Gender* | χ^{2} = 0.778; p = 0.780 | Fisher; p = 1.00 |

Age at interview (under or over 18)* | χ^{2} = 3.73; p = 0.053 | Fisher; p = 0.205 |

Referral source | χ^{2} = 17.2; p = 0.002 | Fisher; p = 0.571 |

Tic severity | | |

Motor | Z = 5.45; p<0.0001 | Z = 2.14; p = 0.032 |

Phonic | Z = 4.93 p<0.0001 | Z = 2.63; p = 0.009 |

Environmental and genetic factors | | |

Prenatal problems* | χ^{2} = 0.41; p = 0.82 | Fisher; p = 0.396 |

Perinatal distress* | χ^{2} = 1.43; p = 0.49 | Fisher; p = 0.75 |

Family history of TS* | χ^{2} = 0.28; p = 0.60 | Fisher; p = 0.695 |

Bilineal family history of TS* | χ^{2} = 0.64; p = 0.42 | Fisher; p = 0.282 |

Family history of OCS | χ^{2} = 14.07; p<0.0001 | Fisher; p = 0.75 |

Obsessive symptoms | | |

OCD | Fisher; p<0.0001 | Fisher; p = 0.008 |

Number of obsessive symptoms | Z = 5.28; p<0.0001 | Z = 2.1; p = 0.03 |

Violent obsessions | χ^{2} = 33.85; p<0.0001 | Fisher; p = 0.028 |

Violent/aggressive compulsive behaviours | χ^{2} = 28.39; p<0.0001 | Fisher; p = 0.005 |

Attentional symptoms | | |

ADHD | χ^{2} = 5.19; p = 0.023 | Fisher; p = 0.121 |

ADHD, impulsive symptoms | Fisher; p = 0.089 | Fisher; p = 0.141 |

ADHD, inattentive symptoms* | χ^{2} = 3.71; p = 0.16 | Fisher; p = 0.163 |

ADHD, hyperactive symptoms* | Fisher; p = 0.033 | Fisher; p = 0.141 |

Other psychiatric comorbidities | | |

OCD+ADHD | χ^{2} = 17.67; p<0.0001 | χ^{2} = 7.89; p = 0.005 |

Rages | χ^{2} = 5.53; p = 0.019 | Fisher; p = 0.002 |

Risk taking | Fisher; p = 0.02 | Fisher; p = 0.122 |

Anxiety disorders* | χ^{2} = 0.48; p = 0.49 | Fisher; p = 1.000 |

Mood disorders* | Fisher; p = 1.000 | Fisher; p = 0.301 |

Conduct disorders* | χ^{2} = 1.23; p = 0.27 | Fisher; p = 0.133 |

Eating disorders* | χ^{2} = 0.027; p = 0.87 | Fisher; p = 0.214 |