Several studies using a symptom dimensional approach suggest that symptom dimensions may be mediated by partially distinct neural systems (44; 45). Except for the association between a higher surface area of the left cuneus and ordering/symmetry dimension in children, we did not detect thickness or surface area effects of the other symptom dimensions in children and adults. An explanation may be that symptom subtype differences are more focal and remain undetected in this atlas-based analysis. On the other hand, variance in use of instruments across the participating sites might have led to suboptimal harmonization of the symptom dimension scores and therefore might explain the absence of associations with the symptom dimensions in our study. During harmonization, we defined symptom dimensions in a binary manner as absent or present for each participant based on the (C)Y-BOCS symptom checklist, whereas prior studies have correlated the dimension scores with cortical measures.
