Sex differences in attentional performance and their modulation by methylphenidate in children with attention-deficit/hyperactivity disorder.
BACKGROUND
Still little is known about neuropsychological differences between boys and girls with attention-deficit/hyperactivity disorder (ADHD) and whether there are sex-specific differences in the modulation of attentional performance by methylphenidate (MPH).


METHODS
In this study, 27 males and 27 females between 8-12 years old and with ADHD were investigated in a double-blind, placebo-controlled trial on five computerized attention tests (0.25 vs. 0.5 mg/kg MPH as a single dose, versus placebo).


RESULTS
Boys and girls with ADHD did not differ with respect to age, intelligence quotient (IQ), symptom severity, co-morbidity patterns, and ADHD subtype. However, ADHD boys were more impulsive on a sustained attention task, whereas girls with ADHD had more deficits on tasks measuring selective attention. Attentional performance increased differentially as a function of MPH dose, with some tasks showing linear improvement with higher dosage whereas more complex tasks in particular showed inverse U-shaped patterns of MPH effects. However, these effects were comparable between girls and boys.


CONCLUSIONS
Our data suggest that there are some gender differences in attentional performance in subjects with ADHD in a clinical sample, even if symptom severity and co-morbidity are controlled; however, modulation of attention by MPH does not seem to differ between sexes.
Günther
Thomas
T
Child Neuropsychology Section, Department of Child and Adolescent Psychiatry, University Hospital of the RWTH Aachen, Aachen, Germany. thomas.guenther2@post.rwth-aachen.de
Herpertz-Dahlmann
Beate
B
Konrad
Kerstin
K
D001288:Attention / Q000187:drug effects*; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000503:physiopathology; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000187:drug effects; D012720:Severity of Illness Index; D012737:Sex Factors; D016896:Treatment Outcome
D000697:Central Nervous System Stimulants; D008774:Methylphenidate