ADHD Combined Type and ADHD Predominantly Inattentive Type Are Distinct and Unrelated Disorders
Article first published online: 11 MAY 2006
Clinical Psychology: Science and Practice
Volume 8, Issue 4, pages 463–488, December 2001
How to Cite
Milich, R., Balentine, A. C. and Lynam, D. R. (2001), ADHD Combined Type and ADHD Predominantly Inattentive Type Are Distinct and Unrelated Disorders. Clinical Psychology: Science and Practice, 8: 463–488. doi: 10.1093/clipsy.8.4.463
- Issue published online: 11 MAY 2006
- Article first published online: 11 MAY 2006
- Received May 31, 2000; revised September 11, 2000; accepted September 14, 2000.
- attention defict hyperactivity disorder;
- ADHD combined;
- ADHD inattentive;
- ADHD subtypes;
- ADHD classification
We comprehensively reviewed research assessing differences in attention-deficit hyperactivity disorder (ADHD) subtypes to examine the possibility that ADHD/ combined type (ADHD/Q and ADHD/predominantly inattentive type (ADHD/I) are distinct and unrelated disorders. Differences among subtypes were examined along dimensions identified as being important in documenting the distinctiveness of two disorders. These include essential and associated features, demographics, measures of cognitive and neuropsychological functioning, family history, treatment response, and prognosis. Important differences among subtypes were found in several areas of study, supporting the conclusion that ADHD/C and ADHD/I may best be characterized as distinct disorders. We identify major limitations of the available research and present future directions for research.