Towards defining a meaningful anxiety phenotype for research in ADHD children

Abstract
Objective: To combine anxiety diagnoses empirically into a meaningful definition of a comorbid anxiety syndrome in ADHD children. Methods: The prevalence of all DSM-111-R anxiety disorders was examined in our ADHD sample (N =237) and a Receiver Operating Characteristic (ROC) analysis was conducted to combine the information optimally from these many disorders into a single anxiety phenotype. Results: We found that two or more anxiety disorders correctly identified a large number of ADHD children as anxious (SN=0.75) while maintaining a reasonable false positive rate (Sp=0.67). In contrast, the criterion of three or more anxiety disorders correctly identified only half the sample and the criterion of one or more anxiety disorders had a much higher false positive rate. The necessary data are also presented for those that may wish to use a definition other than 2 or more anxiety disorders. Conclusion: These findings suggest that using 2 or more anxiety disorders may offer a useful approach to defining comorbid anxiety in ADHD youth.