Nationwide trends in the use of ADHD medications in the period 2006-2022: a study from the Norwegian prescription database.

Background: The use of medication for Attention-Deficit/Hyperactivity Disorder (ADHD) increased globally throughout the early 2000s. This study examine trends in prevalences and incidences of medication use in Norway from 2006 to 2022.

Methods: Data from the Norwegian Prescription Database were used to present one-year-prevalence and incidence rates of ADHD medication (ATC-group N06BA and C02AC02) for the overall population (ages 6-64) and within sex and age subgroups of children (ages 6-17) and adults (ages 18-64). Incident use was defined as the dispensing of medication, with no recorded use in the previous two calendar years.

Results: The overall prevalence of ADHD medication use in 6- to 64-year-olds increased from 5.2 to 19.4 per 1000 in the period, most pronounced from 2020 and onwards. While males experienced a nearly threefold increase in use (from 7.3 to 20.6 per 1000), the use among females increased almost sixfold during the study period (from 3.0 to 18.1 per 1000). Consequently, the male-to-female prevalence-ratio decreased from 2.4 to 1. Children exhibited a higher prevalence of use compared to adults throughout the period, although the largest relative increase was observed in adults, particularly in female adults. In children the male-to-female ratio decreased from 3.2 to 2.0, primarily due to an increasing use in 13-17-year-old females. Among adults, prevalences were similar across most age groups, with the highest rates observed among those aged 18-24, where female use exceeded male use by the end of the period. The male-to-female prevalence-ratio in adults decreased from 1.6 to 0.9 during the period. Parallel to prevalent use, overall incident use increased from 1.4 to 5.0 per 1000 during the period, with the most pronounced increase occurring from 2020 and onwards. From this point, incident use among females aged 13-17, 18-24, and 25-34, exceeded that of males. The male-to-female incidence-ratio decreased from 1.8 to 0.9. The overall incidence to prevalence ratio remained similar throughout the period, being 0.27 in 2006 and 0.25 in 2022.

Conclusion: A sustained increase in the prevalence of ADHD medication use was observed, with the most pronounced rise occurring among females and adults from 2020 and onwards. By 2022, the overall gender disparity in ADHD medication use had diminished, which should be considered in the context of a steep increase in incident use among adolescent and young adult females starting from 2020.