Methylphenidate May Affect Brain Development of Children with ADHD
A small study shows that boys taking the ADHD medication methylphenidate experienced an increase in white matter — the location of the brain’s nerve fibers and myelin sheath that control the speed and transmission of electrical nerve signals — while adult men taking the same medication did not.
August 14, 2019
The ADHD medication methylphenidate may affect the brain chemistry of children with the condition, according the results of a new study.1 Research published in Radiology suggests that methylphenidate (MPH) use can affect specific tracts in the white brain matter of boys with attention deficit disorder (ADHD or ADD). White matter, found in the subcortical tissues of the brain, contains nerve fibers surrounded by a myelin sheath that helps to speed up the transmission of nerve signals.
“Recent neuropsychological studies suggest that people with ADHD process information more slowly, and there is more ‘noise’ during their processing,” according to Joel Nigg, Ph.D. “This may be related to immaturity of myelin fibers, which makes the axon’s neural transmission between certain brain circuits less efficient.”2
The recent study, conducted by researchers in the Netherlands, used MRI results to assess white matter in boys and young men treated with MPH or a placebo. Boys who had been treated with MPH displayed increased white matter, while the adults who had been treated with MPH did not. Changes were not present in either age group treated with placebo.
Fifty boys (age 10-12) and 49 men (age 23-40) received a 16-week course of either MPH or a placebo. Each participant received an MRI using Diffusion Tensor Imaging — a technique that allows researchers to estimate the location, orientation, and fractional anisotropy (a measure of connectivity in the brain) of the brain’s white matter tracts — before beginning treatment, and again one week after the treatment had concluded. Prior to the study, none of the participants had taken MPH.
Analysis revealed greater increase in fractional anisotropy in boys treated with MPH than in the other three groups. The affect appears to be age dependent, since the adults treated with MPH did not experience a similar increase.
1 Bouziane, Cheima, Filatova, Olena G., Schrantee, Anouk, Caan, Matthan W. A. Vos, Frans M., Reneman, Liesbeth, “White Matter by Diffusion MRI Following Methylphenidate Treatment: A Randomized Control Trial in Males with Attention-Deficit/Hyperactivity Disorder.” Radiology. (August 13 2019) https://pubs.rsna.org/doi/10.1148/radiol.2019182528
2 Nigg, Joel, “Is ADHD a Spectrum Disorder?” ADDitude. (2017) https://www.additudemag.com/adhd-is-spectrum-disorder/