Cognitive electroencephalographic potentials evoked by words as markers of the severity of the pathology and resistance to treatment in obsessive-compulsive disorder.

Patients suffering from obsessive-compulsive disorder (OCD) show an attentional bias towards pathology-related words. Electroencephalographic cognitive potentials were used to investigate how patients responded to words related to their obsessions and compulsions. Forty OCD patients with various levels of severity and treatment-resistance were included to assess links between word-evoked potentials and patients' clinical variables, and compared with 40 control participants. The P200 component evoked by both neutral and pathology-related words was greater in patients than in controls, suggesting that patients were more attentive overall. In the N400 time window, pathology-related words evoked less negative potentials than neutral words in OCD patients, suggesting that pathology-related words were particularly familiar to them and permanently pre-activated in their mental lexicon. Finally, correlations were detected between pathology severity and the profile of word-evoked potentials in the N400 time window, and between the patients' treatment resistance and the amplitude of late word-evoked positive potentials (P600).