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.
Key Words
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Article info
Publication history
Published online: September 25, 2008
Accepted:
August 14,
2008
Received in revised form:
August 3,
2008
Received:
May 29,
2008
Identification
Copyright
© 2008 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
