A recent study reported on the use of ADHD medication among adults with ADHD in Denmark, Finland, Iceland, Norway and Sweden. The results showed that medication use rose more than 2-fold over a period of 5 years, and that adults constitute a substantial proportion of persons treated with ADHD medication in Nordic countries.
This population-based study examined the use of ADHD medication* in the entire Nordic adult population (n=15.8 million; aged 18–64 years) during 2008–2012. Based on information from nation-wide prescription registers in each country, there was a total of 76,896 adult ADHD medication users across the five countries.
During the study period, the prevalence of drug use increased from 2.4/1000 to 5.3/1000 in men and from 1.8/1000 to 4.4/1000 in women. This increase was noted in all countries except Finland. Methylphenidate was the most frequently prescribed drug, accounting for 87–88% of drug use, and was the preferred drug for treatment initiation (88% of new users received methylphenidate on the first prescription).
A modest increase was observed in the overall annual incidence of medication use throughout 2008–2012. Country-specific variations over time were observed, with incidence of medication use rising the most in Iceland and to a lesser extent in Denmark and Sweden, while remaining stable in Finland and Norway.
Within the first year of treatment, 13% of new drug users filled the initial prescription only, 9% filled one additional prescription and 79% filled more than three prescriptions of any ADHD medication. The rate of psychotropic drug use among users of ADHD medication ranged between 38–77%, and psychotropic co-medications were more prevalent in older ADHD patients, and in women with ADHD relative to men with the syndrome.
This study is limited by the reliance on prescription registers that do not provide information on medications administered in hospitals and institutions. In addition, there was a lack of information on the underlying ADHD diagnosis to allow for an evaluation of the validity of treatment. These data emphasise the substantial increase in ADHD medication use, and highlight the need for more studies aimed at the assessment of long-term efficacy and safety of these medications in the adult population.
*Methylphenidate (extended release and immediate release), atomoxetine, amphetamine and dexamphetamine
Karlstad Ø, Zoëga H, Furu K, et al. Use of drugs for ADHD among adults-a multinational study among 15.8 million adults in the Nordic countries. Eur J Clin Pharmacol 2016; 72: 1507-1514.