Re-examining comorbidity of Obsessive Compulsive and Attention-Deficit Hyperactivity Disorder using an empirically derived taxonomy

Background: Using an empirically derived instrument to reduce the assessor bias inherent in structured diagnostic interviews, we sought to re-examine and validate the putative comorbidity between Obsessive Compulsive Disorder (OCD) and Attention-Deficit/Hyperactivity Disorder (ADHD) in children and adolescents. Method: We examined the correlation between Child Behavior Checklist (CBCL) syndrome, competence, and composite scores in children with: 1) OCD plus ADHD (OCD + ADHD), N = 47; 2) OCD without comorbid ADHD (OCD), N = 33; 3) ADHD without comorbid OCD (ADHD) N = 43; and 4) comparison controls recruited from general pediatric clinics, N = 32. Results: CBCL findings in our ADHD children were similar to previous findings reported in ADHD youth, irrespective of the presence or absence of comorbid OCD. Comorbid youth generally had additive scores on the CBCL scales, reflecting the independent contribution of symptomatic and functional impairment from each disorder. Conclusion: These findings suggest that when ADHD-like symptoms are seen in OCD youth, they reflect a true comorbid state of OCD plus ADHD. The CBCL may provide a rapid assessment tool to identify comorbid ADHD in OCD youth.