Improved odor sensitivity in attention-deficit/hyperactivity disorder.
BACKGROUND
Deficits in olfactory function are common features in neurodegenerative and neuropsychiatric disorders. In Parkinson's disease, olfactory deficits were found in up to 90% of patients, and there is evidence for dopaminergic dysfunction underlying these deficits. Because of the involvement of the dopamine system in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD), olfactory function was investigated in children with the disorder.


METHODS
We assessed odor threshold, identification, and discrimination in 20 children and adolescents with ADHD without medication, 20 patients with ADHD treated with methylphenidate, and 20 healthy control subjects matched for IQ, age, and sex.


RESULTS
Odor sensitivity was higher (lower threshold) in ADHD patients without medication than in healthy control subjects (p < .004; Cohen's d = 1.273), whereas medicated patients did not differ significantly from healthy control subjects. No significant differences between groups with regard to odor discrimination or identification were detected.


CONCLUSIONS
Selectively improved odor sensitivity in children with ADHD is reported for the first time, whereas odor discrimination and identification were unaffected. Stimulant medication normalized the odor sensitivity threshold. It is proposed that dopaminergic dysregulation is involved in this phenomenon.
Romanos
Marcel
M
Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Clinic of Wuerzburg, Wuerzburg, Germany. romanos@kjp.uni-wuerzburg.de
Renner
Tobias J
TJ
Schecklmann
Martin
M
Hummel
Bettina
B
Roos
Miriam
M
von Mering
Christine
C
Pauli
Paul
P
Reichmann
Heinz
H
Warnke
Andreas
A
Gerlach
Manfred
M
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000503:physiopathology; D016022:Case-Control Studies; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D009812:Odorants; D055696:Olfactory Perception / Q000187:drug effects*; D012684:Sensory Thresholds / Q000187:drug effects
D000697:Central Nervous System Stimulants; D008774:Methylphenidate