A Pilot Study of the Usefulness of Intelligence Test in Assessment of Attention-Deficit Hyperactivity Disorder

ABSTRACT

OBJECTIVES: We analyzed the usefulness of intelligence test in assessing attention-deficit hyperactivity disorder (ADHD). METHODS: The medical records of 312 patients with ADHD who visited the child psychiatry department in one university hospital in Seoul, Korea, were reviewed. Demographic data and scores on the Korean Wechsler Intelligence Scale for Children-III (K-WISC-III) and Korean-Conners' Parent Rating Scale (K-CPRS) were analyzed. To assess the relationship with comorbidities, ADHD subjects were classified as; externalizing disorders, internalizing disorders, tic disorders, and no comorbidities. RESULTS: Verbal intelligence quotient (VIQ) was significantly higher than performance IQ (PIQ)(102.6+/-14.44, 99.2+/-14.48, p<.001). Using mean scatter method, subtest scores such as 'information, similarities, digit span and coding' were significantly lower than mean scores of sum of subtests of VIQ or PIQ (p<.05). Regarding comorbidities, children with externalizing disorders exhibited. Lower scores on 'information and vocabulary' than other groups (p=.008). Children with no comorbidities exhibited higher scores on 'similarities and object assembly' than children with externalizing/internalizing disorders (p=.001) and also on 'comprehension' than children with externalizing disorders (p=.006). For subtypes of ADHD, children with hyperactive-impulsive type had higher scores on 'comprehension' than children with inattentive and combined type (p=.004). CONCLUSION: These results suggested that intelligence test might provide useful information for assessing ADHD.