Hanna GL, et al. - Researchers performed error-related negativity (ERN) amplitudes in obsessive-compulsive disorder (OCD) patients with major depressive disorder (MDD) (OCD + MDD), OCD patients without MDD (OCD - MDD), MDD patients, and healthy controls (HC). During a flanker task, they measured the ERN, correct response negativity, and accuracy to assess performance monitoring in 53 adolescents with a lifetime diagnosis of OCD, 36 adolescents with a lifetime diagnosis of MDD, and 89 age-matched HC of 13–18 years. A history of MDD was noted in 14 OCD patients. An enlarged ERN was a neural correlate of adolescent OCD that seemed associated with age at OCD symptom onset. Impaired cognitive control on a flanker task could be observed among adolescents with OCD.