Does comorbid attention-deficit/hyperactivity disorder impact the clinical expression of pediatric obsessive-compulsive disorder?

What is the impact of attention-deficit/hyperactivity disorder (ADHD) on the phenotypic expression of pediatric obsessive-compulsive disorder (OCD). We examined phenotypic features, and functional and clinical correlates in youths with OCD, with and without comorbid ADHD, from a large sample of consecutively referred pediatric psychiatry patients. Although comorbid ADHD had no meaningful impact on the phenotypic expression or clinical correlates of OCD, it was associated with higher rates of compromised educational functioning compared with other OCD youths. Our findings suggest that the OCD phenotype runs true and is not impacted by comorbid ADHD in youths diagnosed with both OCD and ADHD. In such affected youths, both disorders contribute to morbid dysfunction and require treatment. More work is needed to determine whether OCD plus ADHD represents a developmentally and etiologically distinct form of the OCD syndrome.