This study sought to investigate the use of ADHD medication, including concurrent use with other psychotropic medication, in children/adolescents in five Nordic countries. The results underscored the between-country differences in prevalence and incidence of ADHD medication use, but indicated an overall increase in the prevalence of medication use among children over the study period. In addition, concomitant psychotropic drug use was prevalent among children receiving ADHD pharmacotherapy.
This longitudinal study focused on the pattern of ADHD drug use from 2008 to 2012 among children/adolescents (aged 0–17 years) in Denmark, Finland, Iceland, Norway and Sweden. Information on dispensed medication was obtained from nationwide prescription databases. ADHD medication considered were amfetamine,* dexamfetamine, methylphenidate† and atomoxetine. For those individuals who were prescribed an ADHD drug, additional information regarding their use of psychotropic drugs‡ was collected.
Among Nordic children aged 0–17 years, the prevalence of ADHD medication use increased from 8.9/1000 in 2008 to 14.4/1000 in 2012. Use of medication by pre-schoolers (aged 0–5 years) was rare, and in the 6–17 years age group, the prevalence was 12.8/1000 and 21.4/1000 in 2008 and 2012, respectively. Over the study period, the prevalence of medication use was stable in Norway, but increased steadily in Iceland, Finland and Sweden. In Denmark, prevalence of medication use stabilised after 2010. The rate of ADHD medication use among girls was 69% lower than that of boys.
From 2008–2012, the incidence of ADHD medication use increased from 4.0/1000 to 4.9/1000 and from 1.5/1000 to 2.3/1000 among boys and girls, respectively. After 2010, the number of new users stabilised across all age groups in both sexes. Iceland demonstrated the highest annual incidence relative to other Nordic countries.
The age at drug initiation ranged between 9 years in Finland and 12 years in Sweden, with a median age of 11 years across the Nordic countries. In 2012, the majority of new medication users (94%) received methylphenidate at treatment initiation. The rate of use of the extended-release formulation among new methylphenidate users increased from 66% in 2008 to 83% in 2012.
The prevalence of concomitant ADHD medication use with other psychotropic drugs was higher in girls aged 6–17 years compared with boys in the same age group (33.9% vs 27.0% including melatonin; 20.2% vs 13.8% excluding melatonin). Melatonin was the most preponderant psychotropic agent used, followed by antidepressants and antipsychotics.
This study is limited by its reliance on register-based data, which do not provide information on whether the dispensed drug was actually used by the patient and do not include medication that was administered to children during hospitalisation. In addition, the absence of details on the ADHD diagnosis in the study population prevents the assessment of the adequacy of the treatment. Despite these limitations, the results underscore the increased use of pharmacotherapy since 2008 in children of Nordic countries with ADHD aged 6–17 years, and the frequency of comedication with other psychotropic drugs reflects the extent to which psychiatric comorbidities prevail in this population.
Read more about the use of ADHD medication among Nordic children with ADHD here
*Not marketed in Denmark and therefore excluded from Danish data
†Extended-release and immediate-release formulations
‡Classified into: antipsychotics; anxiolytics; hypnotics and sedatives; antidepressants; and anti-epileptics
Furu K, Karlstad Ø, Zoega H, et al. Utilization of stimulants and atomoxetine for attention-deficit/hyperactivity disorder among 5.4 million children using population-based longitudinal data. Basic Clin Pharmacol Toxicol 2016; Epub ahead of print.