Distinct Latent Profiles of Working Memory and Processing Speed in Adults with ADHD.

This study examined the neuropsychological profile of patients with Attention-Deficit/Hyperactivity Disorder (ADHD) based on Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) working memory and processing speed indices. We aimed to establish whether distinct ADHD subtypes emerge based on neuropsychological testing and determine whether ADHD subgroups differ based on neurocognitive and demographic factors in 179 adult patients with ADHD. Latent Profile Analysis (LPA) revealed four discrete latent subgroups within the sample, each with distinct patterns of working memory and processing speed. Classes significantly differed in demographically predicted IQ, education, and self-reported depression and anxiety. Results reveal heterogeneity in cognitive performance in adult ADHD.

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.