Validity of DSM-IV ADHD subtypes in a nationally representative sample of Australian children and adolescents

Objective: To examine the discriminant validity of DSM-IV attention-deficit /hyperactivity disorder (ADHD) subtypes in a nationally representative samp le of Australian youths. Method: The Diagnostic Interview Schedule for Chil dren, including the symptom-specific impairment questions, was administered to 3,597 parents of children aged 6 to 17 years (response rate = 70%). Par ents also completed questionnaires assessing children's emotional and behav ioral problems and quality of life. Results: Current DSM-IVADHD prevalence was 7.5% (6.8% with impairment) with inattentive types being more common th an hyperactive-impulsive and combined types. ADHD was more prevalent among young males and was linked to social adversity, particularly for combined t ypes. Compared with non-ADHD controls, all three ADHD subtypes were rated a s having more emotional and behavioral problems and lower psychosocial qual ity of life, with combined types consistently rated the most impaired. Comb ined types received higher ratings than hyperactive-impulsive and inattenti ve types on externalizing behavior problems, disruption to family activitie s, and symptom-specific impairments with schoolwork and peer-related activi ties. Inattentive types were rated as having lower self-esteem, more social and school-related problems, but fewer externalizing problems than hyperac tive-impulsive types. Conclusion: These findings support the view of DSM-IV ADHD subtypes as distinct clinical entities with impairments in multiple do mains.