Self-harm risk peaks before ADHD medication initiation, study finds

Self-harm risk among patients with ADHD peaks in the 90 days before ADHD medication initiation rather than after treatment begins, according to the study authors.¹ Their multinational self-controlled case series, published in BMJ Mental Health, drew on health records from 5 health care systems.¹ Risk stayed elevated after initiation but declined, a pattern the investigators say does not support medication as the main driver of self-harm.²

Concerns about self-harm can influence whether patients start or continue ADHD treatment, and earlier studies of ADHD medication and self-harm produced conflicting evidence.² The investigators designed this analysis to address those concerns using a common scientific approach across countries.²

The research team was led by Adrienne Chan, a pharmacy lecturer, and Regius Professor Ian Wong of Aston Pharmacy School at Aston University.² Collaborators included groups from UCL, the University of Hong Kong, the University of Auckland, Sungkyunkwan University, and National Cheng Kung University, among other institutions.² Investigators analyzed population-based databases from Hong Kong, New Zealand, South Korea, Taiwan, and the UK covering more than 460,000 people.^1,2

The analysis included individuals who initiated ADHD medication and had a record of self-harm between 2001 and 2020.¹ Using a common data modelling approach and conditional Poisson regression, investigators calculated incidence rate ratios (IRRs) for self-harm.¹ Three risk periods were compared with nonexposure periods: the 90 days before initiation, the first 90 days of medication use, and the subsequent treatment period.¹

Risk was highest during the 90 days before medication initiation (pooled adjusted IRR, 2.58; 95% CI, 2.12-3.13).¹ Risk was lower in the first 90 days of medication use (pooled adjusted IRR, 1.78; 95% CI, 1.23-2.57).¹ The lowest risk occurred during the subsequent treatment period (pooled adjusted IRR, 1.27; 95% CI, 1.01-1.60).¹

Consistent self-harm findings across 5 health care systems point to a pretreatment monitoring window

The pretreatment peak appeared in all 5 health care systems, with lower, although still elevated, risk after treatment began.² The authors describe these consistent findings as evidence against ADHD medications as the main driver of self-harm.²

The investigators emphasize close monitoring of patients with ADHD, particularly those whose symptoms worsen before they start treatment.² Recognizing this window, they note, allows clinicians to provide support before self-harm occurs.²

The collaboration also established an international research platform for additional medication safety questions.² Planned work will examine a wider range of health outcomes, including what happens when patients stop or restart treatment.² Investigators will also study whether ethnicity and socioeconomic disadvantage contribute to inequalities in ADHD care across health care systems.²

Patient-level data remained securely within each participating country throughout the analysis, according to the investigators.² The approach allowed the team to pool findings from 5 systems while maintaining local data governance standards.²

According to Chan, the findings suggest many patients are already at their highest risk before treatment begins.

“This highlights an important opportunity for earlier intervention,” Chan said in a statement.²

For pediatricians, the findings position the 90 days before ADHD treatment initiation as a period of heightened self-harm risk warranting close attention.¹,² The data may also inform conversations with patients and caregivers concerned about medication safety, since risk declined after initiation.¹ Because risk remained above nonexposure levels during treatment, ongoing monitoring after the first prescription remains important.¹

References

1. Chan AYL, et al. ADHD medication use and risk of self-harm: a multinational self-controlled case series study. BMJ Ment Health. 2026;29(1):e302819. doi:10.1136/bmjment-2026-302819

2. Aston University-led international study finds ADHD medication unlikely to raise risk of self-harm. News release. Aston University. October 2026. Accessed October 28, 2026. https://mentalhealth.bmj.com/content/29/1/e302819