining the event-related potential (ERP) component of the readiness potential (RP). An enhanced response tendency might underlie inhibitory deficits in OCD. Response to novel stimuli was studied using a dishabituation paradigm in which a small number of schematic faces (angry or neutral) were presented. An analog sample of healthy subjects was divided into groups of high and low OC levels and high and low trait anxiety levels. The high OC group presented with a greater RP slope gradient that was enhanced under negative valence, compared to the low OC group. No such effect was found in the high versus low trait anxiety groups or in behavioral reaction times (ms). Results support the hypothesis that a stronger readiness for action might characterize subjects with OC symptoms, especially in the presence of threatening stimuli. This finding, specific to OC symptoms and not to anxiety symptoms, may underlie habitual and embodiment tendencies in OCD. This study suggests that early stages of motor preparation might be important to the etiology and maintenance of OC symptoms.