Clinical Use and Characterictics of Wechsler İntelligence Scale Revised Form in Attention Deficit Hyperactivity Disorder: a Multicenter Study

Objective:

The primary purpose was to show the level of accuracy that WISC-R scores provide when classifying participants into the ADHD and the healthy control groups. The others were: to show the validity of WISC-R or the extent to which WISC-R measures those characteristics that the test is designed to measure; to fi nd out the scores of Wechsler Intelligence Scale Revised (WISC-R) where patients with Attention Defi cit Hyperactivity Disorder (ADHD) show signifi - cantly lower performance; to fi nd out whether WISC-R scores allows for a DEHB profi le.

Method:

The clinical sample consisted of 415 male participants in the age range of 6-12 years. Cases were diagnosed as ADHD patients according to DSM-IV criteria, were unmedicated fi rst referrals and did not have uncorrected visual or auditory impairments. Their Intelligence Quotient (IQ: 80-129) was in the normal range. The control group consisted of 259 male participants without ant psychiatric diagnoses. The group was similar to the clinical group with respect to the inclusion and exclusion criteria. Intelligence was measured using WISC-R and Raven Standard Progressive Matrices (RSPM).

Results:

The effect of group (ADHD, healthy control group) on the WISC-R and RSPM scores were examined using Multivariate Analysis of Covariance (MANCOVA), where age served as the covariate. Group had signifi cant effects on WISC-R and RSPM scores. Consistent with the structure of WISC-R, Principal Component Analysis obtained from the WISC-R scores of the control group revealed three separate factors, corresponding to verbal IQ, performance IQ and attention. The factor structure obtained by the ADHD group was not as organized. The predictability of group membership from the subtest scores of WISC-R was examined by performing Logistic Regression Analysis. Results showed that while the accuracy of prediction in classifying the ADHD patients was 84.80%, it was 45.60% in classifying the healthy participants. When RSPM scores were included in the analyses, the accuracy of the prediction increased to 68.20 % in the control group whereas there was no change in the accuracy rate for the ADHD group.

Discussion:

Results obtained from the present study revealed that WISC-R scores do not suffi ciently distinguish between the ADHD patients. Future studies will show whether the newer version of WISC-R (WISC-IV) has a stronger discriminative value. As it is, authors recommend the utilization of standardized neuropsychological tests along with WISC-R in the diagnostic procedures pertaining to ADHD.