Study etches out mechanism of drug as ADHD medication


Los Angeles [US], December 11 (ANI): For decades, doctors have used methylphenidate, a stimulant drug sold as Ritalin and Concerta, to treat children with attention deficit/hyperactivity disorder (ADHD), making it one of the most commonly prescribed treatments aimed at the central nervous system. Researchers might believe they understand the mechanism of methylphenidate’s action in the brain. However, it is not yet possible to know for sure.

Recent research has been published in the journal Biological Psychiatry. Cognitive Neuroscience. Neuroimaging and Cognitive Neuroscience’ seeks to bridge this knowledge gap and better understand the interaction between methylphenidate cognitive control networks, attentional behavior, and neuroimaging.

Researchers have found that ADHD patients exhibit less dopamine signaling activity than people with normal attention. ADHD symptoms can be treated with methylphenidate by increasing dopamine levels in the nucleus (a hub for dopamine signals).

Brain imaging was used by researchers Yoshifumi Mozno, MD, and PhD, Weidong Cai, PhD, Vinod Meon, Vinod Menon, and Vinod Món, Ph.D. to study the effects methylphenidate. This system is important in adaptive attention control behaviors. These networks include the default mode and salience networks. ADHD children had abnormal activity in both the NAc and multiple brain networks. Dysregulation could be the reason ADHD symptoms occur. These symptoms can be alleviated by correcting dysregulation.

“Our findings show that methylphenidate may alter the spontaneous neural activity of reward- and cognitive control system systems in ADHD children. Medication-induced cognitive network changes are more likely to trigger sustained attention. Our research reveals a novel brain mechanism that underlies methylphenidate therapy for ADHD. These findings also help to design biomarkers for evaluating treatment results. Dr. Menon, Department of Psychiatry & Behavioral Sciences, Stanford University School of Medicine.

The researchers used functional magnetic resonance imaging (fMRI) to evaluate the effects of methylphenidate on spontaneous brain activity in 27 ADHD kids and 49 normal-developing controls. The researchers made two visits to ADHD children for each treatment. One was with methylphenidate and one with placebo. Children in development rarely received either medication nor placebo. ADHD children completed a standard task that assessed sustained attention outside of the scanner. Researchers also examined whether methylphenidate could have an effect on spontaneous brain activity in another group.

It is not surprising that children did better on attention tasks when they were medicated. Researchers speculated that methylphenidate administration may have led to an increase in spontaneous neural activity within the default mode, salience and NAc networks. ADHD children with more brain activity in their default network were more likely to complete the attention tasks. These results were replicated across two cohorts. These results support the idea that methylphenidate might be able relieve ADHD symptoms by its effects on the NAc cognitive and triple network cognitive.

Cameron Carter, MD is the editor for Biological Psychiatry. Cognitive Neuroscience. Neuroimaging. He stated that the results using the widely-used technique of resting condition functional MRI confirmed the positive effects methylphenidate has on ADHD children. They also showed that methylphenidate may be acting through an increase in brain activity, which could explain the increased dopamine levels in NAc.

This research advances our understanding of ADHD and brain cognitive control networks. This research also shows how methylphenidate interacts with these networks to shift behavior. These findings could be used to guide future brain imaging research to determine the response to treatments. (ANI)