Comorbidity in Pediatric OCD

Tic disorders, including Tourette syndrome (TS), are not formally part of the category of “OCD-related disorders” in the DSM; but the association with OCD is sufficiently strong, and clinically important, that the OCD diagnosis now carries an optional “tic-related” specifier. Comorbidity is the norm in TS; in addition to OCD, attention deficit symptoms are particularly common. The presence of these comorbidities can affect both behavioral and pharmacological treatments, which are reviewed in this chapter. Tics commonly begin in childhood (part of the definition of TS), often improving in late adolescence. Approximately 30% of children with TS will develop OCD; the onset of OCD symptoms is usually later than that of tics, and they are more likely to persist into adulthood. Tic-associated OCD has a male preponderance and is more likely to be characterized by symmetry-related obsessions and compulsions. Like OCD, tic disorders are characterized by abnormalities in the cortico-striatal circuitry.