The TS sample consisted of 1286 individuals recruited from 20 sites in the US, Canada, UK, Netherlands, and Israel, and included subjects of general European (EU) ancestry as well as two EU-derived population isolates of Ashkenazi Jewish (AJ) and French Canadian (FC) descent. Co-occurring OCD symptoms were assessed in 77% of participants; 46% of those evaluated had co-occurring OCD (N=452). OCD status was unknown for 300 individuals with TS.
