August 13, 2025

expert reaction to target trial emulation study of ADHD medication and risk of adverse outcomes

A target trial emulation study published in The BMJ looks at ADHD drug treatment and the risk of adverse outcomes. 

Prof Ian Maidment, Professor in Clinical Pharmacy, Aston University, said:

“This study builds on existing research that found that treatments for ADHD reduce the risk of criminality, suicidality behaviour amongst others. There are a number of limitations in using observational data, as in this study. The databases have detailed information on dispensing, but we don’t know whether or not the patient took the medication. The study also couldn’t assess the impact of different doses and ethnicity is not reported. However, overall the study adds to our understanding of the potential benefits of these drugs.”

From our colleagues in Australia:

Professor Adam Guastella is a Michael Crouch Chair in Child and Youth Mental Health in the Clinic for Autism and Neurodevelopment research from the Brain and Mind Centre and is from the Children’s Hospital Westmead Clinical School at The University of Sydney

“It’s important to understand the risks and benefits of ADHD medication use, to give people informed choices about what they use to support themselves or their children. People can spend a long time seeking a diagnosis and discussing treatment, and the investment of time needs to be worth it and evidence based. So it’s important to understand the breadth of possible impact.
Its always helpful to know if medications can impact daily life beyond reducing reducing symptoms. This information is also important for government, to help policy makers understand the potential benefits of treatment for broader society, such as mental health or criminal outcomes.

This study shows that individuals who started ADHD medication showed a reduction in suicidality, substance misuse and criminality. Such benefits have been shown repeatedly in previous studies, but the large sample size, use of a national registry, and more sophisticated analysis give greater confidence in these results that findings aren’t explained by something else other than medication use. This is one of a number of studies that show the benefits of stimulant medication for people with ADHD and their life. People should know that if ADHD medications work for them and their child, that there will likely be many other positive impacts on life from treatment. Such effects will not work for everyone and there is still a need to understand why many individuals benefit from ADHD medication and some do not. Finally, even though the study was rigorous in its design, one cannot rule out that other unaccounted factors could be associated with these effects and the study focused on adults.”

Adam has not declared any conflicts of interest.

Professor Rob Hester is from the Melbourne School of Psychological Sciences at the University of Melbourne

“ADHD, with its core symptom of impulsivity, increases our risk for substance misuse and dependence. Due to the short-term follow-up of clinical trials, it has been unclear whether stimulant medications for ADHD reduce this risk, or inadvertently increase it (particularly for medication misuse). The Zhang et al. study followed up nearly 150,000 Swedish people (children and adults) diagnosed with ADHD since 2007, finding that medication significantly reduced the incidence of substance misuse, with the effect increasing when comparing stimulant to non-stimulant ADHD medication prescription. The current study addresses many of the limitations of past research on ADHD-related substance use risk, with their extended follow-up and comprehensive population-based inclusion, though is limited by the typical confound that upwards of 60% of people do not seek treatment for substance misuse.”

Rob has declared he has no conflicts of interest.

Dr Stephen Bright is a Senior Lecturer (Addiction) at Edith Cowan University

“This research provides further evidence that stimulant medication treatments for ADHD can be life changing, reducing the risk of individuals experiencing a motor vehicle accident and drug-related harms, in addition to reducing the likelihood that they will engage in criminal behaviour and suicide. Yet it is very difficult for many Australians to access a paediatrician or psychiatrist who is able to commence stimulant medication treatments where appropriate due to extensive waitlists, in addition to financial and regulatory obstacles. As such, a number of people with undiagnosed ADHD continue to present for help with their drug use at alcohol and other drug treatment services, while others remain in prison.

While there are concerns about the over-prescribing of stimulant medications in Australia and the potential diversion of stimulant medications for non-medical use, it is important that we find the right balance between protecting the community from diverted medications and the right of people with ADHD to access a gold standard treatment so that they are able to thrive and be productive members of society.”

Stephen has declared that he has no conflicts of interest.

Professor Stuart Kinner is Head of the Justice Health Group at Curtin University and Murdoch Children’s Research Institute

“This is a landmark piece of research, convincingly demonstrating the diffuse benefits of ADHD diagnosis and treatment. Timely drug treatment led to significant reductions in suicidal behaviour, substance use, transport accidents, and criminality. These findings confirm what many already know: failure to diagnose and treat ADHD can lead to self-medication with alcohol or other drugs, poor mental health, injury, and incarceration. Too many people with undiagnosed ADHD end up in the criminal justice system, where their condition may remain undiagnosed and untreated. It is estimated that around one in four people in prisons and youth detention centres have ADHD, although this is frequently undiagnosed.

There are two key messages: (1) Greater investment in ADHD screening for children and adolescents in schools could reduce the number of young people – particularly vulnerable and marginalised young people – who end up self-medicating their ADHD with substances, and living lives distinguished by poor mental health, injury and – far too often – criminalisation of neurodivergence. (2) For people who end up in the criminal justice system, screening for ADHD could lead to better health outcomes for those diagnosed and treated, and reduce rates of reoffending. That’s a win for public health, and a win for public safety.”

Stuart has declared that he has no conflicts of interest.

‘ADHD drug treatment and risk of suicidal behaviours, substance misuse, accidental injuries, transport accidents, and criminality: emulation of target trials’ by Le Zhang et al. was published in The BMJ at 23:30 UK time on Wednesday 13th August. 

DOI: https://dx.doi.org/10.1136/bmj-2024-083658

Declared interests
Prof Ian Maidment: No DOI

This Roundup was accompanied by an SMC Briefing.