A longitudinal event-related potential study of selective serotonin reuptake inhibitor therapy in treatment-naïve pediatric obsessive compulsive disorder patients

Obsessive-compulsive disorder (OCD) is characterized by obsessive thoughts and/or compulsive behaviors, involving specific cognition and/or information processing disorders. Event-related potentials (ERPs) are commonly used as physiological measures of cognitive function. In conscious patients, ERPs are easily and non-invasively measured. Previous ERP studies have revealed differences between OCD patients and control subjects. Whether ERPs reflect the pharmacological effects of OCD treatment, particularly in treatment-naïve pediatric patients, remains unknown. We used the Child's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) to evaluate the symptomatic severity of 12 treatment-naïve pediatric OCD patients. Comparisons were made with 12 age-, sex-, and intelligence-matched controls. The P300 and mismatch negativity (MMN) components were measured during an auditory odd-ball task at baseline in both groups and after the 3-year serotonin reuptake inhibitor (SSRI) treatment in OCD patients. Compared with controls, P300 amplitudes were smaller n the OCD group at Fz, Cz, Pz, C3, and C4. After SSRI treatment, P300 amplitudes increased partly at Fz and C4 in association with symptomatic improvements. We found a significant positive correlation between P300 amplitude in C4 and CY-BOCS scores. Our findings confirm the utility of SSRIs in pediatric OCD, and suggest the utility of ERPs for evaluating pharmacological effects in treatment-naïve pediatric OCD patients.