Background <p>Attention-Deficit/Hyperactivity Disorder (ADHD) prevalence rates are around 5–10% of school-aged children. We test whether medication use for ADHD decreases the likelihood of risky behaviour (sexual behaviour, alcohol, tobacco, and drug consumption) and injuries amongst children aged 6–18.</p> Methods <p>We use a large administrative dataset for the whole population of Catalan children in Spain who were born between 1998 and 2012. We apply a scale that contains alternative definitions of ADHD so that over-diagnosis is also identified and estimate a count data model to explain the number of visits whilst accounting for confounding. Our identification strategy relies on instrumenting medication using an average indicator of the probability of prescribing medication for each most visited healthcare centre provider.</p> Results <p>Our results suggest that medication use significantly reduced the number of visits of children diagnosed with ADHD for injuries but not risky behaviour. This finding is robust irrespective of the considered span or the grace period after including ADHD-related comorbidities as controls.</p> Conclusion <p>In line with previous literature, medication use amongst children with ADHD reduces the prevalence of injuries but not risky behaviours.</p>