title: Differences between preschool children with ODD, ADHD, and ODD+ADHD symptoms.
abstract: 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.
authors.affiliation: Department of Psychiatry, State University of New York, Stony Brook 11794-8790, USA. kgadow@mail.psychiatry.sunysb.edu
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Gadow
authors.forename: Edith E
authors.initials: EE
authors.lastname: Nolan
mesh_terms: D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000523:psychology; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000175:diagnosis* / Q000523:psychology; D002675:Child, Preschool; D015897:Comorbidity; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D010552:Personality Assessment; D011569:Psychiatric Status Rating Scales