How Does ADHD Treated vs Untreated Imaging Differ? 

Research comparing ADHD treated vs untreated imaging shows that treatments especially stimulant medication can lead to observable brain differences and MRI findings, though results vary and do not replace clinical diagnosis. Treated individuals tend to show more “normalized” activity and structure in certain brain regions compared to those without treatment. 

In untreated ADHD, imaging frequently reveals reduced grey matter volume in areas such as the prefrontal cortex, basal ganglia, and cerebellum. Functional MRI (fMRI) typically shows underactivation in executive control and attention networks during tasks requiring inhibition, planning, or sustained focus. In contrast, in treated ADHD, some studies report that medication brings changes: increased activation in prefrontal areas during cognitive tasks, improved connectivity in attention and control networks, and, in some cases, modest structural differences over time, like reduced delays in cortical thinning. However, effect sizes are often small and treatment duration, age, and symptom severity influence how much imaging differences emerge.  

Common Symptom Changes Associated with Imaging Differences 

Here are examples of symptoms linked to imaging contrasts between treated and untreated ADHD, and how treatment helps: 

Better Attention and Reduced Distractibility 

Untreated individuals may show lower prefrontal cortex activity and weaker brain connectivity in attention networks, which corresponds with frequent distractions and lapses in focus. Treatment typically medication can increase activity in these regions and improve functional connectivity, helping people sustain attention more consistently. 

Improved Inhibition and Decreased Impulsivity 

Imaging studies show untreated ADHD correlates with underactivation in inhibition‑related networks. Treated ADHD often exhibits improved fMRI responses during inhibition tasks, aligning with reduced impulsiveness and fewer behavioural mistakes. Behavioural therapies (such as CBT) also help by reinforcing these improvements and building self‑control strategies. 

While imaging reveals these neuroimaging changes, it is not yet precise enough to determine treatment status or predict outcomes in individual cases. Nonetheless, comparing treated vs untreated imaging advances our understanding of how ADHD interventions impact the brain.  

Visit providers like ADHD Certify for personal consultations considering these imaging insights. 

For a deeper dive into the science, diagnosis, and full treatment landscape, read our complete guide to ADHD treated vs untreated imaging.