Increased Prescribing of Attention-Deficit/Hyperactivity Disorder Medication and Real-World Outcomes Over Time

Abstract

Importance: The prescription of attention-deficit/hyperactivity disorder (ADHD) medications has risen substantially in many countries over the last 20 years. However, whether the real-world benefits of ADHD medications change with increased prescription rates within a society remains unknown. Objective: To examine whether the associations between ADHD medications and real-world outcomes (self-harm, unintentional injury, traffic crashes, and crime) change as prescription rates rise. Design, Setting, and Participants: This study used a self-controlled case series design. It was a population-based study using Swedish National Registers that included individuals who used ADHD medications in Sweden between 2006 and 2020. Data were analyzed from October 2023 to November 2024. Exposure: ADHD medication use. Main Outcomes and Measures: Rates of self-harm, unintentional injury, traffic crashes, and crime during medicated vs nonmedicated periods. The associations between ADHD medication and these real-world outcomes were examined across 3 time periods, 2006 to 2010, 2011 to 2015, and 2016 to 2020, during which ADHD medication prevalence increased from 0.6% to 2.8%. Results: There were 247420 individuals identified (99361 females [40.2%] and 148059 males [59.8%]) aged 4 to 64 years in Sweden who used ADHD medications between 2006 and 2020. ADHD medication was consistently associated with lower risks for self-harm (incidence rate ratio [IRR] ranged from 0.77; 95% CI, 0.73-0.81 to 0.85; 95% CI, 0.82-0.88), unintentional injury (IRR ranged from 0.87; 95% CI, 0.84-0.89 to 0.93, 95% CI, 0.91-0.95), traffic crashes (IRR ranged from 0.71; 95% CI, 0.67-0.77 to 0.87; 95% CI, 0.83-0.91), and crime (IRR ranged from 0.73; 95% CI, 0.71-0.75 to 0.84; 95% CI, 0.82-0.85) across different age groups, sexes, and over time. However, the associations between ADHD medication use and lower risks of unintentional injury (P value for trend