Effects of a Single Dose of Methylphenidate on Cognition in Adults with ADHD and Predictive Therapeutic Response

Attention Deficit Hyperactivity Disorder (ADHD) affects about 60 % of adults who suffered from ADHD in childhood. These patients complain about organization and planning difficulties, procrastination, and thoughtlessness or memory troubles. Methylphenidate (MPH) is a common off-label treatment in European countries. The aim of this study was to assess the neuropsychological effects of a single dose of MPH on different attention components and on executive functions by using a computerized Attention Assessment Battery. Clinical and self-rating visual analogical scales were used. We also analysed if acute effects of a test dose of MPH on cognitive parameters may predict long-term outcomes with MPH medication. One hundred and one diagnosed adult patients were enrolled into this study. Neuropsychological evaluations were performed at baseline, after a single dose (“MPH Test”) and 6 months after chronic MPH treatment with an adequate dose. Compared with baseline, a single dose of MPH resulted in a statistically significant improvement in working memory performance, visual scanning, phasic and selective attention, sustained attention as well as executive functions in terms of number of mistakes and omissions. Reaction times also significantly decreased in most of these tasks. Statistically significant effects were also observed regarding the subjective assessments. These improvements on cognitive functions and subjective feelings were still observed after 6 months of MPH treatment. Positive impacts on everyday life were noticed regarding the clinical scales compared to the baseline. Our results suggest that the “MPH test” would be useful in predicting subsequent responses to methylphenidate in ADHD adult patients