Prescribing medication to people newly diagnosed with attention deficit hyperactivity disorder (ADHD) is associated with significantly reduced risks of suicidal behaviours, substance misuse, transport accidents and criminality, a new study has found.
ADHD is a developmental impairment of the brain’s executive functions, affecting around 5 per cent of the population in Ireland. Many people diagnosed with ADHD have trouble with impulse-control, focusing and organisation, according to ADHD Ireland.
In a study published in the British Medical Journal (BMJ), researchers in Sweden drew on data from its national registers from 2007 to 2020 to examine the effects of ADHD drug treatment in 148,581 individuals aged between 6 and 64 years, with a new diagnosis of the disorder.
Using a technique called target trial emulation, they assessed first and recurrent events for five outcomes over two years after diagnosis. The average age of those in the study were 17 years old, and 41 per cent were female.
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Of the 148,581 individuals with ADHD, 84,282 (57 per cent) started drug treatment for the disorder.
After accounting for factors including age, sex, education level, psychiatric diagnoses and medical history, ADHD medication was associated with reduced rates of a first occurrence of four of the five outcomes, the study found.
According to the researchers, there was a 17 per cent reduction for suicidal behaviour, 15 per cent for substance misuse, 12 per cent for transport accidents and 13 per cent for criminality.
The reduction was not statistically significant for a first-time accidental injury, but there was a reduction for people with recurrent events where accidental injuries reduced by 4 per cent.
The authors suggested a number of possible explanations for the reduction. These include reduced impulsivity, which might lower criminality by curbing aggressive behaviour, and enhanced attention, which might decrease the risk of transport accidents by minimising distractions.
The researchers acknowledge a number of limitations to the study, including not being able to assess data on non-drug treatment methods or the impact of other factors, such as severity, lifestyle or genetic predispositions.
Ken Kilbride, chief executive of ADHD Ireland, said not everybody with ADHD is going to need medication but for those who do, it is important to ensure there are no barriers in place.
“The challenge at the minute can be to get diagnosis and get that medication. There is a big logjam in this area,” he said.
“We have known there is a socio-economic cost to ADHD. It costs €2 billion in Ireland every year due to lower life expectancy, higher rates in prison, unemployment etc. There is always a stigma around medication, particularly among children. So it is great to have this research to prove just how beneficial it can be for some people.”
In recent years, there has been a significant increase in the number of people seeking diagnosis and treatment for ADHD in Ireland – particularly among women.
In February, The Irish Times published data which found the number of prescriptions for ADHD medications increased by 87 per cent over the past five years.
The rise among women and girls was much more acute, with prescriptions increasing by almost 180 per cent between 2020 and 2024, from 19,827 to 55,452 last year.
The surge among women is being partly attributed to increasing awareness and prevalence of the condition on social media platforms, particularly TikTok. Women have also typically been underdiagnosed.
Those working in the sector have raised concerns about online content on the topic, after a number of academic studies showed many of these posts contained inaccurate or misleading information.
