OBJECTIVE: To clarify whether the symptoms of inattention and distractibility commonly seen in children and adolescents with obsessive-compulsive disorder (OCD) represent true comorbidity with attention-deficit/hyperactivity disorder (ADHD) or a manifestation of obsessional anxiety.

METHOD: Phenotypic features and functional correlates of ADHD-like symptoms were examined in youths with and without OCD from a large sample of pediatric psychiatry patients consecutively referred since 1997.

RESULTS: The number, frequency, and types of core ADHD symptoms as well as ADHD-associated functional indices were identical in all youths with DSM-IV-diagnosed ADHD irrespective of the presence or absence of comorbid OCD.

CONCLUSION: These findings suggest that when ADHD-like symptoms are seen in youths with OCD, they reflect a true comorbid state of OCD plus ADHD and that the ADHD syndrome may be independent of OCD in comorbid youths.