A large Swedish study suggests that attention deficit/hyperactivity disorder (ADHD) meds might do more than ease core symptoms. It could also curb more dramatic mental health risks, from criminal convictions to substance abuse to suicidal behavior.
Researchers at Karolinska Institutet and partner institutions sifted through the health, crime, and prescription records of more than 148,000 people between 6 and 64 who’d received an ADHD diagnosis. A little more than half of the patients began ADHD medication within three months of diagnosis. Clinicians prescribed methylphenidate more frequently than any other treatment.
The team used a “target trial emulation” design to track outcomes for two years.
Fewer Serious Events
Compared with those who didn’t start medication, those who began (and stuck with) treatment boasted lower rates of a first recorded episode of:
- Suicidal behaviours: 14.5 vs 16.9 per 1,000 person-years, a 17% relative reduction.
- Substance misuse: 58.7 vs 69.1; 15% reduction.
- Transport accidents: 24.0 vs 27.5; 12% reduction.
- Criminal convictions: 65.1 vs 76.1; 13% reduction.
The association with accidental injuries failed to reach statistical significance for first events.
When researchers looked at recurrent events – reflecting the grim reality that so many people endure multiple episodes – medication use revealed a connection to reductions across all five outcomes, including accidental injuries.
Rates of repeat substance misuse and criminal convictions hovered around 25% lower in the medicated group, while recurrent suicidal behaviours appeared to be 15% lower.
The Strongest Benefits
The researchers also discovered that the protective effects seemed to be the most significant among patients with a history of the measured outcome.
For example, among those who’d previously engaged in suicidal behaviour, medication was linked to a 21% lower rate of a repeat episode. Similar patterns held for people with histories of substance misuse, transport accidents, or criminal convictions.
Adults saw larger benefits than children and young people for substance misuse and criminality, while women experienced a stronger reduction in first criminal convictions compared to their male counterparts.
The analysis also compared stimulant medications (such as methylphenidate and lisdexamfetamine) with non-stimulants (atomoxetine and guanfacine). Stimulants lowered event rates for all five outcomes in both first and recurrent events, which backs clinical guidelines that recommend them as first-line therapy.
But Why?
The study’s authors argue that these results probably reflect the medications’ impact on core ADHD symptoms, which might (in turn) curb the likelihood of risky behaviour, injury, or legal trouble. For instance, better focus could reduce driving errors, while greater self-control might prevent impulsive acts of aggression or substance use.
“One possible explanation is that the medication leads to reduced impulsivity, which can reduce the risk of crime by curbing aggressive behavior, as well as improved attention, which can reduce the risk of traffic accidents by reducing distractions,” the study’s last author, Zheng Chang, PhD, a researcher at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet, explained. “These results provide evidence that ADHD medication can affect important health and societal outcomes, which should be taken into account both in clinical practice and in the public debate on drug treatment.
Earlier observational studies hinted at similar benefits, but those usually relied on smaller patient groups or more vulnerable study designs. By including the entire ADHD population in Sweden and applying a strict analytical framework, this new study offers results that might be closer to what randomised controlled trials would find in everyday clinical settings.
Moving Forward
The study, published in The BMJ, provides population-level evidence that ADHD medication could confer broader protective effects beyond symptom control. The authors argue that these benefits (especially for those with a history of serious events) warrant consideration.
Finally, the authors insist that these results should inform policy debates, including whether methylphenidate should be added to the World Health Organization’s list of essential medicines.
“These findings are relevant for patients, clinicians, and policymakers weighing the benefits and risks of ADHD drug treatment,” they wrote.
Further Reading
How Music Helps ADHD Minds Focus and Feel
