In the present study we had sufficient statistical power to detect subtle (Cohen’s d, −0.15 to −0.31) cortical abnormalities in OCD (Supplemental Information SI5). Large-scale studies such as ours are well powered to distinguish consistent, generalizable findings from false positives. Structural MRI provides a crude and indirect measure of putative alterations at the molecular level, but these subtle abnormalities in the parietal cortex may still be relevant from a pathophysiological perspective (31). These results provide insight into what systems are affected, and promote further research to evaluate specific pathways implicated in the pathophysiology of OCD.
