posterior thalamic radiation (Cohen's d = −0.26). Lower FA in the sagittal stratum was associated with a younger age of onset (z = 2.71), longer duration of illness (z = −2.09), and a higher percentage of medicated patients in the cohorts studied (z = −1.98). No significant association with symptom severity was detected. Pediatric OCD patients did not show any detectable microstructural abnormalities compared to matched healthy controls. These results suggest that in adult OCD patients the reported microstructural alterations in projection and association fibers to posterior brain regions are partly related to disease course and medication status, and thus are likely more a consequence than a cause of disease.
