Dose-related effect of methylphenidate on stopping and changing in children with attention-deficit/hyperactivity disorder.
OBJECTIVE
The effect of methylphenidate (MPH) on inhibitory control as assessed by the stop task in children with attention-deficit/hyperactivity disorder (ADHD) could be influenced by task difficulty and may be mediated by attention.


METHODS
Fifteen children with ADHD performed the stop and the change task after placebo, 0.5 and 1.0 mg/kg MPH in a within-subject design.


RESULTS
Linear-trend analysis showed a similar effect of MPH in both tasks and a stronger effect for inhibitory control than for attention. Furthermore, a correlation was found between blood serum metabolites of norepinephrine and dopamine for attentional measures and inhibitory control measures, respectively.


CONCLUSIONS
In children with ADHD MPH could act primarily on inhibitory control, and is not influenced by task difficulty. Also, attention and inhibitory control could have differential pharmacological profiles.
Department of Psychopharmacology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands. malijffi@utmb.edu
Marijn
M
Lijffijt
J Leon
JL
Kenemans
Annemiek
A
ter Wal
Elise H
EH
Quik
C
C
Kemner
Herman
H
Westenberg
Marinus N
MN
Verbaten
Herman
H
van Engeland
D000293:Adolescent; D001288:Attention / Q000187:drug effects*; D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood / Q000188:drug therapy* / Q000523:psychology; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D002648:Child; D002652:Child Behavior / Q000187:drug effects / Q000523:psychology; D004298:Dopamine / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D007389:Internal-External Control; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood; D011930:Reaction Time / Q000187:drug effects; D013647:Task Performance and Analysis
D000697:Central Nervous System Stimulants; D008774:Methylphenidate; D004298:Dopamine; D009638:Norepinephrine