Key Summary
- Researchers have identified the most effective dose ranges for several ADHD medications by analysing data from over 25,000 people across 113 clinical trials.
- The study, published in The Lancet Psychiatry, shows that optimal doses differ by medication and age group, and warns against both too‑low and above‑maximum doses in routine use.
- A free online tool based on the findings is available to help clinicians, patients, and families choose and understand the best dose for individual ADHD treatment.
Researchers have identified the most effective dose ranges for several ADHD medications by analysing data from more than 25,000 participants across 113 clinical trials.
For example, in children and adolescents, methylphenidate, amphetamines, and guanfacine showed increasing median efficacy up to 45 mg/day, 25 mg/day and 4 mg/day, respectively. In adults, amphetamines showed a plateau above approximatively 50 mg/day.
The study, led by Professor Samuele Cortese of the University of Southampton and published in The Lancet Psychiatry, was funded by the National Institute for Health and Care Research (NIHR).
The team has also developed a free online tool based on the findings to support clinicians, patients, and families when deciding on the right dose.
ADHD is one of the most common neurodevelopmental disorders, affecting about 5 per cent of school‑age children and 2–3 per cent of adults.
Medication is a core part of treatment, and prescriptions have risen sharply in recent years. However, most clinical guidelines give limited advice on the best dose.
Finding the right level is important: doses that are too low may be ineffective, while doses that are too high increase side effects.
The research team used an advanced technique called dose–effect network meta‑analysis to compare the balance of effectiveness and side effects across different doses of each medication.
The results show that the optimal “sweet spot” varies by drug type and by age group, highlighting that a one‑size‑fits‑all approach is not suitable.
Dr Mikail Nourredine from the University of Lyon, the study’s first author, said clinicians should avoid very low doses that are unlikely to control symptoms and consider increasing the dose if treatment is not working well.
He noted there is no evidence that going beyond the licensed maximum dose improves overall effectiveness, and higher doses are usually linked to more side effects, even though some individual patients may tolerate unlicensed doses well.
Professor Cortese added that the study and the online tool can support shared decision‑making, where clinicians, patients, and families discuss the likely benefits and risks of each dose.
The tool helps explain why a particular dose has been chosen and may encourage better adherence, while the team continues to work on more personalised dosage recommendations based on individual patient factors.
