Olfactory Impairments in Child Attention-Deficit/Hyperactivity Disorder

Objective: This study compared unilateral olfactory identification abilities in children with and without attention-deficit/hyperactivity disorder (ADHD) and evaluated the utility of the University of Pennsylvania Smell Identification Test (UPSIT) as a potential screening tool for the diagnosis of ADHD.

Method: Subjects comprised 44 children with DSM-IV ADHD (aged 7-16 years) from 2 Melbourne, Australia, hospital outpatient clinics and 44 healthy children matched for age and sex. The children were assessed from March 2004 to October 2004 for olfactory identification ability using the UPSIT, and behavioral data were gathered using the Rowe Behavioral Rating Inventory. Background and demographic data were also obtained through hospital records and parental interview.

Results: Children with ADHD demonstrated significantly poorer olfactory identification ability compared to healthy controls (p < .01). A significant right nostril advantage for smell identification was evident in the control group (p < .01), whereas significant right nostril impairment was evident among the children with ADHD (p < .01).

Conclusion: The results provide the first evidence of olfactory identification deficits in children with ADHD. As such deficits implicate orbitofrontal regions, this finding is consistent with previous reports of prefrontal compromise in children with ADHD.