Diagnoses for attention deficit hyperactivity disorder (ADHD) have increased in many countries across all age groups, our latest review has found . We have also shown that prescriptions for ADHD treatments have seen similar increases across all age groups.
Authors
- Barbara Jacquelyn Sahakian
Professor of Clinical Neuropsychology, University of Cambridge
- Christelle Langley
Postdoctoral Research Associate, Cognitive Neuroscience, University of Cambridge
Our latest review, published in the Journal of Psychopharmacology , drew together the recently published research on ADHD diagnoses and prescriptions across the world.
We found that in the UK, increases in recorded ADHD diagnoses and treatment prescriptions occurred across all age groups between 2000 and 2018.
The greatest rise in ADHD diagnoses across this period was among children. However, there was also a distinct increase in adults. For example, among men aged 18-29 there was an approximately 20-fold increase in diagnoses and an almost 50-fold increase in prescriptions.
The sex ratio of ADHD diagnoses in childhood and adolescence was approximately 4:1 male to female. However, the ratio of diagnoses in adulthood is nearly 1:1. This shift may partly reflect increased recognition of how ADHD presents in girls and adults - groups that have historically been underdiagnosed.
Alongside these increases in ADHD diagnoses, there has also been an increase in prescriptions for ADHD treatments.
In England, prescriptions of central nervous system stimulants (the main prescription treatments for ADHD) increased by 32% in adults over 18 in 2021-22. In children under 17, prescriptions increased by 12% from 2022-23. This was also the first time that more adults were prescribed these drugs than children since records started in 2015.
A retrospective study of over 154 million people from 13 countries, including in North America, Europe and Asia, demonstrated that use of ADHD medication prescriptions had increased in these regions as well.
Why diagnoses and prescriptions are increasing
A few key factors can largely explain the increase in both ADHD diagnoses and prescriptions that we've seen. This includes increased public awareness of the condition, better understanding by doctors of the way symptoms present and the availability of new and improved medications.
Additionally, there is better awareness of how ADHD manifests in groups who may have previously been missed because their symptoms did not match with those typically exhibited in boys and adolescents. This includes women and girls and people with predominantly inattentive symptoms .
However, these factors may only tell part of the story. Our review also revealed other drivers may deserve careful consideration.
For instance, there has been much debate over whether there is an issue of overdiagnosis and over-prescribing . Legitimate questions about whether some attention difficulties might be over-medicalised have also been raised . On the other hand, some authors have argued that there is no evidence to suggest overdiagnosis is occurring in the UK.
Understanding the full picture requires looking beyond the obvious explanations to examine cultural, economic, social and technological pressures in a globally competitive environment that may be influencing both diagnosis rates and treatment choices .
Looking forward
The rising rates of ADHD diagnoses and treatment represent a complex picture. There have been genuine improvements in recognising a real disorder that was historically overlooked (particularly in adult men and women), better clinical awareness and perhaps also some degree of over-identification in certain environments.
What seems clear is that ADHD, long thought of as a children's disorder, is now being treated as what it truly is: a lifelong neurodevelopmental disorder affecting millions of people across the globe.
As awareness continues to grow, the challenge ahead lies in preserving limited NHS resources, while ensuring those who genuinely need these resources have improved access.
The wait time for an ADHD diagnosis in England currently ranges from two to 15 years . With increasing rates of diagnoses and prescriptions to manage ADHD, there are concerns that demand will soon outstrip NHS capacity entirely .
What could be a solution is the discovery of ADHD biomarkers - an objectively measurable indicator of a biological state or condition that can be detected in signatures in the brain. Currently, ADHD is diagnosed by a doctor who often has to rely on self-reported symptoms. Having biomarkers could improve the accuracy of diagnoses, ensuring those who have the condition get the support they need earlier on.
Barbara Jacquelyn Sahakian receives funding from the Wellcome Trust. Her research work is conducted within the NIHR Cambridge Biomedical Research Centre (BRC) Mental Health and Neurodegeneration Themes. She receives Royalties from Cambridge University Press for Brain Boost: Healthy Habits for a Happier Life.
Christelle Langley is funded by the Wellcome Trust. Her research work is conducted within the NIHR Cambridge Biomedical Research Centre (BRC) Mental Health and Neurodegeneration Themes. She receives Royalties from Cambridge University Press for Brain Boost: Healthy Habits for a Happier Life.
