An Examination of the Effects of Stimulant Medication on the IQ Test Performance of Children with AD/HD

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Jennifer S. Adams (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Arthur Anastopoulos

Abstract: In general it is thought that children with AD/HD have lower IQs than nonaffected children. However, the variability in research findings has made it difficult to reach an accurate conclusion regarding the intellectual functioning of children with AD/HD. A primary reason for such inconsistencies appears to be the failure to assess the effects of stimulant medication on test performance. The current study investigated whether changes occur in the WISC-IV test scores of children with AD/HD as a function of stimulant medication usage. Thirty-five male and female children who were diagnosed with AD/HD and taking stimulant medication to treat their symptoms participated in the study. A within-subjects design was used whereby all children were tested on two occasions with a split-half version of the WISC-IV. Children were randomly assigned to be on medication for one testing session and off medication for the other session. As expected, medication usage improved scores on the FSIQ, with an average increase of seven points. This increase in scores appeared to be driven by improved performance on several indices including the Working Memory Index (WMI), Processing Speed Index (PSI), and Verbal Comprehension Index (VCI), with the largest increase seen on the WMI. Children identified as having a positive response to their medication showed the largest improvements on IQ scores. This study provides evidence that children with AD/HD do not necessarily have lower IQs than unaffected children. Implications for the assessment and treatment of children with AD/HD were discussed.

Additional Information

Language: English
Date: 2008
Stimulant Medication, IQ, ADHD, WISC-IV test, children
Attention-deficit-disordered children $x Education $x Research.
Attention-deficit hyperactivity disorder $x Chemotherapy $x Research.
Wechsler Intelligence Scale for Children $x Evaluation.
Intelligence tests.

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