Is contrast sensitivity a physiological marker in attention-deficit hyperactivity disorder?

Abstract

Attention-deficit hyperactivity disorder (ADHD) is one of the most common childhood-onset psychiatric disorders. Although the etiology is complex and has not yet been clarified, dopamine is thought to play a role in the etiology. Methylphenidate (MPH) is a psychostimulant drug used as first-line treatment for ADHD and it inhibits dopamine and norepinephrine reuptake transporters. Dopamine also has an effect on retina and contrast sensitivity. Despite evidence indicating the effects of dopamine on contrast sensitivity, the results of studies examining contrast sensitivity in ADHD patients are inconsistent. Also, no studies have been encountered examining the possible effect of MPH on contrast sensitivity. The hypotheses of this study are that children with ADHD who have not used MPH will have lower contrast sensitivity levels than the members of the control group, that contrast sensitivity levels increase after the use of MPH, and that contrast sensitivity is a potential physiological marker for ADHD. The study was conducted with 30 children with ADHD and 30 children without ADHD. Psychiatric evaluations of the participants were conducted with the Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime-Turkish version, Conner's Parent Rating Scale-Revised Short form and the Turgay DSM-IV-based Child and Adolescent Behavioral Disorders Screening and Rating Scale. Photopic contrast sensitivity was measured using the Functional Acuity Contrast Test (FACT). Results showed that FACT mean values of the control group were significantly higher than those of the ADHD group (pre-treatment) in all spatial frequencies. In four spatial frequencies (CPD 1.5, 3, 12 and 18), the FACT mean values of the control group were significantly higher than the ADHD group (during the OROS-MPH treatment). At all spatial frequencies, the mean values of the ADHD group during the OROS-MPH treatment were significantly higher than before the OROS-MPH treatment. In conclusion, the present study showed that contrast sensitivity is low in children with ADHD and increases significantly after OROS-MPH medication, but still did not reach the levels of the children without ADHD. Our findings suggest that contrast sensitivity may be a potential physiological marker in ADHD.

• Authors: Yunus Emre Dönmez, Özlem Özel Özcan, Cem Çankaya, Merve Berker, Pamuk Betül Ulucan Atas, Pelin Nazlı Güntürkün, Osman Melih Ceylan
• Journal: Medical hypotheses (Med Hypotheses) Vol. 145 Pg. 110326 (Dec 2020) ISSN: 1532-2777 [Electronic] United States
• PMID: 33075582 (Publication Type: Journal Article)
• Copyright: Copyright © 2020 Elsevier Ltd. All rights reserved.

Chemical References

• Central Nervous System Stimulants
• Delayed-Action Preparations
• Methylphenidate

Topics

• Adolescent
• Attention Deficit Disorder with Hyperactivity (diagnosis, drug therapy)
• Central Nervous System Stimulants
• Child
• Contrast Sensitivity
• Delayed-Action Preparations
• Humans
• Methylphenidate
• Treatment Outcome