A developmental index using the Wechsler Intelligence Scale for Children: implications for the diagnosis and nature of ADHD.

The possible utility of Wechsler's Deterioration Index (WDI) in analyzing children's Wechsler Intelligence Scale for Children-Revised (WISC-R) results was explored in this study. Clinical records of children with learning disabilities (LD) and children with attention deficit-hyperactivity disorder (ADHD) were reviewed to determine if the WDI predicted the presence or severity of the disorders. The ages of the children ranged from 6 to 14. In two independent samples of children with LD (n = 35 and n = 26), the WDI did not predict LD status or severity. The LD samples were mostly male--85% and 57%, respectively. However, the WDI scores did significantly distinguish children with ADHD (n = 10) from nondisabled children (n = 10). The results were cross-validated on an independent sample of children with ADHD (n = 17) when compared to non-ADHD children (n = 22) who experienced significant behavioral difficulties. The ADHD samples were also mostly male--90% and 89%, respectively. The WDI classified only 59% of the children with ADHD and 86% of the non-ADHD children correctly. It is recommended that the WDI be considered a developmental index rather than a deterioration index in children. It is also recommended that significant WDI elevation (greater than .20) be considered to raise the question of ADHD, rather than simply yielding a diagnosis of ADHD.