Trends in psychostimulant drug use among adults in the Netherlands

Abstract

Background Use of psychostimulants among children and adolescents receives a lot of attention. However, less is known about the use of these drugs among adults. The aim of our study was to describe trends in the use of psychostimulants among adults over time. Methods Data on adults (≥ 18 years), receiving two or more prescriptions for a psychostimulant drug (ATC-code N06BA; excluding modafanil) within 12 months, were selected from the IADB, a Dutch database of filled prescriptions (59 public pharmacies, about 600.000 patients). We calculated both the number of new users as well as the total number of users of psychostimulants in 2004-2014. Furthermore, we determined the most commonly prescribed psychostimulant drug and whether the psychostimulant was initiated by GP or medical specialist. Results The proportion of psychostimulants users (methylphenidate, dexamphetamine and amphetamine) increased from 1,5 per 1000 adults in 2004 to 7,8 per 1000 adults in 2014. Users were mainly male (63,0%) and methylphenidate predominated (85,7%). The proportion of new users of these drugs increased from 0,5 to 1,5 per 1000 adults. The largest increase was observed among young adults (< 30 year). Since 2012, the increase in new users seems to stabilize. Around 40% of new treatments were initiated by GPs. Conclusion The large increase in use of psychostimulants seems mainly due to an increase in the proportion of new users, especially among young adults. As psychostimulants are only approved for the treatment of ADHD among children (>6 years) and adolescents, short and long term effects and side effects of these drugs need to be assessed in the adult population