None of the mediators or moderators tested affected methylpheni date efficacy .
Academic improvements were small compared to symptom improvements ; qualitative changes limited to math .
Academic improvement is amongst the most common treatment targets when prescribing stimulants to children with ADHD .
Previous review s on stimulant-related academic improvements are inconclusive and focus on task engagement .
Recent literature suggests outcome -domain-specific medication effects that are larger for productivity than for accuracy .
The aims of this study are quantifying methylpheni date effects on academic productivity and accuracy for math , reading , spelling ; exploring the mediating or moderating effects of symptom improvements , demographic- , design - and disorder-related variables .
Mediators of Methylphenidate Effects on Math Performance in Children with Attention-Deficit Hyperactivity Disorder
Objective : Stimulant medications , such as methylpheni date ( MPH ) , improve the academic performance of children with attention-deficit hyperactivity disorder ( ADHD ) . However , the mechanism by which MPH exerts an effect on academic performance is unclear . We examined MPH effects on math performance and investigated possible mediation of MPH effects by changes in time on-task , inhibitory control , selective attention , and reaction time variability . Methods : Children with ADHD aged 7 to 11 years ( N = 93 ) completed a timed math worksheet ( with problems tailored to each individual 's level of proficiency ) and 2 neuropsychological tasks ( Go/No-Go and Child Attention Network Test ) at baseline , then participated in a 4-week , r and omized , controlled , titration trial of MPH . Children were then r and omly assigned to their optimal MPH dose or placebo for 1 week ( administered double-blind ) and repeated the math and neuropsychological tasks ( posttest ) . Baseline and posttest videorecordings of children performing the math task were coded to assess time on-task . Results : Children taking MPH completed 23 more math problems at posttest compared to baseline , whereas the placebo group completed 24 fewer problems on posttest versus baseline , but the effects on math accuracy ( percent correct ) did not differ . Path analyses revealed that only change in time on-task was a significant mediator of MPH 's improvements in math productivity . Conclusions : MPH-derived  math productivity improvements may be explained in part by increased time spent on-task , rather than improvements in neurocognitive parameters , such as inhibitory control , selective attention , or reaction time variability
None of the mediators or moderators tested affected methylpheni date efficacy .
Academic improvements were small compared to symptom improvements ; qualitative changes limited to math .
Academic improvement is amongst the most common treatment targets when prescribing stimulants to children with ADHD .
Previous review s on stimulant-related academic improvements are inconclusive and focus on task engagement .
Recent literature suggests outcome -domain-specific medication effects that are larger for productivity than for accuracy .
The aims of this study are quantifying methylpheni date effects on academic productivity and accuracy for math , reading , spelling ; exploring the mediating or moderating effects of symptom improvements , demographic- , design - and disorder-related variables .