|Ph.D Student||Agay Nirit|
|Subject||Non-Selective Effects of Methylphenidate (Ritalin) on|
Cognitive Ability and Decision-Making of Adults
with ADHD and Healthy Adults
|Department||Department of Industrial Engineering and Management||Supervisor||Professor Eldad Yechiam|
|Full Thesis text|
Methylphenidate (MPH; Ritalin) is one of the most common treatments for Attention-deficit-hyperactivity-disorder (ADHD) in children and adults. Currently, it is being prescribed solely for ADHD and narcolepsy. High prevalence of illicit use of this psychoactive stimulant (students for example) raises public and professional debates concerning practical and ethical considerations of cognitive enhancement. However, no study compared the effect of a single-dose of MPH on adults with ADHD to its effect on healthy adults, and only a single study has compared it in children. In this research we compared a group of adults with ADHD to a matched group of non-ADHD adults in their response to a single-dose of MPH, in two placebo-controlled double-blind randomized trials. The effect of MPH was measured through a battery of computerized tasks assessing sustained attention, working memory, and experience-based decision making. Results of both studies demonstrate a non-selective enhancing effect of MPH on working-memory and on measures of sustained attention. However, MPH did not alter decision-making behavior of either group. We therefore suggest that the cognitive-enhancing effect of MPH is task specific, and is general rather than ADHD-selective. Our findings are reviewed together with the children's study mentioned above, which lends more proof to our claim. We therefore cautiously suggest that MPH may be beneficial for individuals with an initially low cognitive performance in the above measures, rather than those strictly diagnosed with ADHD.