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.