Study Identifies Optimal Dosages for Five ADHD Medications

ADHD Medication Study Reveals Key Insights on Dosing and Effectiveness

A major new study published in The Lancet Psychiatry on May 14, 2026, has shed light on how dosage affects the effectiveness and side effects of five common ADHD medications.

> "Doses that are too low may be ineffective; increasing dosage may improve symptom control if needed."

Led by Professor Samuele Cortese from the University of Southampton, the research team analyzed data from 113 clinical trials involving over 25,000 participants. Using a sophisticated dose–effects network meta-analysis, the study provides the most comprehensive look yet at how medication dosage impacts outcomes across different age groups.

A free online tool based on these findings has been developed to help clinicians and patients make more informed decisions.

Key Findings

The study revealed several crucial insights for both doctors and patients:

• Effectiveness and side effect patterns vary significantly between different medications and across age groups (children vs. adults).
• Starting too low is a common pitfall. The research found no benefit to using doses that are too low, as they may simply be ineffective.
• If symptoms remain uncontrolled, increasing the dosage is a logical and evidence-backed next step.
• No evidence supports exceeding licensed maximum doses to improve average effectiveness across a population.
• Higher doses are generally linked to more side effects. The balance between symptom control and tolerability is key.
• Individual responses matter. The results are based on group averages, meaning real-world outcomes can vary from person to person.

Expert Commentary

Dr. Mikail Nourredine, first author from the University of Lyon, offered clear advice for clinicians:

"Clinicians should avoid excessively low doses. If symptoms are uncontrolled, dosage may need to be increased. However, while we found no evidence supporting the use of unlicensed doses for average effectiveness, some individuals may still benefit from them."

Professor Samuele Cortese, NIHR Research Professor at the University of Southampton, emphasized the importance of collaboration:

"This tool can support shared decision-making. Patients and caregivers should be actively involved in dose selection to find the right balance for each individual."

Why This Matters

ADHD affects approximately 5% of school-age children and 2-3% of adults worldwide. While prescriptions for ADHD medications have risen, clinical guidelines have historically offered limited, evidence-based guidance on dosing strategies.

The goal is to move away from guesswork and toward personalized, data-informed treatment.

This research, funded by the National Institute for Health and Care Research (NIHR) , aims to fill that gap by giving clinicians a clear framework for starting and adjusting medication doses.