The ENIGMA-OCD working group includes 46 data sets from 36 international research institutes, with neuroimaging and clinical data from adult (≥18 years) and pediatric (<18 years) samples. In total, we analyzed data from 4372 participants, including 2304 OCD patients (n = 1801 adult, n = 503 child) and 2068 healthy controls (HC; i.e., free of psychopathology; n = 1629 adult, n = 439 child), with 38 of 46 datasets identical to those described in previous mega-analyses by this working group6,7,22. All participating sites obtained permission from their local institutional review boards or ethics committees to provide anonymized data for analysis, and all study participants provided written informed consent. Demographic and clinical characteristics of each site are detailed in supplementary Table S1. A complete overview of instruments used to obtain diagnosis and clinical information can be found elsewhere (Data Supplement 1, Supplementary Section S1)7. Diagnosis was determined in accordance with DSM2; MINI and SCID were used for adult samples and K-SADS, MINI-KIDS and ADIS were used for pediatric samples23–27.
