The initial TS sample consisted of 1,235 individuals recruited from 19 sites in the US, Canada, Europe, and Israel. Participants with DSM-IV-TR-diagnosed TS were recruited primarily from TS specialty clinics or from the Tourette Syndrome Association (TSA). 1,086 (88%) individuals passed sample-level QC. Mean age of tic onset was 6.3 years (SD=3.5). OCD as defined by DSM-IV-TR criteria was assessed in 88% of cases; OCD was present in 46% of assessed TS individuals.
