background Neuroimaging studies of children and adolescents with obsessive compulsive disorder (OCD) reveal abnormalities in fronto-striatal circuits. However, little is known how cognitive behavioral therapy (CBT) changes this neurobiological basis of obsessive compulsive behavior.
aim To find out which neurocircuits change after CBT in pediatric OCD.
method Twenty-nine medication-free children and adolescents with OCD (age range 9-19, mean 13.8) were scanned in a mri-scanner before and after 16 sessions of CBT. Twenty-nine age- and gender-matched healthy controls were scanned in the same manner. Structural and functional scans were made. During the functional scans a planning paradigm (Tower of London), an error monitoring task (Flanker task) and a task for selective attention (dot-probe task) were executed.
results Patients show on a structural level regional gray and white matter volume differences with healthy controls before treatment, especially an increase of gray matter volume in the frontal pole and insula. After treatment ocd patients show an increase of regional grey matter volume in the orbitofrontal cortex. White matter volume shows an increase in bilateral capsula externa. Functional imaging during planning revealed an hypoactivation of dorsolateral and parietal structures before treatment. After treatment this difference ceased to be significant. Error monitoring showed only in elderly patients more activation of the rostral anterior cingulate cortex which did not change after cbt. The selective attention task showed more hippocampal activation before treatment which normalized after treatment.
conclusion CBT for children and adolescents with OCD changes the volume and function of certain brain regions especially in dorsal and ventral fronto-striatal circuits.