Distinguishing illness severity from tic severity in children and adolescents with Tourette's disorder

To examine whether tic severity, comorbid disorders, or both are associated with illness morbidity in youths with Tourette's disorder (TD).

Subjects were 156 consecutively referred youths (aged 5-20 years) who met DSM-III-R criteria for Tourette's disorder at a major academic medical center. All subjects were evaluated with a clinical interview by a child and adolescent psychiatrist and an assessment battery that included the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Epidemiologic version. Statistical analysis used chi 2 and multivariate logistic regression.

Nineteen (12%) of the 156 youths with TD required psychiatric hospitalization. Current age, TD severity, TD duration, obsessive-compulsive disorder, psychosis, major depression, bipolar disorder, panic disorder, and overanxious disorder were significant univariate predictors of psychiatric hospitalization (p < .01). While tic severity was marginally significant as a predictor of psychiatric hospitalization (p < .05), major depression (p < .016) and bipolar disorder (p < .001) were robust predictors of psychiatric hospitalization, even after statistical adjustment for collinearity and correction for all other variables assessed.

The findings indicate that comorbid mood disorders are strongly associated with illness morbidity in youths with TD, highlighting the importance of attention to comorbidity in patients with TD.