Sumetee Theesungnern/ Alamy Stock Photo
Researchers claim to have identified the optimal doses for each medication for attention deficit hyperactivity disorder (ADHD).
Publishing their findings in the upcoming June 2026 issue of The Lancet Psychiatry, researchers conducted a systematic review of 164 studies and a dose-response network meta-analysis of 113 randomised controlled trials (RCTs) — 45 of which involved adults and 68 of which involved children and adolescents.
“[Prior to this study], dose–effect relationships have not been comprehensively assessed across all ADHD medications and age groups, despite growing concerns about subtherapeutic prescribing,” the authors said.
“Evidence from real-world studies shows that a substantial proportion of children and adolescents receive low doses of medication without appropriate upward titration,” they added.
In children and adolescents, the authors said methylphenidate, amphetamines and guanfacine show “increasing median efficacy up to 45mg/day, 25mg/day and 4mg/day, respectively, with no evidence of additional benefit at higher doses”.
While in adults, “amphetamines showed a plateau above approximatively 50mg/day, whereas methylphenidate efficacy increased without evidence of a plateau”, the authors continued.
However, the latter finding could be owing to “sparse data”, they added.
The researchers also found that the risk of discontinuation of medication owing to adverse events increased with dose across all the medications studied.
When amphetamine doses were above 25mg/day for children and 50mg/day for adults, discontinuation risk was greater than placebo, while the same was seen when methylphenidate was raised above 50mg/day for adults, but no clear dose-dependent risk of discontinuation was seen in children, the results showed.
The authors added that their findings suggest that “in general, clinicians should not hesitate to titrate upward from minimum doses when symptom control remains insufficient”.
Lead author Mikail Nourredine, researcher at the Department of Biostatistics at the University of Lyon, France, said: “Overall, our findings suggest that clinicians should avoid using doses that are too low to be effective. If symptoms are not well controlled, the dosage may need to be increased.
“We also found no evidence that going beyond the licensed maximum doses improves average effectiveness, and higher doses are usually linked to more side effects. However, our results derive from group averages.
“Specific individuals with ADHD may benefit from and tolerate well unlicensed doses.”
The authors also published an online tool in March 2026, which they say can be used to show the estimated efficacy and tolerability of each treatment across doses.
Study author Samuele Cortese, National Institute for Health and Care Research research professor at the University of Southampton, commented: “Our study and the tool have the potential to support shared decision-making between clinicians, patients and families when choosing the best dose.
“It is not only a clinician’s decision — patients and caregivers should be involved.”
The authors added that they were unable to stratify their findings by sex, ethnicity or race as most RCTs did not conduct analysis based on these population groups.
The charity ADHD UK has estimated that around 3 million people in the UK live with ADHD.
Henry Shelford, chief executive of the charity ADHD UK, said: “ADHD medication is life-changing for many of us, including me. This report is devastating to read — it’s numerical evidence of the help people aren’t getting.
“Optimal benefit needs the optimal dose, not too low or too high, and calibration takes time. Under-funded NHS services often don’t have the time to work with a patient through different doses, and are nervous of higher doses because the after-care isn’t there to support them. I’ve been caught in this myself.
“I asked for a medication review to recalibrate my dose and was told it would be a two-year wait — and then told the queue was actually closed, and might reopen in two years.
“There is a huge healthcare gap for people with ADHD in this country, and this report is more evidence of it.”
In December 2025, data published by the NHS Business Services Authority showed that prescriptions for ADHD had risen by 5% in the second quarter of 2025/2026, compared with the first quarter. The data also showed that males aged 10–14 years represented the largest number of diagnosed patients.
