Differences between preschool children with ODD, ADHD, and ODD plus ADHD symptoms

Background: This study examines differences between children (ages 3 to 6 years) who have the symptoms of oppositional defiant disorder (ODD) with or without attention-deficit/hyperactivity disorder (ADHD), ADHD alone, and a nonODD/ADHD comparison group. Parent (N = 595) and teacher (N = 538) ratings were obtained for children attending the same community early childhood programs and for youngsters evaluated in an outpatient clinic (N = 224) using a DSM-IV-referenced rating scale. Results: Differences between symptom groups varied depending on how they were configured (teacher versus parent ratings) and setting (clinic versus community). In general, the ODD+ADHD group received the highest (and the comparison group the lowest) ratings of severity for the symptoms of other disorders, difficulties with peers, and developmental deficits. Moreover, the clinical impact of comorbidity was largely additive. Differences between youngsters with ODD versus ADHD symptoms were most apparent for teacher-defined groups in the community sample and parent-defined groups in the clinic sample. Conclusions: Collectively, these findings provide preliminary evidence for the notion that ODD and ADHD may constitute distinct clinical entities in preschool-aged children and suggest that informant may be an important consideration in the formulation of diagnostic criteria.