Almost 2.5 million people in England are likely to have attention deficit hyperactivity disorder (ADHD), figures suggest.
ADHD is a neuro-developmental disorder and people with the condition may have trouble concentrating or sitting still.
Other symptoms include being easily distracted, forgetfulness, finding it hard to follow instructions or organise time, and making impulsive decisions.
It is the first time an estimate has been made publicly available of how common the condition may be among the population.
According to NHS England, a total of 2,498,000 people may have ADHD, including those without a diagnosis.
Of this number, an estimated 741,000 are children and young people aged five to 24.
The figures were developed using estimates from the National Institute for Health and Care Excellence (Nice), which suggests that around 3-4 per cent of adults and 5 per cent of children and young people have ADHD.
While ADHD is not usually diagnosed in children under five as some traits can be part of typical development.
While the prevalence in youngsters aged four and under have been calculated to give an insight into how many may go on to be diagnosed in the future.
According to the NHS estimates, some 147,000 under-fives are likely to have ADHD.
The figures also suggest that more than half a million people (549,000) in England were waiting for an ADHD assessment at the end of March 2025.
This is up from 416,000 a year earlier at the end of March 2024.
Of the 549,000 likely to be waiting for ADHD assessment in March this year, some 304,000 had been waiting at least a year while 144,000 had been waiting at least two years.
More than two-thirds (382,000) were aged between five and 24.
Louise Ansari, chief executive at Healthwatch England, said the figures are “a first step in understanding the scale of demand for ADHD care”.
“Our new research highlights that many people with ADHD may simply be going without support,” she added.
“Long waits for assessments are one of the reasons people who show ADHD traits don’t seek help, while those waiting for an assessment struggle to navigate the long waits.
“While we welcome today’s publication, however, there is a way to go to ensure data is comprehensive and robust.
“A move to official waiting list data in the longer term would give a clearer picture of waiting times, including who is experiencing the longest waits and why,”she said.