With the goals of obtaining larger sample sizes than represented in OBIC, increasing worldwide coverage, extending the samples to pediatric OCD, comparing OCD to other disorders, and eventually combining imaging data and genetics, van den Heuvel and Stein proposed adding an ENIGMA‐OCD working group to the ENIGMA consortium in 2013. As of 2019, ENIGMA‐OCD consists of 47 samples from 34 institutes in 15 countries on 5 continents, with a total sample of 4,648 with MRI data of 2,323 OCD patients (1,824 adults (>18 years), 359 adolescents (12–17 years), 140 children (<12 years)) and 2,325 controls (1,724 adults, 325 adolescents, and 166 children; Figure 1).
