• OCD;
  • anxiety disorder;
  • P3 amplitude;
  • electroencephalography;
  • orienting response


Background: Cognitive models propose that anxiety disorders are associated with an attentional bias toward potentially threatening stimuli. In this study, it was analyzed whether patients with obsessive–compulsive disorder (OCD) show enhanced responses of their event-related brain potentials to novel stimuli, either in a context of potential threat or in a neutral context. Methods: In this study, 20 OCD patients and 20 matched healthy control subjects performed a visual recognition task during which irrelevant repeated standard sounds and unitary novel sounds were interspersed. Results: As expected, OCD patients showed an increase in the novelty-P3 amplitude elicited by unitary novel sounds. However, no effect of emotional context conditions was observed. Conclusion: It is suggested that the novelty P3 amplitude increase in OCD patients represents a physiological indicator of an enhanced cortical orienting response implicating stronger involuntary shifts of attention. This characteristic is driven by novelty per se and not moderated by potential threat of upcoming events. Depression and Anxiety, 2011. © 2011 Wiley-Liss, Inc.