Anxiety disorders and tic severity in juveniles with Tourette's disorder.

OBJECTIVE: It was hypothesized that comorbidity with anxiety disorders would predict tic severity in youths with Tourette's disorder (TD).
METHOD: Subjects were 190 youths meeting DSM-III-R diagnostic criteria for TD who were consecutively referred to a pediatric psychopharmacology program between 1994 and 1997. Subjects were initially evaluated with a clinical interview and the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Epidemiologic version. Statistical analysis used t tests, chi 2 tests, and logistic regression analysis.
RESULTS: One hundred thirty-four subjects were classified as mild/moderate and 56 as severe TD cases. No meaningful differences were found in socioeconomic status, gender distribution, or age at onset of TD between the 2 groups. The 2 groups could not be differentiated by the presence of comorbid mood or disruptive behavior disorders including attention-deficit hyperactivity disorder. Although obsessive-compulsive disorder (OCD) was overrepresented among the severe TD cases, the difference failed to reach statistical significance. Excluding social and simple phobias, all other anxiety disorders were more clearly overrepresented among subjects with severe TD; separation anxiety disorder most robustly predicted tic severity, irrespective of the presence of OCD or other anxiety disorders.
CONCLUSION: Findings suggest that non-OCD anxiety disorders in general and separation anxiety disorder in particular may be significantly associated with tic severity in referred TD patients.