Objective: Attention-deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD) are the 2 most frequent psychiatric disorders co-occurring with Tourette syndrome (TS). Both usually cause greater impairment in psychosocial functioning than the tics themselves. In a previous study, we examined the relationship of attention-deficit/hyperactivity disorder to other comorbid conditions in TS. The relationship of OCD to other comorbidities in TS still remains unclear and is the focus of the present study.
Methods: Pearson's χ tests and logistic regressions (year-wise) were used to examine a cross-sectional sample of children and adolescents (n = 5060) diagnosed with TS, taken from the Tourette Syndrome International Database Consortium. We explored the relationship of OCD to other comorbid conditions in TS across different age groups.
Results: In children (ages 5-10 y) with TS, higher rates of comorbidities were found in the presence compared with the absence of OCD. Adolescents (ages 11-17 y) with TS + OCD showed higher rates of internalizing (i.e., anxiety and mood) disorders when compared with those with TS - OCD. A year-wise increase of coexisting mood disorders was found for subjects with TS with and without OCD.
Conclusions: Overall, children and adolescents with TS + OCD showed higher rates of comorbid disorders compared with those with TS - OCD. This underlines the necessity for a comprehensive assessment of additional comorbidities even if the 2 disorders (TS + OCD) have already been diagnosed.