Masking effect of high IQ on the Rey Auditory Verbal Learning Test in an adult sample with attention deficit/hyperactivity disorder.

OBJECTIVE

High intelligence (IQ) adults with attention-deficit/hyperactivity disorder (ADHD) often perform better on neuropsychological tests relative to average IQ adults with ADHD, despite commensurate functional impairment. This study compared adults with ADHD and high versus average IQ on the Rey Auditory Verbal Learning Test (RAVLT) to specifically assess this proposed masking effect of IQ on verbal learning/memory performance among those undergoing neuropsychological evaluation.

METHOD

RAVLT performance between patients with ADHD and average versus high Test of Premorbid Function-estimated IQ were compared. Latent growth curve modeling (LGCM) evaluated learning acquisition across trials.

RESULTS

RAVLT total learning, immediate, and delayed free recall performances were significantly better in the high IQ relative to the average IQ group. LGCM showed similar quadradic growth trajectories for both IQ groups. Both groups reported equivalent symptom severity and functional complaints in childhood and adulthood.

CONCLUSIONS

Adults with ADHD and high IQ performed normally on a verbal learning/memory test compared to adults with average IQ, who scored 0.5-1.0 standard deviations below the mean. These results suggest a masking of performance-based memory deficits in the context of higher IQ in adults with ADHD, supporting growing evidence that higher IQ masks neurocognitive deficits during the assessment of adults with ADHD.