regional differences in subcortical structures can be inferred from atlas‐based FreeSurfer analyses. Using exactly the same OBIC sample as was used in the VBM mega‐analysis (De Wit et al., 2014), Fouche et al. (2017) used vertex‐wise FreeSurfer to compare cortical thickness and subcortical volumes in patients versus controls, and showed that adult OCD patients have a thinner cortex in a number of frontal, temporal, and parietal regions and smaller bilateral hippocampus. These findings partly overlap with the VBM‐based results, but also show that results and their interpretation depend to some extent on the methods used.
