Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Germany.
J Psychiatr Res. 2011 Nov;45(11):1463-70. doi: 10.1016/j.jpsychires.2011.05.011.
Olfaction and attention-deficit-/hyperactivity disorder (ADHD) are mediated by dopamine metabolism and fronto-temporal functioning converging in recent findings of increased olfactory sensitivity in children with ADHD modulated by methylphenidate (MPH) and altered frontal and temporal oxygenation in adults with ADHD.
We investigated olfactory sensitivity, discrimination, and identification (Sniffin' Sticks) in 27 children and adolescents with ADHD under chronic MPH medication and after a wash-out period of at least 14 half-lives in balanced order and 22 controls comparable for handedness, age, and intelligence. In addition, inferior frontal and temporal oxygenation was measured by means of functional near-infrared spectroscopy (fNIRS) during the presentation of 2-phenylethanol. Group differences in regard to sex distribution were statistically controlled for by analysis of covariance.
Patients did not differ from controls in any olfactory domain under treatment with MPH. Cessation of medication led to a significant increase in olfactory discrimination. Controls displayed typical inferior frontal and temporal brain activity in response to passive olfactory stimulation, while brain oxygenation was diminished in the patient group when assessed without medication. Under medication ADHD patients showed a trend for a normalisation of brain activity in the temporal cortex.
The here reported effects of MPH cessation on olfactory discrimination and frontal and temporal oxygenation along with previous findings of increased olfactory sensitivity in medication-naïve ADHD children and its normalisation under chronic MPH treatment lead to the conclusion that MPH exerts differential chronic effects vs. acute cessation effects on altered olfactory function in ADHD. These effects are most probably mediated by modulation of the dopaminergic system.
嗅觉和注意缺陷多动障碍（ADHD）受多巴胺代谢和额颞叶功能的调节，最近的研究发现，ADHD 儿童的嗅觉敏感性增加，这种增加受哌甲酯（MPH）调节，ADHD 成人的额颞叶氧合作用改变。
我们在 27 名慢性 MPH 治疗的 ADHD 儿童和青少年以及至少 14 个半衰期的洗脱期后，以平衡的顺序对嗅觉敏感性、辨别和识别（Sniffin' Sticks）进行了研究，并与 22 名具有可比性的对照组进行了比较，包括惯用手、年龄和智力。此外，在 2-苯乙醇呈现期间，通过功能近红外光谱（fNIRS）测量下额和颞叶的氧合。通过协方差分析对性别分布的组间差异进行了统计学控制。
在 MPH 治疗下，患者在任何嗅觉领域均与对照组无差异。停药后嗅觉辨别能力显著提高。对照组在被动嗅觉刺激下表现出典型的下额和颞叶脑活动，而在未服药时，患者组的脑氧合减少。在服药时，ADHD 患者颞叶皮质的脑活动呈正常化趋势。
这里报道的 MPH 停药对嗅觉辨别和额颞叶氧合的影响，以及之前在未用药的 ADHD 儿童中发现的嗅觉敏感性增加及其在慢性 MPH 治疗下的正常化，导致结论是 MPH 对 ADHD 改变的嗅觉功能具有慢性和急性停药作用的差异。这些作用最有可能是通过调节多巴胺能系统介导的。
