Response-inhibition deficits in obsessive-compulsive disorder: an indicator of dysfunction in frontostriatal circuits.

Abnormalities in the orbital prefrontal cortex and its ventral striatal target fields are believed to be involved in causing obsessive and compulsive symptoms. Lesions to this brain circuitry result in a selective disturbance in suppressing responses to irrelevant stimuli. This disturbance might underlie the apparent inhibitory deficit suggested by the symptomatology of obsessive-compulsive disorder (OCD). Oculomotor tests were administered to 12 medication-free, nondepressed patients with OCD aged 18 to 44 y and 12 matched healthy controls to assess the ability to suppress responses and to execute delayed responses volitionally. Patients with OCD had more response-suppression failures than controls when peripheral visual targets were presented close to central fixation. No significant case-control differences were observed on the delayed-response task. A basic disturbance of neurobehavioral inhibition in OCD may underlie the repetitive behavior that characterizes the illness and be related to abnormalities in orbital prefrontal ventral striatal circuits.