People with ADHD who take medication have a lower risk of suicidal behaviours, substance abuse, transport accidents and criminality than those who don't, according to a new study jointly led by the University of Southampton and the Karolinska Institute in Sweden.
A new study published in The BMJ has found that for two years of pharmacological treatment, people who took medication for ADHD were less likely to experience these harmful incidents than those who didn't take medication.
"These benefits might be explained by reductions in impulsivity and improvements in attention and executive functions," says Samuele Cortese , a National Institute for Health and Care Research (NIHR) Research Professor at the University of Southampton and co-senior author on the paper.
"For instance, reduced impulsivity might lower criminality by curbing aggressive behaviour, while increased attention might decrease the risk of transport accidents by minimising distractions."
The likelihood was most reduced amongst people exhibiting a recurring pattern of behaviour, such as multiple suicide attempts, numerous drug relapses or repeat offending. Medication didn't reduce the risk of a first-time accidental injury, but did reduce the risk of recurring ones.
The study is the first of its kind to show the beneficial effect of ADHD medication on these broader clinical outcomes using a novel statistical method and data representative of all patients in routine clinical care from a whole country.
Attention-deficit/hyperactivity disorder (ADHD) affects around five per cent of children and 2.5 per cent of adults globally. It is linked to increased risks of suicidal behaviours, substance abuse, accidental injuries, transport accidents and criminality.
An international team of researchers wanted to establish if medication reduces these risks. They examined multiple population and health records in Sweden linked by unique personal identification numbers, assigned to every resident in Sweden.
The team used a novel study design called a 'trial emulation' to simulate a trial using existing real-world data from 148,581 people with ADHD.
Comparing those who had started medication within three months of diagnosis with those who hadn't, they examined the records over the following two years.
They found medication reduced the first occurrence of four of the five incidents (with accidental injury being the exception) and all five outcomes when considering recurring incidents.
Those taking stimulant medication were associated with the lowest incident rates, compared to non-stimulant medications.
"This finding is consistent with most guidelines that generally recommend stimulants as the first-line treatment, followed by non-stimulants," explains Dr Zheng Chang, senior author of the study from the Karolinska Institute.
"There is an ongoing discussion regarding whether methylphenidate (a stimulant medication for ADHD) should be included in the World Health Organization model list of essential medications, and we hope this research will help to inform this debate."
Professor Cortese added: "The failure form clinical services to provide timely treatments that reduce these important outcomes represents a major ethical issue that needs to be addressed with urgency, with the crucial input of people with lived experience. In England, the NHS ADHD task force is working hard to tackle this issue."
The paper ADHD drug treatment and risk of suicidal behaviours, substance misuse, accidental injuries, transport accidents, and criminality: emulation of target trials is published in The BMJ and is available online .
The research was supported by the Swedish Research Council and the NIHR.
