Long-Term Effects of Cognitive Behavioral Therapy on Planning and Prefrontal Cortex Function in Pediatric Obsessive-Compulsive Disorder

Background: Previous studies showed changes after cognitive behavioral therapy (CBT) in prefrontal cortex function and cognitive performance in pediatric obsessive-compulsive disorder (OCD). It remains unknown whether these changes are short lasting or persistent during a period of brain maturation. Here, we investigated the long-term effects of CBT on planning performance and brain function in pediatric OCD using a longitudinal design. Methods: Fifteen pediatric OCD patients and 16 matched healthy control subjects ranging from the ages of 8 to 18 years performed the Tower of London planning task during functional magnetic resonance imaging at three time points: before treatment, after 16 sessions of CBT, and after 2 years of naturalistic follow-up. Results: Group × time interaction analyses showed differential changes from baseline to long-term follow-up in planning performance and brain activity between patients and control subjects. At baseline, patients were slower but as accurate on the planning task and recruited the left inferior frontal gyrus, middle frontal gyrus, and anterior insula more often than control subjects did. These differences were no longer present after CBT and after 2 years of follow-up. Conclusions: Pediatric OCD patients, compared with healthy control subjects, showed longer reaction times and additional recruitment of frontal brain regions during planning. These differences tended to normalize after CBT, and the process continued during 2 years of follow-up. This longitudinal study shows long-lasting changes in cognitive performance and prefrontal cortex function after CBT and suggests that planning dysfunction in pediatric OCD is a state rather than a trait characteristic of the disorder.