Objective: To examine the discriminant validity of DSM-IV attention-deficit/hyperactivity disorder (ADHD) subtypes in a nationally representative sample of Australian youths.
Method: The Diagnostic Interview Schedule for Children, including the symptom-specific impairment questions, was administered to 3,597 parents of children aged 6 to 17 years (response rate = 70%). Parents also completed questionnaires assessing children's emotional and behavioral problems and quality of life.
Results: Current DSM-IVADHD prevalence was 7.5% (6.8% with impairment) with inattentive types being more common than hyperactive-impulsive and combined types. ADHD was more prevalent among young males and was linked to social adversity, particularly for combined types. Compared with non-ADHD controls, all three ADHD subtypes were rated as having more emotional and behavioral problems and lower psychosocial quality of life, with combined types consistently rated the most impaired. Combined types received higher ratings than hyperactive-impulsive and inattentive types on externalizing behavior problems, disruption to family activities, and symptom-specific impairments with schoolwork and peer-related activities. Inattentive types were rated as having lower self-esteem, more social and school-related problems, but fewer externalizing problems than hyperactive-impulsive types.
Conclusion: These findings support the view of DSM-IVADHD subtypes as distinct clinical entities with impairments in multiple domains.