Right Prefrontal Cortical Thickness is Associated With Response to Cognitive-Behavioral Therapy in Children With Obsessive-Compulsive Disorder

Objective: Cognitive-behavioral therapy (CBT) is considered a first-line treatment for obsessive-compulsive disorder (OCD) in pediatric and adult populations. Nevertheless, some patients show partial or null response. The identification of predictors of CBT response may improve clinical management of patients with OCD. Here, we aimed to identify structural magnetic resonance imaging (MRI) predictors of CBT response in two large series of adults and children with OCD from the worldwide ENIGMA-OCD consortium. Method: Data from 16 datasets from 13 international sites were included in the study. We assessed which variations in baseline cortical thickness, cortical surface area and subcortical volume predicted response to CBT (percentage of baseline to post-treatment symptom reduction) in two samples totaling 168 children/adolescent patients (age range 5-17.5) and 318 adult patients (age range 18-63) with OCD. Mixed linear models with random intercept were used to account for potential cross-site differences in imaging values. Results: Significant results were exclusively observed in the pediatric sample. Right prefrontal cortex thickness was positively associated with the percentage of CBT response. In a post-hoc analyses, we observed that the specific changes accounting for this relationship were a higher thickness of the frontal pole and the rostral middle frontal gyrus. We observed no significant effects of age, sex, or medication on our findings. Conclusion: Higher cortical thickness in specific right prefrontal cortex regions may be important for CBT response in children with OCD. Our findings suggest that the right prefrontal cortex plays a relevant role in the mechanisms of action of CBT in children. Keywords: anxiety disorders; cognitive-behavioral therapy; magnetic resonance imaging; neuroimaging; obsessive-compulsive disorde