title: The validity of the DSM-IV subtypes of attention-deficit/hyperactivity disorder.
abstract: OBJECTIVE
  To examine the validity of the three subtypes of ADHD defined by DSM-IV.
  
  
  METHODS
  Studies published in English were identified through searches of literature databases.
  
  
  RESULTS
  Estimates of the prevalence of ADHD have increased as a result of the introduction of DSM-IV criteria. Factor analytical and genetic studies provide some support for the validity of the distinction between the three subtypes. However, diagnosis of the combined subtype seems more reliable than the other two subtypes, although reliability is largely unknown for the latter. The hyperactive-impulsive subtype, the least common, differs from the other two subtypes in age distribution, association with other factors and neuropsychological parameters. Almost all treatment trials are based on participants with the combined type.
  
  
  CONCLUSIONS
  Data supporting the validity of the inattentive and hyperactive-impulsive subtypes of ADHD a decade after the publication of DSM-IV are still scarce. Given that inattention is the hypothesized core ADHD symptom, it remains to be demonstrated that hyperactive-impulsive children who are not inattentive have the same condition. One of the main research deficits refers to data on treatment of the inattentive and hyperactive-impulsive subtypes.
authors.affiliation: Child Guidance Clinic, 3, Second Hospital Avenue, #03-01, Health Promotion Board Building, Singapore 168937, Singapore. bernardine_woo@imh.com.sg
authors.forename: Bernardine S C
authors.initials: BS
authors.lastname: Woo
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Rey
mesh_terms: D000124:Achievement; D000293:Adolescent; D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004777:Environment; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D011584:Psychology; D015203:Reproducibility of Results