routinely excluded based on parental diagnoses of ADHD or subclinical obsessive-compulsive symptoms (OCB), or if only one parent had TS, CMVT, or OCD. Parents and all siblings thought to have a tic disorder were assessed for TS and related tic disorders, OCD, OCB, and ADHD. Siblings thought to be unaffected were not routinely recruited into the study, although siblings who were recruited into the study and later were determined not to have TS (N=14) were included. Eighty-six percent of probands and siblings were age 18 or under: their mean age was 14 years (SD=5.6 years). The mean age of the parents was 43 years (SD=5.7 years). Of the 589 individuals with TS (including parents and offspring), 203 (34.5%) were over age 18. Adults with TS were more likely to be female (44% vs. 25%, X2=22.6, p<0.0001). There were no significant differences between adults and children with TS in the rates of OCD or ADHD. The study was approved by the Institutional Review Boards of the respective institutions and written informed consent was obtained. Assent was obtained for subjects younger than 13 years.
