The case for DSM-IV subtypes in ADHD

This article selectively reviews research that has examined the three DSM-I V attention deficit-hyperactivity disorder (ADHD) subtypes. Data relevant t o the validity of the subtyping system, including demographic, comorbidity, cognitive/attentional, and social correlates of the three subtypes are pre sented. The majority of relevant research has examined the ADHD/C and ADHD/ IA subtypes, with less information available for the newly identified ADHD/ HI subtype. Findings support the existence of the ADHD/IA subtype; children so diagnosed show impairment and patterns of dysfunction unique from those with the ADHD/C subtype. Further research on many aspects of ADHD/IA is ne eded to clarify whether it is best considered a separate disorder or an ADH D subtype, however, and to determine the most appropriate diagnostic criter ia. Although the scant existing data also suggest that the ADHD/HI subtype is associated with impairment and a different pattern of deficits relative to the other two subtypes, further elucidation of its developmental course is needed to clearly determine its validity, (C) 1999 Wiley-Liss. Inc.