Attention-deficit/hyperactivity disorder: the impact of methylphenidate on working memory, inhibition capacity and mental flexibility

Abstract

Objective To compare children with attention-deficit/hyperactivity disorder (ADHD), before and after the use of methylphenidate, and a control group, using tests of working memory, inhibition capacity and mental flexibility. Methods Neuropsychological tests were administrated to 53 boys, 9–12 years old: the WISC-III digit span backward, and arithmetic; Stroop Color; and Trail Making Tests. The case group included 23 boys with ADHD, who were combined type, treatment-naive, and with normal intelligence without comorbidities. The control group (n = 30) were age and gender matched. After three months on methylphenidate, the ADHD children were retested. The control group was also retested after three months. Results Before treatment, ADHD children had lower scores than the control group on the tests (p ≤ 0.001) and after methylphenidate had fewer test errors than before (p ≤ 0.001) Conclusion Methylphenidate treatment improves the working memory, inhibitory control and mental flexibility of ADHD boys.

Effects of methylphenidate on executive functioning in children and adolescents with ADHD after long‐term use: a randomized, placebo‐controlled discontinuation study

“…It should be noted that working memory underlies the central executive component of executive functioning (Engle, Laughlin, Tuholski, & Conway, 1999) and is the one executive function task that is most consistently impaired in children with ADHD (Kofler et al, 2019). However, previous studies did report positive effects of methylphenidate on response inhibition, attentional flexibility and psychomotor speed in treatment-na€ ıve children with ADHD (Bolfer et al, 2017;Coghill, Seth, et al, 2014;Konrad, Neufang, Fink, & Herpertz-Dahlmann, 2007;Pietrzak et al, 2006). Our null findings could result from a diminishing effect after long-term use due to developing tolerance for methylphenidate (Wang et al, 2013), although an assessment prior to starting methylphenidate treatment would be necessary to confirm this.…”

Delay Aversion and Executive Functioning in Adults With Attention-Deficit/Hyperactivity Disorder: Before and After Stimulant Treatment

“…Thus, for working memory and planning, 3 previous studies have reported significant, positive effects but were all uncontrolled ( Fallu et al, 2006 ; Ginsberg et al, 2012 ; Ni et al, 2013 ). Controlled children’s studies have found mixed effects of methylphenidate treatment for these functions (e.g., Coghill et al, 2007 ; Cristiana et al, 2017 ; Kortekaas-Rijlaarsdam et al, 2017 ; Morell and Expósito, 2017 ). Two randomized control trial (RCT) studies indicate positive, significant effects of methylphenidate for measures of response inhibition ( Bouffard et al, 2003 ; Boonstra et al, 2005 ), but these and 2 additional studies ( Ni et al, 2013 ; Bron et al, 2014 ) also report nonsignificant findings.…”

Is there an Effect of Serotonin on Attention Deficit Hyperactivity Disorder

“…This result is consistent with the results of previous studies which found that the prevalence of ADHD was greater in boys (6,20,21) . Psychostimulant methylphenidate (MPH) and amphetamine (AMPH) are the first-line ADHD drug choice (22)(23)(24)(25) Both of these drugs primarily work on dopamine (D2) and noradrenaline (NA) system, but not on the serotonin system (8,26) . More than half of the subjects did not respond positively to the administration of this psychostimulant (6,27) Not all parents agree with methylphenidate that affects appetite and inhibits growth when given to their children and also the risk of drug dependence or abuse on long-term use with adolescent subject (28) .…”