Injuries represent the largest disease burden and most common cause of death in children. Attention deficit hyperactivity disorder (ADHD) is associated with increased mortality, with accidents being the most common cause of death in ADHD. However, it is not known whether pharmacological treatment has any modifying effect on the risk of injuries in children and adolescents with ADHD.
Using Danish national registers, we followed a cohort of 710 120 individuals, including 4557 individuals diagnosed with ADHD before age 10 years. Using a quasi-experimental, difference-in-difference design, we estimated the odds ratios (ORs) for injuries and the mean change in prevalence rates of injuries and emergency ward visits before and after treatment, with matched untreated children with ADHD at the same age serving as controls.
Children with ADHD were more likely to sustain injuries, compared with children without ADHD, at age 10 years (adjusted OR=1·29, 95% CI 1·22–1·37) and at age 12 years (adjusted OR=1·30, 1·23–1·37). From age 5 to 10 years, the prevalence of injuries in children with ADHD who were treated with ADHD drugs decreased from 19% to 14%, compared with a prevalence of about 17% in non-treated children with ADHD. This corresponded to an adjusted difference-in-difference reduction in prevalence of injuries at age 10 years of 31·5% (8·2–54·8) and 43·5% (18·1–69·0) at age 12 years due to treatment. Pharmacological treatment also reduced the prevalence of emergency ward visits at age 10 years (28·2%, 6·3–50·1) and age 12 years (45·7%, 25·8–65·7).
Among all children in Europe and the USA,1,2 injuries represent the largest disease burden, and this study is the first to show that children with ADHD are no exception. In fact, ADHD almost doubles the risk of injuries. Impulsivity, executive dysfunctions, hyperactive behaviour, and perhaps also a higher tendency to engage in risk-taking behaviour might mediate this increased risk of injuries in children with ADHD. However, pharmacological treatment with stimulant drugs seems to normalise the risk in this vulnerable group of children and adolescents, by reducing injuries by up to 43%. In light of this and our previous findings of accidents being the most common cause of death in individuals with ADHD, these results are of major public health importance.