Is ADHD on the rise? No – but that answer doesn’t tell the whole story

Is ADHD in children on the rise? An assessment of thousands of studies released since 2020 suggests, surprisingly, that the answer is no – but the researchers behind the work have expressed their frustration at the poor quality of data available, meaning that the true picture remains murky.

“The best data we have suggests that there has been no meaningful increase in ADHD prevalence,” says Alex Martin at King’s College London, but that masks a larger problem, she says. “Most of the research is too biased to draw conclusions from.”

While there may have been no rise since 2020, the data shows there are still big differences between countries in terms of the proportion of children being diagnosed with ADHD.

The team’s initial search for recent studies on the prevalence of ADHD produced more than 9000 results. “We read every single one,” says Martin. But only 40 studies included original data from after 2020 that was based on formal diagnoses or surveys that could be included in the analysis. And of these, only four were high-quality studies that avoided serious biases – for instance, through diagnoses being made by qualified clinicians.

Two of the four were from the US, one was from Canada and one was from Sweden. Each looked at diagnoses over a number of years. For example, one of the US studies looked at data from 2017 to 2022. According to these studies, in the US, around 10 per cent of children have been diagnosed with ADHD, compared with 8 per cent in Canada and 3 per cent in Sweden.

The finding of no increase is surprising because there has been much more awareness of ADHD in recent years and reports of many more people seeking diagnoses and help with the condition. “It seems that our best evidence suggests that the true rate of ADHD probably isn’t increasing that much,” says Philip Shaw, also at King’s College London but not part of Martin’s team.

But Shaw says in the UK the number of diagnoses in both children and adults definitely increased between 2000 and 2018, and he thinks it’s likely it has continued to rise. “For sure, the number seeking assessment for ADHD is rising.”

Shaw thinks this is because health services are “playing catch-up”. For instance, in 2018, it was estimated that 5 per cent of all people in the UK had ADHD, but the highest proportion of formal diagnoses in any group was just 3.5 per cent in boys aged between 10 and 16.

“There’s both an increased recognition and – very welcome – less stigma around ADHD, which means that people are increasingly coming forward for assessment,” he says. “And while we’re working through that backlog, there are simply going to be long waiting lists.”

“The history of ADHD, in the UK at least, is one of chronic under-recognition, especially for certain demographic groups, in particular for girls and women,” says Edmund Sonuga-Barke, also at King’s College London but not part of Martin’s team. “So, part of the increase in diagnosis we’ve seen over the last 10 or so years is really a resetting or recalibration or a catch-up.”

“It’s hard to draw conclusions about increased attention surrounding ADHD,” says Martin. “So, as well as there being very unreliable recent data, some of the data that is being published recently is actually very much out of date and we have to be really cautious when we are reporting prevalence estimates and checking where that data is coming from.”