Do the stimulant medications improve neuropsychological performance of college students with ADHD?

Attention Deficit/Hyperactivity Disorder (ADHD) is a prevalent disorder estimated to affect 5% to 10% of school-aged children and approximately 4% of adults worldwide. The defining symptoms are hyperactivity, impulsivity and inattention, which are all acutely reduced by the stimulant medications, methylphenidate and amphetamine. Nevertheless, in spite of robust short-term efficacy, long-term follow-up studies fail to show drug effects on academic achievement of ADHD students. Because recent research indicates that the medications also do not normalize performance of ADHD patients on some neuropsychological tests, we thought this might shed some light on the causes of ADHD students’ academic underachievement. There is a consistent body of evidence showing that adults with ADHD are impaired on neuropsychological tests of vigilance, verbal memory/fluency, response interference, and planning ability. In our study we used 4 neuropsychological tests: d2 Test, Control Oral Word Association Test, Stroop Tests, and Tower of London Test to test vigilance, verbal fluency, response interference, and planning ability respectively. We found that undergraduate students with ADHD did not show significant deficits except in Stroop interference, compared to normal controls. ADHD medications improved Stroop interference in ADHD students; however, medications did not help ADHD students perform better than normal students in domains of functions where no deficits were found