Enhanced error related negativity amplitude in medication-naïve, comorbidity-free obsessive compulsive disorder.

Error monitoring and response inhibition is a key cognitive deficit in obsessive-compulsive disorder (OCD). Frontal midline regions such as the cingulate cortex and pre-supplementary motor area are considered critical brain substrates of this deficit. Electrophysiological equivalent of the above dysfunction is a fronto-central event related potential (ERP) which occurs after an error called the error related negativity (ERN). In this study, we sought to compare the ERN parameters between medication-naïve, comorbidity-free subjects with OCD and healthy controls (HC). Age, sex and handedness matched subjects with medication-naïve, comorbidity-free OCD (N = 16) and Healthy Controls (N = 17) performed a modified version of the flanker task while EEG was acquired for ERN. EEG signals were recorded from the electrodes FCz and Cz. Clinical severity of OCD was assessed using the Yale Brown Obsessive Compulsive Scale. The subjects with OCD had significantly greater ERN amplitude at Cz and FCz. There were no significant correlations between ERN measures and illness severity measures. Overactive performance monitoring as evidenced by enhanced ERN amplitude could be considered as a biomarker for OCD.