Researchers wanted to understand how stimulant medication changes brain activity in ADHD, since the drugs are widely used but their mechanism is not fully understood. They ran a brain scan study using functional MRI in 20 adolescents with ADHD who had not taken medication before. Each person was scanned under both methylphenidate and a placebo while doing tasks that involved stopping a response, holding information in mind, and judging time.
In that scan study, methylphenidate increased activity in the inferior frontal cortex and insula on both sides of the brain during the inhibition and time tasks, but it did not change activity in the networks used for the working memory task. The medication was given as part of a controlled trial, not as a general recommendation, and the study did not report a specific dose to follow.
The researchers also combined results from 14 earlier brain scan datasets covering 212 children with ADHD. Across these studies, stimulants most reliably raised activity in the right inferior frontal cortex and insula, and this pattern held when they looked only at methylphenidate. Using a less strict statistical cutoff, they also saw more activity in the putamen. The authors note these regions are central to cognitive control and are among the most consistently reported areas of difference in ADHD, and they suggest these brain effects may help explain why the medication helps some people.
Because this finding concerns a prescription medication, decisions about whether it is appropriate belong with a qualified clinician who knows the person's history.
Source: Rubia K, Alegria A, Cubillo A, et al. Effects of Stimulants on Brain Function in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis. Biological Psychiatry (2014). doi:10.1016/j.biopsych.2013.10.016
Source: Rubia K, Alegria A, Cubillo A, et al.. Effects of Stimulants on Brain Function in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis. Biological Psychiatry (2014). doi:10.1016/j.biopsych.2013.10.016