RESULTS The fMRI analysis showed that methylpheni date significantly enhanced activation in bilateral inferior frontal cortex (IFC)/insula during inhibition and time discrimination but had no effect on working memory networks .
The meta- analysis , including 14 fMRI data sets and 212 children with ADHD , showed that stimulants most consistently enhanced right IFC/insula activation , which also remained for a subgroup analysis of methylpheni date effects alone .
A more lenient threshold also revealed increased putamen activation .
CONCLUSIONS Psychostimulants most consistently increase right IFC/insula activation , which are key areas of cognitive control and also the most replicated neurocognitive dysfunction in ADHD .
These neurocognitive effects may underlie their positive clinical effects
BACKGROUND Psychostimulant medication , most commonly the catecholamine agonist methylpheni date , is the most effective treatment for attention-deficit/hyperactivity disorder ( ADHD ) .
However , relatively little is known on the mechanisms of action .
Acute effects on brain function can eluci date underlying neurocognitive effects .
We tested methylpheni date effects relative to placebo in functional magnetic resonance imaging ( fMRI ) during three disorder-relevant tasks in medication-naïve ADHD adolescents .
In addition , we conducted a systematic review and meta- analysis of the fMRI findings of acute stimulant effects on ADHD brain function .
Common and unique therapeutic mechanisms of stimulant and nonstimulant treatments for attention-deficit/hyperactivity disorder.
CONTEXT Attention-deficit/hyperactivity disorder ( ADHD ) is a highly prevalent and impairing psychiatric disorder that affects both children and adults . There are Food and Drug Administration-approved stimulant and nonstimulant medications for treating ADHD ; however , little is known about the mechanisms by which these different treatments exert their therapeutic effects . OBJECTIVE To contrast changes in brain activation related to symptomatic improvement with use of the stimulant methylpheni date hydrochloride vs the nonstimulant atomoxetine hydrochloride . DESIGN Functional magnetic resonance imaging before and after 6 to 8 weeks of treatment with methylpheni date ( n = 18 ) or atomoxetine ( n = 18 ) using a parallel-groups design . SETTING Specialized ADHD clinical research program at Mount Sinai School of Medicine , New York , New York . PARTICIPANTS Thirty-six youth with ADHD ( mean [ SD ] age , 11.2 [ 2.7 ] years ; 27 boys ) recruited from r and omized clinical trials . MAIN OUTCOME MEASURES Changes in brain activation during a go/no-go test of response inhibition and investigator-completed ratings on the ADHD Rating Scale-IV-Parent Version . RESULTS Treatment with methylpheni date vs atomoxetine was associated with comparable improvements in both response inhibition on the go/no-go test and mean ( SD ) improvements in ratings of ADHD symptoms ( 55 % [ 30 % ] vs 57 % [ 25 % ] ) . Improvement in ADHD symptoms was associated with common reductions in bilateral motor cortex activation for both treatments . Symptomatic improvement was also differentially related to gains in task-related activation for atomoxetine and reductions in activation for methylpheni date in the right inferior frontal gyrus , left anterior cingulate/supplementary motor area , and bilateral posterior cingulate cortex . These findings were not attributable to baseline differences in activation . CONCLUSIONS Treatment with methylpheni date and atomoxetine produces symptomatic improvement via both common and divergent neurophysiologic actions in frontoparietal regions that have been implicated in the pathophysiology of ADHD . These results represent a first step in delineating the neurobiological basis of differential response to stimulant and nonstimulant medications for ADHD
RESULTS The fMRI analysis showed that methylpheni date significantly enhanced activation in bilateral inferior frontal cortex (IFC)/insula during inhibition and time discrimination but had no effect on working memory networks .
The meta- analysis , including 14 fMRI data sets and 212 children with ADHD , showed that stimulants most consistently enhanced right IFC/insula activation , which also remained for a subgroup analysis of methylpheni date effects alone .
A more lenient threshold also revealed increased putamen activation .
CONCLUSIONS Psychostimulants most consistently increase right IFC/insula activation , which are key areas of cognitive control and also the most replicated neurocognitive dysfunction in ADHD .
These neurocognitive effects may underlie their positive clinical effects
BACKGROUND Psychostimulant medication , most commonly the catecholamine agonist methylpheni date , is the most effective treatment for attention-deficit/hyperactivity disorder ( ADHD ) .
However , relatively little is known on the mechanisms of action .
Acute effects on brain function can eluci date underlying neurocognitive effects .
We tested methylpheni date effects relative to placebo in functional magnetic resonance imaging ( fMRI ) during three disorder-relevant tasks in medication-naïve ADHD adolescents .
In addition , we conducted a systematic review and meta- analysis of the fMRI findings of acute stimulant effects on ADHD brain function .