Benefits of ADHD Medication Include Brain Growth, Fewer Serious Accidents

July 29, 2025

Stimulant and nonstimulant medication use decreases the risk of adverse outcomes and promotes brain development in individuals diagnosed with ADHD, new research reveals.

According to a new longitudinal, population-based study published in JAMA Psychiatry, ADHD medication was associated with the following:

• 15% to 29% reduction in risk for self-harm
• 7% to 13% reduction in risk for unintentional injury
• 13% to 29% reduction in risk for traffic crashes
• 16% to 27% reduction in risk for crime ¹

The researchers used Swedish National Registers to identify nearly 250,000 individuals aged 4 to 64 years who used stimulant and nonstimulant ADHD medications between 2006 and 2020. For the study, they tracked the participants’ incidents of self-harm, unintentional injury, traffic crashes, and criminal activity during medicated and unmedicated periods across three time periods: 2006 to 2010, 2011 to 2015, and 2016 to 2020.

The findings do not suggest that ADHD medication becomes less effective over time. However, the researchers note that more people with milder ADHD symptoms are being prescribed medication, and those people often do not experience the same magnitude of benefit from ADHD medication as do people with more significant impairments. In short, the average effect size of medication gets diluted as people with less severe symptoms of ADHD receive treatment.

“With an increasing number of ADHD diagnoses and medication prescriptions, it is likely that the people being diagnosed and treated for ADHD today will have presented with less severe ADHD, showing less symptoms or fewer impairments than those who were diagnosed and treated 15 years ago,” wrote the researchers.

They found prescription prevalence increased from an average of 0.4% during 2006-2010 to 1% during 2011-2015, and then to 1.6% during 2016-2020 (from 0.8% to 2.4% in children and from 0.2% to 1.1% in adults). The study reported that the percentage of ADHD medication prescriptions for women and girls, aged 15 to 44, grew from 0.9% in 2003 to 4% in 2015. Females experienced the strongest protective effects from medication from 2006 to 2010. Women and girls have been historically under-identified and underdiagnosed for ADHD.². Therefore, the study reasons, only women and girls with the most severe ADHD symptoms were likely to get diagnosed and treated during that period.

“Increases in prescriptions are not a response to actual rises in ADHD prevalence,” the researchers wrote, “but rather reflect improved research and diagnostic tools, changes in parental perception of impairment, and increased clinician and community awareness of ADHD.”

A systematic review published last month in the Journal of Attention Disorders found no significant increase in ADHD prevalence rates among children and adults from 2020 to 2024 compared to earlier time periods.³

“Even though the magnitude of associations between ADHD medication use and risk of these more distal outcomes appears to decrease as the rates of prescription increase, there are still clear benefits associated with ADHD medication use,” the researchers wrote.

ADHD Medication Provides Age-Dependent Effects on Developing Brains

Findings from a new longitudinal magnetic resonance imaging (MRI) study published in Progress in Neuro-Psychopharmacology & Biological Psychiatry show that early and consistent use of methylphenidate (brand names: Ritalin, Focalin) influences frontal lobe development in the brains of children with ADHD.⁴

The study involved 89 participants with ADHD and 91 without ADHD, divided into three groups: early-exposure (methylphenidate exposure before age 12), late-exposure (methylphenidate exposure after age 12), and control.

Researchers established baseline brain scans using MRI. Follow-up MRIs, five years later, indicated brain growth in the early-exposure group, suggesting that higher cumulative dosages were associated with increased frontal lobe volumes. Parent surveys also revealed significant improvements in oppositional symptoms (e.g., argumentative, defiant) among the early-exposure group. However, the late-exposure group did not demonstrate any significant changes in brain volume or symptom reduction.

“The findings suggest that initiating methylphenidate treatment earlier, particularly before the age of 12, may be more effective in driving structural brain changes and potentially normalizing the atypical brain development associated with ADHD,” the researchers wrote. “This underscores the importance of early intervention and treatment initiation in children with ADHD.”

ADHD Medication Faces Scrutiny

ADHD medication use has faced increased criticism by the MAHA Commission, spearheaded by Health and Human Services (HHS) Secretary Robert F. Kennedy, Jr. In May, the commission released The MAHA Report, which falsely claimed that ADHD is contributing to a “crisis of overdiagnosis and treatment” in American children and that stimulant medication use does “not improve outcomes long-term.” These recent studies prove otherwise.

Many ADHD experts view the increases in ADHD diagnoses and medication prescriptions positively. “Why isn’t that evidence of improvement in good public mental health?” asks Russell Barkley, Ph.D., a leading authority on ADHD, in a video on his YouTube channel. “The fact that there is a rise in the occurrence of a particular treatment does not provide prima facie evidence that there is something bad, wicked, evil, wrong going on here; it simply means that, over time, we are getting closer and closer to identifying conditions that produce harm in individuals, and that we try to alleviate that harm and suffering.”

In August, the MAHA Commission plans to release policy recommendations to “begin reversing the childhood chronic disease crisis” with an anticipated focus on ADHD, autism, diabetes, obesity, and other conditions impacting American youth.

Many ADDitude readers have expressed fear that the commission’s actions could restrict access to prescription medication and its preventative benefits.

“I can’t even think about this without feeling ill,” said an ADDitude reader in Michigan. “On the surface, I look like a normal, functioning professional with an advanced degree. I am fortunate to have landed a job with a six-figure salary, but I can’t tell you how many nights I spent curled up crying during the stimulant shortages because I was terrified that I would lose my job if I couldn’t function without my medication. Not to mention how hopeless and embarrassed I felt having to desperately call every local pharmacy to see if they had medication in stock. We need to broaden access — not limit it.”

“I am terrified of the outcome of this so-called assessment,” said an ADDitude reader in Texas. “For several years, we’ve tried to find the right drug combination for my daughter. Now we seem to have it, and I’m afraid it will be stripped away in a couple of months. We both have ADHD, take stimulants, as well as meds for anxiety and depression. If they are no longer available to us, I will attempt to migrate to Canada, seeking asylum based on the fact that living in the U.S. would put our health severely at risk.”

The JAMA Psychiatry and Progress in Neuro-Psychopharmacology & Biological Psychiatry studies build on an arsenal of scientific evidence dating back more than 40 years supporting the life-saving benefits of ADHD medication.

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